Cytokine/anti-cytokine therapy - novel treatments for asthma?

Endoplasmic reticulum stress enhances the expression of TLR3-induced TSLP by airway epithelium

Thymic stromal lymphopoietin (TSLP) is an epithelial-derived pleiotropic cytokine that regulates T-helper 2 (Th2) immune responses in the lung and plays a major role in severe uncontrolled asthma. Emerging evidence suggests a role for endoplasmic reticulum (ER) stress in the pathogenesis of asthma. In this study, we determined if ER stress and the unfolded protein response (UPR) signaling are involved in TSLP induction in the airway epithelium. For this, we treated human bronchial epithelial basal cells and differentiated primary bronchial epithelial cells with ER stress inducers and the TSLP mRNA and protein expression was determined. A series of siRNA gene knockdown experiments were conducted to determine the ER stress-induced TSLP signaling pathways. cDNA collected from asthmatic bronchial biopsies was used to determine the gene correlation between ER stress and TSLP. Our results show that ER stress signaling induces TSLP mRNA expression via the PERK-C/EBP homologous protein (CHOP) signaling pathway. AP-1 transcription factor is important in regulating this ER stress-induced TSLP mRNA induction, though ER stress alone cannot induce TSLP protein production. However, ER stress significantly enhances TLR3-induced TSLP protein secretion in the airway epithelium. TSLP and ER stress (PERK) mRNA expression positively correlates in bronchial biopsies from participants with asthma, particularly in neutrophilic asthma. In conclusion, these results suggest that ER stress primes TSLP that is then enhanced further upon TLR3 activation, which may induce severe asthma exacerbations. Targeting ER stress using pharmacological interventions may provide novel therapeutics for severe uncontrolled asthma.NEW & NOTEWORTHY TSLP is an epithelial-derived cytokine and a key regulator in the pathogenesis of severe uncontrolled asthma. We demonstrate a novel mechanism by which endoplasmic reticulum stress signaling upregulates airway epithelial TSLP mRNA expression via the PERK-CHOP signaling pathway and enhances TLR3-mediated TSLP protein secretion.

ITGAM-macrophage modulation as a potential strategy for treating neutrophilic Asthma: insights from bioinformatics analysis and in vivo experiments

Identification of molecular biomarkers associated with neutrophilic asthma (NA) phenotype may inform the discovery of novel pathobiological mechanisms and the development of diagnostic markers. Three mRNA transcriptome datasets extracted from induced sputum of asthma patients with various inflammatory types were used to screen for macrophage-related molecular mechanisms and targets in NA. Furthermore, the predicted targets were also validated on an independent dataset (N = 3) and animal model (N = 5). A significant increase in total cells, neutrophils and macrophages was observed in bronchoalveolar lavage (BAL) fluid of NA mice induced by ovalbumin/freund's adjuvant, complete (OVA/CFA). And we also found elevated levels of neutrophil and macrophage infiltration in NA subtype in external datasets. NA mice had increased secretion of IgE, IL-1β, TNF-α and IL-6 in serum and BAL fluid. MPO, an enzyme present in neutrophils, was also highly expressed in NA mice. Then, weighted gene co-expression network analysis (WGCNA) identified 684 targets with the strongest correlation with NA, and we obtained 609 macrophage-related specific differentially expressed genes (DEGs) in NA by integrating macrophage-related genes. The top 10 genes with high degree values were obtained and their mRNA levels and diagnostic performance were then determined by RT-qPCR and receiver operator characteristic (ROC) analysis. Statistically significant correlations were found between macrophages and all key targets, with the strongest correlation between ITGAM and macrophages in NA. Double-Immunofluorescence staining further confirmed the co-localization of ITGAM and F4/80 in NA. ITGAM was identified as a critical target to distinguish NA from healthy/non-NA individuals, which may provide a novel avenue to further uncover the mechanisms and therapy of NA.

Inhibition of γ-glutamyl transferase suppresses airway hyperresponsiveness and airway inflammation in a mouse model of steroid resistant asthma exacerbation

Introduction

Despite recent advances, there are limited treatments available for acute asthma exacerbations. Here, we investigated the therapeutic potential of GGsTop, a γ-glutamyl transferase inhibitor, on the disease with a murine model of asthma exacerbation.

Methods

GGsTop was administered to mice that received lipopolysaccharide (LPS) and ovalbumin (OVA) challenges. Airway hyperresponsiveness (AHR), lung histology, mucus hypersecretion, and collagen deposition were analyzed to evaluate the hallmark features of asthma exacerbation. The level of proinflammatory cytokines and glutathione were determined with/without GGsTop. The transcription profiles were also examined.

Results

GGsTop attenuates hallmark features of the disease with a murine model of LPS and OVA driven asthma exacerbation. Airway hyperresponsiveness (AHR), mucus hypersecretion, collagen deposition, and expression of inflammatory cytokines were dramatically inhibited by GGsTop treatment. Additionally, GGsTop restored the level of glutathione. Using RNA-sequencing and pathway analysis, we demonstrated that the activation of LPS/NFκB signaling pathway in airway was downregulated by GGsTop. Interestingly, further analysis revealed that GGsTop significantly inhibited not only IFNγ responses but also the expression of glucocorticoid-associated molecules, implicating that GGsTop profoundly attenuates inflammatory pathways.

Conclusions

Our study suggests that GGsTop is a viable treatment for asthma exacerbation by broadly inhibiting the activation of multiple inflammatory pathways.

Large-scale antibody immune response mapping of splenic B cells and bone marrow plasma cells in a transgenic mouse model

Molecular characterization of antibody immunity and human antibody discovery is mainly carried out using peripheral memory B cells, and occasionally plasmablasts, that express B cell receptors (BCRs) on their cell surface. Despite the importance of plasma cells (PCs) as the dominant source of circulating antibodies in serum, PCs are rarely utilized because they do not express surface BCRs and cannot be analyzed using antigen-based fluorescence-activated cell sorting. Here, we studied the antibodies encoded by the entire mature B cell populations, including PCs, and compared the antibody repertoires of bone marrow and spleen compartments elicited by immunization in a human immunoglobulin transgenic mouse strain. To circumvent prior technical limitations for analysis of plasma cells, we applied single-cell antibody heavy and light chain gene capture from the entire mature B cell repertoires followed by yeast display functional analysis using a cytokine as a model immunogen. We performed affinity-based sorting of antibody yeast display libraries and large-scale next-generation sequencing analyses to follow antibody lineage performance, with experimental validation of 76 monoclonal antibodies against the cytokine antigen that identified three antibodies with exquisite double-digit picomolar binding affinity. We observed that spleen B cell populations generated higher affinity antibodies compared to bone marrow PCs and that antigen-specific splenic B cells had higher average levels of somatic hypermutation. A degree of clonal overlap was also observed between bone marrow and spleen antibody repertoires, indicating common origins of certain clones across lymphoid compartments. These data demonstrate a new capacity to functionally analyze antigen-specific B cell populations of different lymphoid organs, including PCs, for high-affinity antibody discovery and detailed fundamental studies of antibody immunity.

The Role of IL-33/ST2 in COPD and Its Future as an Antibody Therapy

COPD is a leading cause of mortality and morbidity worldwide and is associated with a high socioeconomic burden. Current treatment includes the use of inhaled corticosteroids and bronchodilators, which can help to improve symptoms and reduce exacerbations; however, there is no solution for restoring lung function and the emphysema caused by loss of the alveolar tissue. Moreover, exacerbations accelerate progression and challenge even more the management of COPD. Mechanisms of inflammation in COPD have been investigated over the past years, thus opening new avenues to develop novel targeted-directed therapies. Special attention has been paid to IL-33 and its receptor ST2, as they have been found to mediate immune responses and alveolar damage, and their expression is upregulated in COPD patients, which correlates with disease progression. Here we summarize the current knowledge on the IL-33/ST2 pathway and its involvement in COPD, with a special focus on developed antibodies and the ongoing clinical trials using anti-IL-33 and anti-ST2 strategies in COPD patients.

Extracellular Vesicles in Inner Ear Therapies-Pathophysiological, Manufacturing, and Clinical Considerations

(1) Background: Sensorineural hearing loss is a common and debilitating condition. To date, comprehensive pharmacologic interventions are not available. The complex and diverse molecular pathology that underlies hearing loss may limit our ability to intervene with small molecules. The current review foccusses on the potential for the use of extracellular vesicles in neurotology. (2) Methods: Narrative literature review. (3) Results: Extracellular vesicles provide an opportunity to modulate a wide range of pathologic and physiologic pathways and can be manufactured under GMP conditions allowing for their application in the human inner ear. The role of inflammation in hearing loss with a focus on cochlear implantation is shown. How extracellular vesicles may provide a therapeutic option for complex inflammatory disorders of the inner ear is discussed. Additionally, manufacturing and regulatory issues that need to be addressed to develop EVs as advanced therapy medicinal product for use in the inner ear are outlined. (4) Conclusion: Given the complexities of inner ear injury, novel therapeutics such as extracellular vesicles could provide a means to modulate inflammation, stress pathways and apoptosis in the inner ear.

Adeno-associated virus-mediated IL-12 gene expression alleviates lung inflammation and Th2-responses in OVA-sensitized asthmatic mice

High levels of allergen exposure increase the prevalence of asthma in development countries. The asthmatic Th2 response is characterized with high eosinophil infiltration, elevated Th2 cytokines and IgE secretion resulting in local or systemic inflammation. However, the treatment with palliative Th2 inhibitor drugs can't completely control asthma and that is why the development of novel approaches is still important. Based on Th1 and Th2 immune homeostasis, the enhanced Th1 immune response has high potential to alleviate Th2 immune response. Thus, we aimed to overexpress single chain IL-12 (scIL-12) via recombinant adeno-associated virus (rAAV) vector (as rAAV-IL-12) and test the efficacy in an ovalbumin (OVA)-induced asthmatic murine model. We firstly demonstrated the bioactivity of exogenous scIL-12. The expression of exogenous scIL-12 was also detected in the lungs of rAAV-IL-12 transduced mice. The data demonstrated that overexpression of exogenous scIL-12 significantly suppressed total cell numbers and eosinophil infiltration, as well as the mucus secretion in rAAV-IL-12-treated mice. The decreased OVA-specific IgE in bronchoalveolar lavage fluid (BALF) and gene expression of Th2-cytokines or CCL11 in lung were observed. In addition, the production of cytokines in the supernatants of OVA-stimulated splenocytes was suppressed with rAAV-IL-12 treatment. Thus, scIL-12 expression by rAAV vector was able to modulate Th2 activity and has the potential to be developed as a feasible strategy in modulating allergic diseases.

Nuclear receptor Nr1d1 alleviates asthma by abating GATA3 gene expression and Th2 cell differentiation

Nuclear receptors are a unique family of transcription factors that play cardinal roles in physiology and plethora of human diseases. The adopted orphan nuclear receptor Nr1d1 is a constitutive transcriptional repressor known to modulate several biological processes. In this study, we found that Nr1d1 plays a decisive role in T helper (Th)-cell polarization and transcriptionally impedes the formation of Th2 cells by directly binding to the promoter region of GATA binding protein 3 (GATA3) gene. Nr1d1 interacts with its cellular companion, the nuclear receptor corepressor and histone deacetylase 3 to form a stable repression complex on the GATA3 promoter. The presence of Nr1d1 also imparts protection against associated inflammatory responses in murine model of asthma and its ligand SR9011 eased disease severity by suppressing Th2 responses. Moreover, Chip-seq profiling uncovered Nr1d1 interactions with other gene subsets that impedes Th2-linked pathways and regulates metabolism, immunity and brain functions, therefore, providing empirical evidence regarding the genetic link between asthma and other comorbid conditions. Thus, Nr1d1 emerges as a molecular switch that could be targeted to subdue asthma.

TFR1 expression in induced sputum is associated with asthma severity

Background

Asthma is characterized as a chronic inflammatory airway disease. Iron accumulation is related to asthma pathogenesis. Transferrin receptor 1(TFR1) expression is associated with intracellular iron overload in macrophages. In our study, we explored the association among TFR1 expression, the inflammatory macrophage phenotype, and asthma severity.

Methods

Induced sputum was collected from 50 asthma patients. Real-time PCR was used to evaluate mRNA expression. The status of inflammatory macrophage phenotype was assessed using flow cytometry.

Results

TFR1 levels were inversely correlated with forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) and FEV₁/vital capacity (VC). Among inflammatory cytokines, TFR1 expression was positively correlated with IL-1β, TNF-α, IL-6, IFN-γ, and IL-17A mRNA expression in induced sputum. Moreover, TFR1 expression was positively correlated with the number of proinflammatory M1 macrophages and iNOS expression in induced sputum. Neutrophil counts in induced sputum were significantly and positively related to TFR1 expression. Furthermore, TFR1 expression showed an increasing trend in asthma patients with no family history. Our findings indicated that TFR1 expression was consistent with the asthma severity index, especially the proinflammatory M1 macrophage phenotype. TFR1 expression may be a good marker to indicate asthma severity.

Inhibition of Spleen Tyrosine Kinase Restores Glucocorticoid Sensitivity to Improve Steroid-Resistant Asthma

Background: Regulation or restoration of therapeutic sensitivity to glucocorticoids is important in patients with steroid-resistant asthma. Spleen tyrosine kinase (Syk) is activated at high levels in asthma patients and mouse models, and small-molecule Syk inhibitors such as R406 show potent anti-inflammatory effects in the treatment of immune inflammatory diseases. Several downstream signaling molecules of Syk are involved in the glucocorticoid response, so we hypothesized that R406 could restore sensitivity to dexamethasone in severe steroid-resistant asthma.

Objective: To discover the role of the Syk inhibitor R406 in glucocorticoid resistance in severe asthma.

Methods: Steroid-resistant asthma models were induced by exposure of C57BL/6 mice to house dust mite (HDM) and β-glucan and by TNF-α administration to the bronchial epithelial cell line BEAS-2B. We evaluated the role of the Syk inhibitor R406 in dexamethasone (Dex)-insensitive airway inflammation. Pathological alterations and cytokines in the lung tissues and inflammatory cells in BALF were assessed. We examined the effects of Dex or R406 alone and in combination on the phosphorylation of MAPKs, glucocorticoid receptor (GR) and Syk, as well as the transactivation and transrepression induced by Dex in mouse lung tissues and BEAS-2B cells.

Results: Exposure to HDM and β-glucan induced steroid-resistant airway inflammation. The Syk inhibitor R406 plus Dex significantly reduced airway inflammation compared with Dex alone. Additionally, TNF-α-induced IL-8 production in BEAS-2B cells was not completely inhibited by Dex, while R406 markedly promoted the anti-inflammatory effect of Dex. Compared with Dex alone, R406 enhanced Dex-mediated inhibition of the phosphorylation of MAPKs and GR-Ser226 induced by allergens or TNF-α in vivo and in vitro. Moreover, R406 also restored the impaired expression and nuclear translocation of GRα induced by TNF-α. Then, the activation of NF-κB and decreased HDAC2 activity in the asthmatic model were further regulated by R406, as well as the expression of GILZ.

Conclusions: The Syk inhibitor R406 improves sensitivity to dexamethasone by modulating GR. This study provides a reference for the development of drugs to treat severe steroid-resistant asthma.

The link between atopic dermatitis and asthma- immunological imbalance and beyond

Atopic diseases are multifactorial chronic disturbances which may evolve one into another and have overlapping pathogenetic mechanisms. Atopic dermatitis is in most cases the first step towards the development of the atopic march and represents a major socio-economic burden in the industrialized countries. The treatment of atopic diseases is often long-lasting and in some cases with lower effectiveness than expected.

In order to prevent the development of the atopic march, the links between the atopic diseases have to be understood. The aim of this review is to present some major points outlining the link between atopic dermatitis and asthma, through a research in the medical literature from recent years.

Stratifying patient populations according to the clinical phenotype of their disease and according to specific measurable values (biomarkers) can help to establish the main etiopathogenetic mechanisms of the disease in these populations. This will add predictive value for the evolution of the disease, and will allow the use and research of more targeted therapy in order to stop this evolution and comorbidities.

Development of Neutralizing Multimeric Nanobody Constructs Directed against IL-13: From Immunization to Lead Optimization

IL-13 is a pleiotropic cytokine mainly secreted by Th2 cells. It reacts with many different types of cells involved in allergy, inflammation, and fibrosis, e.g., mastocytes, B cells, and fibroblasts. The role of IL-13 in conditions involving one or several of these phenotypes has therefore been extensively investigated. The inhibition of this cytokine in animal models for various pathologies yielded highly promising results. However, most human trials relying on anti-IL-13 conventional mAbs have failed to achieve a significant improvement of the envisaged disorders. Where some studies might have suffered from several weaknesses, the strategies themselves, such as targeting only IL-13 using conventional mAbs or employing a systemic administration, could be questioned. Nanobodies are recombinant Ag-binding fragments derived from the variable part of H chain-only Abs occurring in Camelidae. Thanks to their single-domain structure, small size (≈15 kDa), good stability, and solubility, they can be engineered into multispecific constructs for combined therapies or for use in new strategies such as formulations for local administration, e.g., pulmonary administration. In this study, we describe the generation of 38 nanobodies that can be subdivided into five CDR3 families. Nine nanobodies were found to have a good affinity profile (K_D = 1-200 nM), but none were able to strongly inhibit IL-13 biological activity in vitro (IC₅₀ > 50 µM: HEK-Blue IL-13/IL-4 cells). Multimeric constructs were therefore designed from these inhibitors and resulted in an up to 36-fold improvement in affinity and up to 300-fold enhancement of the biological activity while conserving a high specificity toward IL-13.

From Biomarkers to Novel Therapeutic Approaches in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous and complex disorder. In this review, we provided a comprehensive overview of biomarkers involved in COPD, and potential novel biological therapies that may provide additional therapeutic options for COPD. The complex characteristics of COPD have made the recommendation of a generalized therapy challenging, suggesting that a tailored, personalized strategy may lead to better outcomes. Existing and unmet needs for COPD treatment support the continued development of biological therapies, including additional investigations into the potential clinical applications of this approach.

New Insights into the Role of PD-1 and Its Ligands in Allergic Disease

Programmed cell death 1 (PD-1) and its ligands PD-L1 and PD-L2 are receptors that act in co-stimulatory and coinhibitory immune responses. Signaling the PD-1/PD-L1 or PD-L2 pathway is essential to regulate the inflammatory responses to infections, autoimmunity, and allergies, and it has been extensively studied in cancer. Allergic diseases include asthma, rhinoconjunctivitis, atopic dermatitis, drug allergy, and anaphylaxis. These overactive immune responses involve IgE-dependent activation and increased CD4+ T helper type 2 (Th2) lymphocytes. Recent studies have shown that PD-L1 and PD-L2 act to regulate T-cell activation and function. However, the main role of PD-1 and its ligands is to balance the immune response; however, the inflammatory process of allergic diseases is poorly understood. These immune checkpoint molecules can function as a brake or a kick-start to regulate the adaptive immune response. These findings suggest that PD-1 and its ligands may be a key factor in studying the exaggerated response in hypersensitivity reactions in allergies. This review summarizes the current understanding of the role of PD-1 and PD-L1 and PD-L2 pathway regulation in allergic diseases and how this immunomodulatory pathway is currently being targeted to develop novel therapeutic immunotherapy.

The magnitude of airway remodeling is not altered by distinct allergic inflammatory responses in BALB/c versus C57BL/6 mice but matrix composition differs

Allergic airway inflammation is heterogeneous with variability in immune phenotypes observed across asthmatic patients. Inflammation has been thought to directly contribute to airway remodeling in asthma, but clinical data suggest that neutralizing type 2 cytokines does not necessarily alter disease pathogenesis. Here, we utilized C57BL/6 and BALB/c mice to investigate the development of allergic airway inflammation and remodeling. Exposure to an allergen cocktail for up to 8 weeks led to type 2 and type 17 inflammation, characterized by airway eosinophilia and neutrophilia and increased expression of chitinase-like proteins in both C57BL/6 and BALB/c mice. However, BALB/c mice developed much greater inflammatory responses than C57BL/6 mice, effects possibly explained by a failure to induce pathways that regulate and maintain T-cell activation in C57BL/6 mice, as shown by whole lung RNA transcript analysis. Allergen administration resulted in a similar degree of airway remodeling between mouse strains but with differences in collagen subtype composition. Increased collagen III was observed around the airways of C57BL/6 but not BALB/c mice while allergen-induced loss of basement membrane collagen IV was only observed in BALB/c mice. This study highlights a model of type 2/type 17 airway inflammation in mice whereby development of airway remodeling can occur in both BALB/c and C57BL/6 mice despite differences in immune response dynamics between strains. Importantly, compositional changes in the extracellular matrix between genetic strains of mice may help us better understand the relationships between lung function, remodeling and airway inflammation.

CpG oligodeoxynucleotides attenuate RORγt-mediated Th17 response by restoring histone deacetylase-2 in cigarette smoke-exposure asthma

BACKGROUND

Cigarette smoke (CS) exposure increases corticosteroid insensitive asthma related to increased Th17 phenotype, and new treatment strategies are needed for CS-associated asthma. Histone deacetylase 2 (HDAC2), found in the airway epithelium, is critical for ameliorating glucocorticoids insensitivity. We recently demonstrated the anti-inflammatory effects of CpG oligodeoxynucleotides (CpG-ODNs) on CS-exposure asthma. However, the effects of CpG-ODNs on HDAC2 expression and enzymatic activity remain unclear. This study aimed to assess whether CpG-ODNs protect against excessive Th17 immune responses in CS-induced asthma through HDAC2-dependent mechanisms and compared their effects with those of corticosteroids.

METHODS

The effects of CpG-ODNs alone and in combination with budesonide (BUD) on airway inflammation and Th2/Th17-related airway immune responses were determined using an in vivo model of CS-induced asthma and in cultured bronchial epithelial (HBE) cells administered ovalbumin (OVA) and/or cigarette smoke extract (CSE). HDAC2 and retinoid-related orphan nuclear receptor γt (RORγt) expression were also assessed in mouse lung specimens and HBE cells.

RESULTS

CpG-ODNs and BUD synergistically attenuated CS exposure asthmatic responses in vivo by modulating the influx of eosinophils and neutrophils, airway remodeling, Th2/Th17 associated cytokine and chemokine production, and airway hyperresponsiveness and blocking RORγt-mediated Th17 inflammation through induced HDAC2 expression/activity. In vitro, CpG-ODNs synergized with BUD to inhibit Th17 cytokine production in OVA- and CSE-challenged HBE cells while suppressing RORγt and increasing epithelial HDAC2 expression/activity.

CONCLUSIONS

CpG-ODNs reversed CS-induced HDAC2 downregulation and enhanced the sensitivity of CS-exposed asthmatic mice and CSE-induced HBE cells to glucocorticoid treatment. This effect may be associated with HDAC2 restoration via RORγt/IL-17 pathway regulation, suggesting that CpG-ODNs are potential corticosteroid-sparing agents for use in CS-induced asthma with Th17-biased immune conditions.

MicroRNA miR-146a-5p inhibits the inflammatory response and injury of airway epithelial cells via targeting TNF receptor-associated factor 6

Bronchial asthma is a common respiratory disease, which is characterized by airway inflammation, remodeling and hyperresponsiveness. MicroRNAs (miRNAs), as reported, are implicated in the pathogenesis of many diseases, but how miRNAs-146a-5p (miR-146a-5p) works in asthma remains inconclusive. In this work, we proved that miR-146a-5p expression was inhibited in asthma patients’ plasma and platelet activating factor (PAF)-induced human small airway epithelial cells (HSAECs). MiR-146a-5p up-regulation ameliorated the inflammatory reaction and cell barrier damage of HSAECs induced by PAF, and inhibited the apoptosis; besides, miR-146a-5p down-regulation functioned oppositely. In addition, miR-146a-5p could target TNF receptor-associated factor 6 (TRAF6) and negatively regulate its expression. TRAF6 overexpression could counterract the impact of miR-146a-5p up-regulation on PAF-induced inflammation, cell barrier damage and apoptosis of HSAECs. Collectively, miR-146a-5p may protect airway epithelial cells and inhibit the pathogenesis of asthma via targeting TRAF6.

Abnormal iron status is independently associated with reduced oscillometric lung function in schoolchildren

BACKGROUND

Associations between anemia and allergic diseases have been reported, but the relationship of iron deficiency with airway dysfunction in children remains unclear. We aimed to investigate the relationship between abnormal iron parameters and lung function in schoolchildren.

METHODS

Four hundred and forty-five children (10-12 years-old) from 11 elementary schools in were enrolled. The relationships of different iron parameters (hemoglobin, serum iron, transferrin saturation, and serum ferritin) with lung function evaluated by impulse oscillometry (airways resistance at 5 Hz [Rrs5], 10 Hz [Rrs10], and the difference of Rrs5 and Rrs20 Hz [Rrs5-20]), and with exhaled nitric oxide (FeNO) were evaluated after adjustment for confounders including height, sex, and body mass index z-score, and for additional covariates that could affect airway function.

RESULTS

Total airway dysfunction represented by Rrs5 was reduced in participants with low serum iron level (aβ: -0.13, 95% CI: -0.23 to -0.03, p = 0.040) after adjustment for key confounders, but did not correlate with other iron profiles. Reduced oscillometric lung function recorded as Rrs5-20 was related with low serum iron and high serum ferritin, but the results were inconsistent after multiple comparisons. Associations were not observed with serum hemoglobin.

CONCLUSIONS

Decreased serum iron level was related with airway dysfunction represented as oscillomteric Rrs5. Our results suggest a relationship of reduced lung function with abnormal iron status in children.

Proteome profiling reveals the efficacy and targets of sophocarpine against asthma

Sophocarpine (SPC) as a quinolizidine alkaloid displays powerful effects on inflammatory diseases through regulating multiple targets. Asthma is a complex heterogeneous and inflammatory disease with an increasing incidence worldwide. Here we established a mice asthma model and investigated the effect of SPC. Mice induced by ovalbumin (OVA) exhibits exacerbated Th1/Th2 immune imbalance and allergic lung inflammation. SPC treatment regulated Th1/Th2 cytokines production (IL-4, IL-5 and INF-γ) in BALF, reduced IgE level in serum, inhibited inflammatory cell infiltration, and improved the lung tissue pathology. Proteomic results showed that 5064 proteins in lung tissue were detected and among them 223 preliminary therapeutic targets of SPC were selected. Subsequently, excluding non-human genes, 109 targets with established crystal structures were harvested. Meanwhile, the molecular docking results showed that the binding energy of 87 targets with SPC was varied from -9.72 kcal/mol to 227.16 kcal/mol. Further, SPC suppressed arrb2, anxa1, myd88 and sphk1 expression and activated p-stat1. All of the five targets based on the screened results of proteomics and molecular docking are critical in allergic asthma. Thus, our data revealed that SPC alleviated bronchial asthma via targeting multi-targets.

The central role of IL-33/IL-1RL1 pathway in asthma: From pathogenesis to intervention

Interleukin-33 (IL-33), a member of the IL-1 family, and its cognate receptor, Interleukin-1 receptor like-1 (IL-1RL1 or ST2), are susceptibility genes for childhood asthma. In response to cellular damage, IL-33 is released from barrier tissues as an 'alarmin' to activate the innate immune response. IL-33 drives type 2 responses by inducing signalling through its receptor IL-1RL1 in several immune and structural cells, thereby leading to type 2 cytokine and chemokine production. IL-1RL1 gene transcript encodes different isoforms generated through alternative splicing. Its soluble isoform, IL-1RL1-a or sST2, acts as a decoy receptor by sequestering IL-33, thereby inhibiting IL1RL1-b/IL-33 signalling. IL-33 and its receptor IL-1RL1 are therefore considered as putative biomarkers or targets for pharmacological intervention in asthma. This review will provide an overview of the genetics and biology of the IL-33/IL-1RL1 pathway in the context of asthma pathogenesis. It will discuss the potential and complexities of targeting the cytokine or its receptor, how genetics or biomarkers may inform precision medicine for asthma targeting this pathway, and the possible positioning of therapeutics targeting IL-33 or its receptor in the expanding landscape of novel biologicals applied in asthma management.

Therapeutic targets in lung tissue remodelling and fibrosis

Structural changes involving tissue remodelling and fibrosis are major features of many pulmonary diseases, including asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Abnormal deposition of extracellular matrix (ECM) proteins is a key factor in the development of tissue remodelling that results in symptoms and impaired lung function in these diseases. Tissue remodelling in the lungs is complex and differs between compartments. Some pathways are common but tissue remodelling around the airways and in the parenchyma have different morphologies. Hence it is critical to evaluate both common fibrotic pathways and those that are specific to different compartments; thereby expanding the understanding of the pathogenesis of fibrosis and remodelling in the airways and parenchyma in asthma, COPD and IPF with a view to developing therapeutic strategies for each. Here we review the current understanding of remodelling features and underlying mechanisms in these major respiratory diseases. The differences and similarities of remodelling are used to highlight potential common therapeutic targets and strategies. One central pathway in remodelling processes involves transforming growth factor (TGF)-β induced fibroblast activation and myofibroblast differentiation that increases ECM production. The current treatments and clinical trials targeting remodelling are described, as well as potential future directions. These endeavours are indicative of the renewed effort and optimism for drug discovery targeting tissue remodelling and fibrosis.

Exosomes from human umbilical cord mesenchymal stem cells attenuate the inflammation of severe steroid-resistant asthma by reshaping macrophage polarization

BACKGROUND

Severe, steroid-resistant asthma (SSRA) is a serious clinical problem in asthma management. Affected patients have severe clinical symptoms, worsened quality of life, and do not respond to steroid, a mainstay steroid treatment of asthma. Thus, effective therapies are urgently needed. Exosomes derived from mesenchymal stem cell (MSC-Exo) has become attractive candidates for the lung inflammatory diseases through its immunomodulatory effects. In this study, we explored the therapeutic effects of MSC-Exo in SSRA and identified the therapeutic mechanism of MSC-Exo.

METHOD

Exosomes from human umbilical cord mesenchymal stem cell (hUCMSC) were isolated and characterized by transmission electron microscopy, nanoparticle tracking analysis and flow cytometry analysis. Effects of MSC-Exo on airway hyper responsiveness (AHR), inflammation, histopathology, and macrophage polarization in SSRA in mice were evaluated. Systematic depletion of macrophages determined the role of macrophages in the therapeutic effect of SSRA in mice. LPS-stimulated RAW 264.7 cell model was constructed to determine the underlying mechanism of MSC-Exo on macrophage polarization. qRT-PCR, Western blotting, immunofluorescence, and flow cytometry were performed to evaluate the expression of M1 or M2 markers. Tandem mass tags (TMT)-labeled quantitative proteomics were applied to explore the central protein during the regulation effect of MSC-Exo on macrophage polarization. Knockdown and overexpression of TRAF1 were used to further clarify the role of the central protein on macrophage polarization.

RESULT

We successfully isolated and characterized exosomes from hUCMSCs. We verified that the intratracheal administration of MSC-Exo reversed AHR, histopathology changes, and inflammation in SSRA mice. Systematic depletion of macrophages weakened the therapeutic effect of MSC-Exo. We found that MSC-Exo treatment inhibited M1 polarization and promoted M2 polarization in LPS-stimulated RAW 264.7 cells. Subsequently, tumor necrosis factor receptor-associated factor 1 (TRAF1) was determined as the central protein which may be closely related to the regulation of macrophage polarization from TMT-labeled quantitative proteomics analysis. Knockdown and overexpression of TRAF1 demonstrated that the effect of MSC-Exo treatment on macrophage polarization, NF-κB and PI3K/AKT signaling was dependent on TRAF1.

CONCLUSION

MSC-Exo can ameliorate SSRA by moderating inflammation, which is achieved by reshaping macrophage polarization via inhibition of TRAF1.

The Therapeutic Effect of Extracellular Vesicles on Asthma in Pre-Clinical Models: A Systematic Review Protocol

Asthma is the most common pediatric disease, characterized by chronic airway inflammation and airway hyperresponsiveness. There are several management options for asthma, but no specific treatment. Extracellular vesicles (EVs) are powerful cellular mediators of endocrine, autocrine and paracrine signalling, and can modulate biophysiological function in vitro and in vivo. A thorough investigation of therapeutic effects of EVs in asthma has not been conducted. Therefore, this systematic review is designed to synthesize recent literature on the therapeutic effects of EVs on physiological and biological outcomes of asthma in pre-clinical studies. An electronic search of Web of Science, EMBASE, MEDLINE, and Scopus will be conducted on manuscripts published in the last five years that adhere to standardized guidelines for EV research. Grey literature will also be included. Two reviewers will independently screen the selected studies for title and abstract, and full text based on the eligibility criteria. Data will be extracted, narratively synthesized and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. This systematic review will summarize the current knowledge from preclinical studies investigating the therapeutic effects of EVs on asthma. The results will delineate whether EVs can mitigate biological hallmarks of asthma, and if so, describe the underlying mechanisms involved in the process. This insight is crucial for identifying key pathways that can be targeted to alleviate the burden of asthma. The data will also reveal the origin, dosage and biophysical characteristics of beneficial EVs. Overall, our results will provide a scaffold for future intervention and translational studies on asthma treatment.

Asthma-COPD overlap: current understanding and the utility of experimental models

Pathological features of both asthma and COPD coexist in some patients and this is termed asthma-COPD overlap (ACO). ACO is heterogeneous and patients exhibit various combinations of asthma and COPD features, making it difficult to characterise the underlying pathogenic mechanisms. There are no controlled studies that define effective therapies for ACO, which arises from the lack of international consensus on the definition and diagnostic criteria for ACO, as well as scant in vitro and in vivo data. There remain unmet needs for experimental models of ACO that accurately recapitulate the hallmark features of ACO in patients. The development and interrogation of such models will identify underlying disease-causing mechanisms, as well as enabling the identification of novel therapeutic targets and providing a platform for assessing new ACO therapies. Here, we review the current understanding of the clinical features of ACO and highlight the approaches that are best suited for developing representative experimental models of ACO.

Understanding the pathogenesis of asthma-COPD overlap is critical for improving therapeutic approaches. We present current knowledge on asthma-COPD overlap and the requirements for developing an optimal animal model of disease.https://bit.ly/3lsjyvm

Human β-defensin-2 suppresses key features of asthma in murine models of allergic airways disease

BACKGROUND

Asthma is an airway inflammatory disease and a major health problem worldwide. Anti-inflammatory steroids and bronchodilators are the gold-standard therapy for asthma. However, they do not prevent the development of the disease, and critically, a subset of asthmatics are resistant to steroid therapy.

OBJECTIVE

To elucidate the therapeutic potential of human β-defensins (hBD), such as hBD2 mild to moderate and severe asthma.

METHODS

We investigated the role of hBD2 in a steroid-sensitive, house dust mite-induced allergic airways disease (AAD) model and a steroid-insensitive model combining ovalbumin-induced AAD with C muridarum (Cmu) respiratory infection.

RESULTS

In both models, we demonstrated that therapeutic intranasal application of hBD2 significantly reduced the influx of inflammatory cells into the bronchoalveolar lavage fluid. Furthermore, key type 2 asthma-related cytokines IL-9 and IL-13, as well as additional immunomodulating cytokines, were significantly decreased after administration of hBD2 in the steroid-sensitive model. The suppression of inflammation was associated with improvements in airway physiology and treatment also suppressed airway hyper-responsiveness (AHR) in terms of airway resistance and compliance to methacholine challenge.

CONCLUSIONS AND CLINICAL RELEVANCE

These data indicate that hBD2 reduces the hallmark features and has potential as a new therapeutic agent in allergic and especially steroid-resistant asthma.

Emerging concepts and directed therapeutics for the management of asthma: regulating the regulators

Asthma is a common, heterogeneous and serious disease, its prevalence has steadily risen in most parts of the world, and the condition is often inadequately controlled in many patients. Hence, there is a major need for new therapeutic approaches. Mild-to-moderate asthma is considered a T-helper cell type-2-mediated inflammatory disorder that develops due to abnormal immune responses to otherwise innocuous allergens. Prolonged exposure to allergens and persistent inflammation results in myofibroblast infiltration and airway remodelling with mucus hypersecretion, airway smooth muscle hypertrophy, and excess collagen deposition. The airways become hyper-responsive to provocation resulting in the characteristic wheezing and obstructed airflow experienced by patients. Extensive research has progressed the understanding of the underlying mechanisms and the development of new treatments for the management of asthma. Here, we review the basis of the disease, covering new areas such as the role of vascularisation and microRNAs, as well as associated potential therapeutic interventions utilising reports from animal and human studies. We also cover novel drug delivery strategies that are being developed to enhance therapeutic efficacy and patient compliance. Potential avenues to explore to improve the future of asthma management are highlighted.

Antisense Oligonucleotides Targeting Jagged 1 Reduce House Dust Mite-induced Goblet Cell Metaplasia in the Adult Murine Lung

Goblet cell metaplasia, excessive mucus production, and inadequate mucus clearance accompany and exacerbate multiple chronic respiratory disorders, such as asthma and chronic obstructive pulmonary disease. Notch signaling plays a central role in controlling the fate of multiple cell types in the lung, including goblet cells. In the present study, we explored the therapeutic potential of modulating the Notch pathway in the adult murine lung using chemically modified antisense oligonucleotides (ASOs). To this end, we designed and characterized ASOs targeting the Notch receptors Notch1, Notch2, and Notch3 and the Notch ligands Jag1 (Jagged 1) and Jag2 (Jagged 2). Pulmonary delivery of ASOs in healthy mice or mice exposed to house dust mite, a commonly used mouse model of asthma, resulted in a significant reduction of the respective mRNAs in the lung. Furthermore, ASO-mediated knockdown of Jag1 or Notch2 in the lungs of healthy adult mice led to the downregulation of the club cell marker Scgb1a1 and the concomitant upregulation of the ciliated cell marker FoxJ1 (forkhead box J1). Similarly, ASO-mediated knockdown of Jag1 or Notch2 in the house dust mite disease model led to reduced goblet cell metaplasia and decreased mucus production. Because goblet cell metaplasia and excessive mucus secretion are a common basis for many lung pathologies, we propose that ASO-mediated inhibition of JAG1 could provide a novel therapeutic path for the treatment of multiple chronic respiratory diseases.

Role of Lung Microbiome in Innate Immune Response Associated With Chronic Lung Diseases

Respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), lung fibrosis, and lung cancer, pose a huge socio-economic burden on society and are one of the leading causes of death worldwide. In the past, culture-dependent techniques could not detect bacteria in the lungs, therefore the lungs were considered a sterile environment. However, the development of culture-independent techniques, particularly 16S rRNA sequencing, allowed for the detection of commensal microbes in the lung and with further investigation, their roles in disease have since emerged. In healthy individuals, the predominant commensal microbes are of phylum Firmicutes and Bacteroidetes, including those of the genera Veillonella and Prevotella. In contrast, pathogenic microbes (Haemophilus, Streptococcus, Klebsiella, Pseudomonas) are often associated with lung diseases. There is growing evidence that microbial metabolites, structural components, and toxins from pathogenic and opportunistic bacteria have the capacity to stimulate both innate and adaptive immune responses, and therefore can contribute to the pathogenesis of lung diseases. Here we review the multiple mechanisms that are altered by pathogenic microbiomes in asthma, COPD, lung cancer, and lung fibrosis. Furthermore, we focus on the recent exciting advancements in therapies that can be used to restore altered microbiomes in the lungs.

Emerging therapeutic targets and preclinical models for severe asthma

INTRODUCTION

Asthma is a heterogeneous disease with complex multifactorial causes. It is possible to subclassify asthma into different phenotypes that have distinct immunological features. Eosinophilic asthma is a well-known phenotype of severe asthma; however, a large body of clinical and experimental evidence strongly associates persistent airway inflammation, including the accumulation of neutrophils in the bronchial mucosa, and resistance to corticosteroid therapy and non-Type-2 immune responses with severe asthma. Importantly, mainstay therapies are often ineffective in severe asthma and effective alternatives are urgently needed.

AREAS COVERED

Here, we discussed recently developed mouse models of severe asthma that recapitulates key features of the disease in humans. We also provide findings from clinically relevant experimental models that have identified potential therapeutic targets for severe asthma. The most relevant publications on the topic of interest were selected from PubMed.

EXPERT COMMENTARY

Increasing the understanding of disease-causing mechanisms in severe asthma may lead to the identification of novel therapeutic targets and the development of more effective therapies. Intense research interest into investigating the pathophysiological mechanisms of severe asthma has driven the development and interrogation of a myriad of mouse models that aim to replicate hallmark features of severe asthma in humans.

Update on the role of endoplasmic reticulum stress in asthma

Asthma has long attracted extensive attention because of its recurring symptoms of reversible airflow obstruction, airway hyperresponsiveness (AHR) and airway inflammation. Although accumulating evidence has enabled gradual increases in understanding of the pathogenesis of asthma, many questions regarding the mechanisms underlying asthma onset and progression remain unanswered. Recent advances delineating the potential functions of endoplasmic reticulum (ER) stress in meeting the need for an airway hypersensitivity response have revealed critical roles of unfolded protein response (UPR) pathways in asthma. In this review, we highlight the roles of ER stress and UPR activation in the etiology, pathogenesis and treatment of asthma and discuss whether the related mechanisms could be targets for therapeutic strategies.

IL-33 in Chronic Respiratory Disease: From Preclinical to Clinical Studies

IL-33 has been deorphanized as a member of the IL-1 family and has key roles as an alarmin and cytokine with potent capacity to drive type 2 inflammation. This has led to a plethora of studies surrounding its role in chronic diseases with a type 2 inflammatory component. Here, we review the roles of IL-33 in two chronic respiratory diseases, asthma and chronic obstructive pulmonary disease (COPD). We discuss the hallmark and paradigm-shifting studies that have contributed to our understanding of IL-33 biology. We cover animal studies that have elucidated the mechanisms of IL-33 and assessed the role of anti-IL-33 treatment and immunization against IL-33. We highlight key clinical evidence for the potential of targeting increased IL-33 in respiratory diseases including exacerbations, and we outline current clinical trials using an anti-IL-33 monoclonal antibody in asthma patients. Finally, we discuss some of the challenges that have arisen in IL-33 biology and highlight potential future directions in targeting this cytokine in chronic respiratory diseases.

ATP/P2X7r axis mediates the pathological process of allergic asthma by inducing M2 polarization of alveolar macrophages

Recent studies revealed that macrophages are polarized towards the M2 phenotype in an ovalbumin (OVA)-induced asthmatic model. Alveolar macrophages (AMs) are immune barriers in alveoli to various pathogens in the respiratory tract; AMs suppress Th2 cell proliferation, inhibit interleukin (IL)-4, IL-5, and IL-13 secretion, and protect against airway hyperresponsiveness in allergic asthma. However, the polarization status and effects of different types of AMs in the pathogenesis of asthma are not known. ATP/P2X7r, expressed mainly on macrophages and dendritic cells, is associated with acute and chronic asthmatic airway inflammation and Th2 immune responses in mice and humans and functions by activating the NLRP3 inflammasome complex and inducing proinflammatory cytokine release (IL-1β and IL-18). Therefore, we evaluated the association between the ATP/P2X7r axis and different types of AMs in the pathology of allergic asthma. A murine AM-depleted asthma model was established by administration of clodronate-encapsulated liposomes, and M1-or M2-AMs were adoptively transferred to confirm the effects of different AMs in allergic asthma. Brilliant Blue G and BzATP were administered to OVA/HDM-induced mice in vivo. Lipopolysaccharide + OVA, ATP, Brilliant Blue G, and BzATP were used to stimulate AMs isolated from control and asthmatic mice. We found that selective depletion of AMs aggravated lung inflammation in asthmatic mice. Further, M2-type AMs may play a key role in mediating asthmatic inflammatory responses via the adoptive transfer of M2-type AMs to AM-depleted asthmatic mice, and the phenotype of AMs differentiated to M2 type in asthma. P2X7r expression in M2-type AMs was higher than that in M1-type AMs. Activating P2X7r induced polarization of M2-type AMs and inhibited polarization of M1-type AMs, while blockage of P2X7r had the opposite effect. The ATP/P2X7r axis may participate in the pathogenesis of asthma by mediating the M2-type AM polarization.

Cellular mechanisms underlying steroid-resistant asthma

Severe steroid-resistant asthma is clinically important, as patients with this form of the disease do not respond to mainstay corticosteroid therapies. The heterogeneity of this form of asthma and poor understanding of the pathological mechanisms involved hinder the identification of therapeutic targets and the development of more effective therapies. A major limiting factor in the understanding of severe steroid-resistant asthma is the existence of multiple endotypes represented by different immunological and inflammatory phenotypes, particularly in adults. Several clinical and experimental studies have revealed associations between specific respiratory infections and steroid-resistant asthma in adults. Here, we discuss recent findings from other authors as well as our own studies that have developed novel experimental models for interrogating the association between respiratory infections and severe steroid-resistant asthma. These models have enabled the identification of new therapies using macrolides, as well as several novel disease mechanisms, including the microRNA-21/phosphoinositide 3-kinase/histone deacetylase 2 axis and NLRP3 inflammasomes, and highlight the potential of these mechanisms as therapeutic targets.

Microbiome-focused asthma management strategies

Asthma is a common, heterogeneous and serious disease with high prevalence globally. Poorly controlled, steroid-resistant asthma is particularly important as there are no effective therapies and it exerts substantial healthcare and societal burden. The role of microbiomes, particularly in chronic diseases has generated considerable interest in recent times. Existing evidence clearly demonstrates an association between asthma initiation and the microbiome, both respiratory and gastro-intestinal, although its' roles are poorly understood when assessing the asthma progression or heterogeneity (i.e. phenotypes/endotypes) across different geographical locations. Moreover, modulating microbiomes could be preventive and/or therapeutic in patients with asthma warrants urgent attention. Here, we review recent advances in assessing the role of microbiomes in asthma and present the challenges associated with the potential therapeutic utility of modifying microbiomes in management.

Chitinase-like protein YKL-40 correlates with inflammatory phenotypes, anti-asthma responsiveness and future exacerbations

Background

Asthma is a heterogeneous chronic airway disease, which may be classified into different phenotypes. YKL-40 is a chitin-binding glycoprotein with unclear functions, but its expression is associated with inflammation and tissue remodeling. However, few studies have explored whether YKL-40 is associated with inflammatory phenotypes of asthma.

Methods

The study had two parts. Study I (n = 115) was a one-year prospective cohort designed to explore the relationship of serum YKL-40 levels with inflammatory phenotypes of asthma at baseline, and during exacerbations. Study II (n = 62) was a four-week prospective cohort designed to define whether serum YKL-40 levels could predict responses to a fixed anti-asthma regimen. YKL-40, IL-6 and CCL22 levels were detected using ELISA, and a sputum inflammatory panel (including IL-1β, IL-5, IL-8 and TNF-α) was assessed using Luminex-based MILLIPLEX assay.

Results

Study I: Serum YKL-40 levels in non-eosinophilic asthma (NEA) i.e. neutrophilic (47.77 [29.59, 74.97] ng/mL, n = 40) and paucigranulocytic (47.36 [28.81, 61.68] ng/mL, n = 31) were significantly elevated compared with eosinophilic asthma (31.05 [22.41, 51.10] ng/mL, n = 44) (P = 0.015). Serum YKL-40levels positively correlated with blood neutrophils, sputum IL-1β and plasma IL-6 but negatively correlated with serum IgE and blood eosinophils (all P ≤ 0.05). Baseline YKL-40 levels predicted moderate to severe exacerbations within a one-year period (aOR = 4.13, 95% CI = [1.08, 15.83]). Study II: Serum YKL-40 was an independent biomarker of negative responses to anti-asthma regimens (adjusted Odds Ratio [aOR] = 0.82, 95% CI = [0.71, 0.96].

Conclusions

These studies show that YKL-40 is a non-type 2 inflammatory signature for NEA, which could predict responsiveness or insensitivity to anti-asthma medications and more exacerbations. Further studies are needed to assess whether monitoring YKL-40 levels could provide potential implications for clinical relevance.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1051-9) contains supplementary material, which is available to authorized users.

Experimental protocol for development of adjuvant-free murine chronic model of allergic asthma

BACKGROUND

Mouse models of allergic asthma play a crucial role in exploring of asthma pathogenesis and testing of novel anti-inflammatory drugs. Widely used acute asthma models usually developed with adjuvant (aluminum hydroxide (alum)) do not reproduce one of the main asthma feature - airway remodeling while chronic asthma model mimic the pathophysiology of human disease. Moreover, the use of alum causes distress in experimental animals and impedes the test of adjuvant-containing drugs. In this study, we aimed to develop a chronic adjuvant-free asthma model with pronounced asthmatic phenotype.

METHODS

Female BALB/c mice were divided into 3 groups. The first group was sensitized with intraperitoneal injections of ovalbumin (OVA) emulsified in aluminum hydroxide on days 0, 14, 28 followed by two stages of intranasally challenge with OVA on days 41-43 and 62-64. The second group was subcutaneously sensitized with the same dose of OVA without adjuvant and challenged on the same days. The third group (negative control) included mice which did not received any kind of treatment (i.e. sensitization and challenge). Serum levels of OVA-specific IgE, IgG2a and IgG1 antibodies were detected by ELISA. Airway hyper-responsiveness was measured by non-invasive plethysmography on days 44 and 65. Bronchoalveolar lavage fluids (BALF) sampled in all groups on days 45 and 66 were analyzed by light microscopy. The left lung was removed for histological analysis. The IL-4 and IFNγ mRNA expression in BALF cells was evaluated by RT-PCR.

RESULTS

The OVA-specific IgE antibody response was two-fold increased in mice from adjuvant-free group compared to the adjuvant group that reflects reorientation of immune response towards Th2 phenotype. At the same time, the level of OVA-specific IgG1 and IgG2a antibodies was increased in the adjuvant group. Airway hyperresponsiveness to methacholine in mice of both experimental groups was two-fold higher than in control. Analysis of cell composition in BAL has shown a significant increase in eosinophil count in both experimental groups that indicate the development of allergic inflammation. Lung histology revealed airway remodeling in both experimental groups including goblet cell hyperplasia/metaplasia, thickening of airway walls, collagen deposition in the wall of distal airways. Additionally, the tendency to develop hypertrophy of bronchial smooth muscle layer was observed. Study of gene expression in BAL cells revealed the increase of IL-4 level in both adjuvant and adjuvant-free groups while IFNγ expression in both experimental groups was similar to control group.

CONCLUSION

We have developed a chronic adjuvant-free mouse asthma model which possesses all necessary features of the disease including airway remodeling and is more suitable for pre-clinical evaluation of novel therapeutic approaches including adjuvant-containing drugs.

Pulmonary group 2 innate lymphoid cells: surprises and challenges

Group 2 innate lymphoid cells (ILC2s) are a recently described subset of innate lymphocytes with important immune and homeostatic functions at multiple tissue sites, especially the lung. These cells expand locally after birth and during postnatal lung maturation and are present in the lung and other peripheral organs. They are modified by a variety of processes and mediate inflammatory responses to respiratory pathogens, inhaled allergens and noxious particles. Here, we review the emerging roles of ILC2s in pulmonary homeostasis and discuss recent and surprising advances in our understanding of how hormones, age, neurotransmitters, environmental challenges, and infection influence ILC2s. We also review how these responses may underpin the development, progression and severity of pulmonary inflammation and chronic lung diseases and highlight some of the remaining challenges for ILC2 biology.

The effect of L-theanine supplementation on the immune system of athletes exposed to strenuous physical exercise

Background

The aim of this study was to analyze the response of selected components of the immune system in rowers to maximal physical exercise, and to verify if this response could be modulated by supplementation with L-theanine.

Method

The double-blind study included 20 members of the Polish Rowing Team. The subjects were randomly assigned to the supplemented group (n = 10), receiving 150 mg of L-theanine extract for 6 weeks, or to the placebo group (n = 10). The participants performed a 2000-m test on a rowing ergometer at the beginning (1st examination) and at the end of the supplementation period (2nd examination). Blood samples were obtained from the antecubital vein before each exercise test, 1 min after completing the test, and after a 24-h recovery. Subpopulations of T regulatory lymphocytes (Tregs) (CD4+/CD25+/CD127-), cytotoxic lymphocytes (CTLs) (CD8+/TCRαβ+), natural killer (NK) cells (CD3-/CD16+/CD56+) and TCRδγ-positive (Tδγ) cells were determined by means of flow cytometry. The levels of interleukin 2 (IL-2), interleukin 4 (IL-4), interleukin 10 (IL-10), interferon gamma (INF-ɤ) and total antioxidant capacity (TAC) were determined with commercially available diagnostic kits.

Results

Supplementation with L-theanine contributed to a significant post-exercise decrease in IL-10 concentration, which was reflected by higher values of IL-2 to IL-10 and IFN-γ to IL-10 ratios. Moreover, a significant post-recovery decrease in CTL count, Treg to NK and Treg to CTL ratios was observed in the supplemented group.

Conclusion

Despite the decrease in the number of some cytotoxic cells (CTLs) and an increase in the proportion of Tregs to CTLs, supplementation with LTE seems to exert a beneficial effect on a disrupted Th1/Th2 balance in elite athletes, as shown by the decrease in IL-10 concentration.

Mucin 1 downregulation impairs the anti-necroptotic effects of glucocorticoids in human bronchial epithelial cells

AIMS

To investigate whether mucin 1 (MUC1) downregulation reduced the sensitivity of tumor necrosis factor-alpha (TNF-α)-induced bronchial epithelial cells to glucocorticoid-mediated necroptosis and explore the underlying mechanisms.

MAIN METHODS

The human lung bronchial epithelial cell line (16HBE) was transfected with small interfering RNA (siRNA) against MUC1 and then stimulated by TNF-α, where some cells were pretreated with dexamethasone. Flow cytometry was performed to analyze necroptosis in 16HBE cells, and western blot analysis was used to detect protein expression levels of MUC1, glucocorticoid receptor (GR)α, GRβ, NF-κB p65, phospho-p65 (p-p65), and histone deacetylase-2 (HDAC2). Additionally, nuclear translocation of MUC1 and GRα was assessed by immunofluorescence.

KEY FINDINGS

We observed that MUC1 downregulation by siRNA significantly augmented TNF-α-induced necroptosis in 16HBE cells, and that dexamethasone showed impaired anti-necroptotic effects of MUC1 downregulation. Furthermore, we found that GRα nuclear translocation was inhibited in 16HBE cells with MUC1 downregulation, and that dexamethasone-mediated inhibition of p65 phosphorylation was lower in cells transfected with MUC1-siRNA compared to those transfected with negative control siRNA.

SIGNIFICANCE

Impaired GRα nuclear translocation and inhibited p-p65 expression might contribute to glucocorticoid resistance caused by MUC1 deficiency in TNF-α-induced necroptosis in 16HBE cells, and should be considered as a potential target for the development of novel therapeutics for asthma.

Evaluation of the protective and therapeutic effects of Pistacia atlantica gum aqueous extract on cellular and pathological aspects of experimental asthma in Balb/c mice

OBJECTIVE

The purpose of this study was to investigate the protective and therapeutic effects of aqueous extract of P. atlantica gum on an experimental asthma in BALB/c mice.

MATERIALS AND METHODS

Aqueous extract of dried and milled P. atlantica gum was assemble and evaluate by GC-MS. In order to investigate the effect of P. atlantica gum extract on cellular and pathological aspects of asthma, 60 BALB/c mice were divided into six groups as: negative control, asthmatic group, asthmatic group receiving dexamethasone (1mg/kg; intraperitoneal (IP)) and three asthmatic groups receiving different concentrations of the extract (100, 200 and 400 mg/kg, orally) from the beginning of the study and continued for 84 days. The examined parameters included cell population, IgE antibody production, levels of IL-4, IL-5, TGF-β, INF-γ, IL-10, and IL-17 cytokines, and lung tissue damage.

RESULTS

Regardless of the dose, aqueous extract of P. atlantica gum, caused significant decrease in the number of BALF eosinophilic cells and levels of anti-ovalbumin IgE, IL-4, IL-5 and IL-17 cytokine levels, as well as pathologic damage of the lung tissue. In addition, the amount of anti-inflammatory IL-10, TGF-β, and INF-γ Th1 cytokines significantly increased in the extract-treated groups compared to the asthmatic and dexamethasone-treated groups. Moreover, IFN-γ/IL-4 ratio significantly increased in a dose-dependent manner compared to the un-treated asthma group.

CONCLUSION

The aqueous extract of P. atlantica gum can be considered as a potent anti-inflammatory and immunomodulatory compound and may be used as a natural compound for treatment of immune system disorders.

Hydroxysafflor Yellow A Suppresses Platelet Activating Factor-Induced Activation of Human Small Airway Epithelial Cells

Hydroxysafflor yellow A (HSYA) is a chemical component isolated from the Chinese medicine Carthamus tinctorius L. HSYA has numerous pharmacological effects, including protecting against and mitigating some respiratory diseases such as acute lung injury and chronic obstructive pulmonary disease; however, its effect on asthma remains unclear. We previously found that HSYA attenuated ovalbumin-induced allergic asthma in guinea pigs. Platelet activating factor (PAF) is a phospholipid mediator of inflammation and an important factor in the pathological process of asthma. In this study, we investigated the anti-inflammatory effects of HSYA and its underlying mechanisms in PAF-induced human small airway epithelial cells (HSAECs). PAF-activated cells were pretreated with HSYA and/or the PAF receptor inhibitor, ginkgolide B, and we observed changes in the expression of interleukin (IL)-1β, IL-6, and tumor necrosis factor alpha, monolayer permeability of HSAECs, and inflammatory signaling pathways. HSYA attenuated the PAF-induced increase in expression of inflammatory factors and destruction of cell-barrier function, and inhibited the expression of protein kinase C, mitogen-activated protein kinases, activator protein-1, and nuclear factor-κB activation induced by PAF. These findings suggest that HSYA may represent a potential new drug for the treatment of asthma.

Critical role of inflammatory mast cell in fibrosis: Potential therapeutic effect of IL-37

BACKGROUND

Fibrosis involves the activation of inflammatory cells, leading to a decrease in physiological function of the affected organ or tissue.

AIMS

To update and synthesize relevant information concerning fibrosis into a new hypothesis to explain the pathogenesis of fibrosis and propose potential novel therapeutic approaches.

MATERIALS AND METHODS

Literature was reviewed and relevant information is discussed in the context of the pathogenesis of fibrosis.

RESULTS

A number of cytokines and their mRNA are involved in the circulatory system and in organs of patients with fibrotic tissues. The profibrotic cytokines are generated by several activated immune cells, including fibroblasts and mast cells (MCs), which are important for tissue inflammatory responses to different types of injury. MC-derived TNF, IL-1, and IL-33 contribute crucially to the initiation of a cascade of the host defence mechanism(s), leading to the fibrosis process. Inhibition of TNF and inflammatory cytokines may slow the progression of fibrosis and improve the pathological status of the affected subject. IL-37 is generated by various types of immune cells and is an IL-1 family member protein. IL-37 is not a receptor antagonist; it binds IL-18 receptor alpha (IL-18Rα) and delivers the inhibitory signal by using TIR8. It has been shown that IL-37 can be protective in inflammation and injury, and inhibits both innate and adaptive immunity.

DISCUSSION

IL-37 may be useful for suppression of inflammatory diseases induced by inhibiting MyD88-dependent TLR signalling. In addition, IL-37 downregulates NF-κB induced by TLR2 or TLR4 through a mechanism dependent on IL-18Rα.

CONCLUSION

This review summarizes current knowledge on the role of MC in inflammation and tissue/organ fibrosis, with a focus on the therapeutic potential of IL-37-targeting cytokines.

RelB-Deficient Dendritic Cells Promote the Development of Spontaneous Allergic Airway Inflammation

RelB is a member of the NF-κB family, which is essential for dendritic cell (DC) function and maturation. However, the contribution of RelB to the development of allergic airway inflammation (AAI) is unknown. Here, we identify a pivotal role for RelB in the development of spontaneous AAI that is independent of exogenous allergen exposure. We assessed AAI in two strains of RelB-deficient (RelB^-/-) mice: one with a targeted deletion and one expressing a major histocompatibility complex transgene. To determine the importance of RelB in DCs, RelB-sufficient DCs (RelB^+/+ or RelB^-/-) were adoptively transferred into RelB^-/- mice. Both strains had increased pulmonary inflammation compared with their respective wild-type (RelB^+/+) and heterozygous (RelB^+/-) controls. RelB^-/- mice also had increased inflammatory cell influx into the airways, levels of chemokines (CCL2/3/4/5/11/17 and CXCL9/10/13) and T-helper cell type 2-associated cytokines (IL-4/5) in lung tissues, serum IgE, and airway remodeling (mucus-secreting cell numbers, collagen deposition, and epithelial thickening). Transfer of RelB^+/- CD11c⁺ DCs into RelB^-/- mice decreased pulmonary inflammation, with reductions in lung chemokines, T-helper cell type 2-associated cytokines (IL-4/5/13/25/33 and thymic stromal lymphopoietin), serum IgE, type 2 innate lymphoid cells, myeloid DCs, γδ T cells, lung Vβ13⁺ T cells, mucus-secreting cells, airway collagen deposition, and epithelial thickening. These data indicate that RelB deficiency may be a key pathway underlying AAI, and that DC-encoded RelB is sufficient to restore control of this inflammation.

A bispecific antibody strategy to target multiple type 2 cytokines in asthma

BACKGROUND

Asthma is a chronic inflammatory airway disease in which innate and adaptive immune cells act together to cause eosinophilic inflammation, goblet cell metaplasia (GCM), and bronchial hyperreactivity (BHR). In clinical trials using biologicals against IL-4 receptor (IL-4R) α or IL-5, only a subset of patients with moderate-to-severe asthma responded favorably, suggesting that distinct pathophysiologic mechanisms are at play in subgroups of patients called endotypes. However, the effect of multiple cytokine blockade using bispecific antibodies has not been tested.

OBJECTIVE

We sought to target simultaneously the IL-4, IL-13, and IL-5 signaling pathways with a novel IL-4Rα/IL-5-bispecific antibody in a murine house dust mite (HDM) model of asthma.

METHODS

Two mAbs neutralizing IL-4Rα and IL-5 were generated by using a llama-based antibody platform. Their heavy and light chains were then cotransfected in mammalian cells, resulting in a heterogeneous antibody mixture from which the bispecific antibody was isolated by using a dual anti-idiotypic purification process. C57BL/6J mice were finally sensitized and challenged to HDM extracts and treated during challenge with the antibodies.

RESULTS

We successfully generated and characterized the monospecific and bispecific antibodies targeting IL-4Rα and IL-5. The monospecific antibodies could suppress eosinophilia, IgE synthesis, or both, whereas only the IL-4Rα/IL-5-bispecific antibody and the combination of monospecific antibodies additionally inhibited GCM and BHR.

CONCLUSION

Type 2 cytokines act synergistically to cause GCM and BHR in HDM-exposed mice. These preclinical results show the feasibility of generating bispecific antibodies that target multiple cytokine signaling pathways as superior inhibitors of asthma features, including the difficult-to-treat GCM.

Genetic Mechanisms of Asthma and the Implications for Drug Repositioning

Asthma is a chronic disease that is caused by airway inflammation. The main features of asthma are airway hyperresponsiveness (AHR) and reversible airway obstruction. The disease is mainly managed using drug therapy. The current asthma drug treatments are divided into two categories, namely, anti-inflammatory drugs and bronchodilators. However, disease control in asthma patients is not very efficient because the pathogenesis of asthma is complicated, inducing factors that are varied, such as the differences between individual patients. In this paper, we delineate the genetic mechanisms of asthma, and present asthma-susceptible genes and genetic pharmacology in an attempt to find a diagnosis, early prevention, and treatment methods for asthma. Finally, we reposition some clinical drugs for asthma therapy, based on asthma genetics.

Mechanisms and treatments for severe, steroid-resistant allergic airway disease and asthma

Severe, steroid-resistant asthma is clinically and economically important since affected individuals do not respond to mainstay corticosteroid treatments for asthma. Patients with this disease experience more frequent exacerbations of asthma, are more likely to be hospitalized, and have a poorer quality of life. Effective therapies are urgently required, however, their development has been hampered by a lack of understanding of the pathological processes that underpin disease. A major obstacle to understanding the processes that drive severe, steroid-resistant asthma is that the several endotypes of the disease have been described that are characterized by different inflammatory and immunological phenotypes. This heterogeneity makes pinpointing processes that drive disease difficult in humans. Clinical studies strongly associate specific respiratory infections with severe, steroid-resistant asthma. In this review, we discuss key findings from our studies where we describe the development of representative experimental models to improve our understanding of the links between infection and severe, steroid-resistant forms of this disease. We also discuss their use in elucidating the mechanisms, and their potential for developing effective therapeutic strategies, for severe, steroid-resistant asthma. Finally, we highlight how the immune mechanisms and therapeutic targets we have identified may be applicable to obesity-or pollution-associated asthma.

Dietary omega-6, but not omega-3, polyunsaturated or saturated fatty acids increase inflammation in primary lung mesenchymal cells

Obesity is an important risk factor for developing severe asthma. Dietary fatty acids, which are increased in sera of obese individuals and after high-fat meals, activate the innate immune system and induce inflammation. This study investigated whether dietary fatty acids directly cause inflammation and/or synergize with obesity-induced cytokines in primary human pulmonary fibroblasts in vitro. Fibroblasts were challenged with BSA-conjugated fatty acids [ω-6 polyunsaturated fatty acids (PUFAs) and ω-3 PUFAs or saturated fatty acids (SFAs)], with or without TNF-α, and release of the proinflammatory cytokines, IL-6 and CXCL8, was measured. We found that the ω-6 PUFA arachidonic acid (AA), but not ω-3 PUFAs or SFAs, upregulates IL-6 and CXCL8 release. Combined AA and TNF-α challenge resulted in substantially greater cytokine release than either alone, demonstrating synergy. Synergistic upregulation of IL-6, but not CXCL8, was mainly mediated via cyclooxygenase (COX). Inhibition of p38 MAPK reduced CXCL8 release, induced by AA and TNF-α alone, but not in combination. Synergistic CXCL8 release, following AA and TNF-α challenge, was not medicated via a single signaling pathway (MEK1, JNK, phosphoinositide 3-kinase, and NF-κB) nor by hyperactivation of NF-κB or p38. To investigate if these findings occur in other airway cells, effects of AA in primary human airway smooth muscle (ASM) cells and human bronchial epithelial cells were also investigated. We found proinflammatory effects in ASM cells but not epithelial cells. This study suggests that diets rich in ω-6 PUFAs might promote airway inflammation via multiple pathways, including COX-dependent and -independent pathways, and in an obese person, may lead to more severe airway inflammation.

Persistent induction of goblet cell differentiation in the airways: Therapeutic approaches

Dysregulated induction of goblet cell differentiation results in excessive production and retention of mucus and is a common feature of several chronic airways diseases. To date, therapeutic strategies to reduce mucus accumulation have focused primarily on altering the properties of the mucus itself, or have aimed to limit the production of mucus-stimulating cytokines. Here we review the current knowledge of key molecular pathways that are dysregulated during persistent goblet cell differentiation and highlights both pre-existing and novel therapeutic strategies to combat this pathology.

Biomarkers for severe eosinophilic asthma

The last decade has seen the approval of several new biologics for the treatment of severe asthma-targeting specific endotypes and phenotypes. This review will examine how evidence generated from the mepolizumab clinical development program showed that blood eosinophil counts, rather than sputum or tissue eosinophil counts, evolved as a pharmacodynamic and predictive biomarker for the efficacy of treatment with mepolizumab in patients with severe eosinophilic asthma. Based on the available evidence and combined with clinical judgement, a baseline blood eosinophil threshold of 150 cells/μL or greater or a historical blood eosinophil threshold of 300 cells/μL or greater will allow selection of patients with severe eosinophilic asthma who are most likely to achieve clinically significant reductions in the rate of exacerbations with mepolizumab treatment.