Pathogenesis of Asthma

The causality between C-reactive protein and asthma: a two-sample Mendelian randomization analysis

PURPOSE

This study sought to investigate the causal effects of circulating C-reactive protein (CRP) level on risk of asthma and its subtypes by two-sample Mendelian randomization (MR) analysis.

METHODS

We utilized single nucleotide polymorphisms (SNPs) associated with both CRP and outcomes of asthma, allergic asthma, and obesity-related asthma as genetic variables via a genome-wide summary association study (GWAS). MR analysis mainly based on the inverse variance weighted (IVW) method was performed to infer the causal relationship between exposure and outcomes. Cochran's Q test and MR-Egger regression analysis were performed to determine respectively the heterogeneity and pleiotropy among instrumental variables (IVs), and leave-one-out analysis was conducted to determine the stability of the MR results.

RESULTS

In our study, 42 SNPs were identified as IVs for MR analyses. According to the primary inference results by IVW methods, circulating CRP was demonstrated to be significantly associated with risk of asthma [odds ratio (OR): 1.046; 95% confidence interval (95% CI): 1.004-1.090; P = .030] and obesity-related asthma (OR: 1.072; 95% CI: 1.009-1.138; P = 0.025), whereas no distinct causality with allergic asthma was found (OR: 1.051; 95% CI: 0.994-1.112; P = .081). Sensitivity analyses indicated that there was no horizontal pleiotropy among IVs, and the MR results were proved to be robust by leave-one-out sensitivity analysis, despite the presence of heterogeneity.

CONCLUSION

The present study suggested that higher CRP might genetically predict an increased risk of developing asthma and obesity-related asthma, without causality with allergic asthma.

The effects of inhaled corticosteroids on healthy airways

BACKGROUND

The effects of inhaled corticosteroids (ICS) on healthy airways are poorly defined.

OBJECTIVES

To delineate the effects of ICS on gene expression in healthy airways, without confounding caused by changes in disease-related genes and disease-related alterations in ICS responsiveness.

METHODS

Randomized open-label bronchoscopy study of high-dose ICS therapy in 30 healthy adult volunteers randomized 2:1 to (i) fluticasone propionate 500 mcg bd daily or (ii) no treatment, for 4 weeks. Laboratory staff were blinded to allocation. Biopsies and brushings were analysed by immunohistochemistry, bulk RNA sequencing, DNA methylation array and metagenomics.

RESULTS

ICS induced small between-group differences in blood and lamina propria eosinophil numbers, but not in other immunopathological features, blood neutrophils, FeNO, FEV1, microbiome or DNA methylation. ICS treatment upregulated 72 genes in brushings and 53 genes in biopsies, and downregulated 82 genes in brushings and 416 genes in biopsies. The most downregulated genes in both tissues were canonical markers of type-2 inflammation (FCER1A, CPA3, IL33, CLEC10A, SERPINB10 and CCR5), T cell-mediated adaptive immunity (TARP, TRBC1, TRBC2, PTPN22, TRAC, CD2, CD8A, HLA-DQB2, CD96, PTPN7), B-cell immunity (CD20, immunoglobulin heavy and light chains) and innate immunity, including CD48, Hobit, RANTES, Langerin and GFI1. An IL-17-dependent gene signature was not upregulated by ICS.

CONCLUSIONS

In healthy airways, 4-week ICS exposure reduces gene expression related to both innate and adaptive immunity, and reduces markers of type-2 inflammation. This implies that homeostasis in health involves tonic type-2 signalling in the airway mucosa, which is exquisitely sensitive to ICS.

House dust mite allergen avoidance strategies for the treatment of allergic asthma: A hypothesis-generating meta-analysis

Background

This study continues the review by Gøtzsche and Johansen (Cochrane Database of Systematic Reviews, 2008, Art. No: CD001187), aiming to systematically generate hypotheses on the effectiveness of (sub)strategies for house dust mite allergen avoidance in the treatment of allergic asthma.

Methods

We used the trials previously analysed by Gøtzsche and Johansen and searched recently published studies. Data on asthma symptom scores (ASS), ACQ, number of improved patients, AQLQ-scores, medication use, FEV1%, PC20, and FeNO levels were analysed. The effectiveness of strategies was assessed using Metafor in R.

Results

Thirty-five trials involving 2419 patients were included in the final study. The patient-reported outcome number of patients with improved condition following total bedroom control was RR = 3.39 (95% confidence interval: 1.04 to 11.04, P = 0.04). The mean differences in the ASS by nocturnal air purification was -0.7 (95% confidence interval: -1.08 to -0.32, P < 0.001). Other outcomes including partial bedroom control were non-significant or clinically not of importance.

Conclusions

Total bedroom control and nocturnal air purification of the breathing zone hypothetically provides clinical benefits in patients with house dust mite-induced allergic asthma. The number of patients with improvements in their condition respectively the asthma symptom score differences showed potential in small subgroups, consisting of single studies. Partial bedroom control is not recommended.

Systematic Review Registration

Prospero CRD42022323660.

MicroRNA-mediated Krüppel-like factor 4 upregulation induces alternatively activated macrophage-associated marker and chemokine transcription in 4,4'-methylene diphenyl diisocyanate exposed macrophages

1. Occupational exposure to 4,4'-methylene diphenyl diisocyanate (MDI) is associated with occupational asthma (OA) development. Alveolar macrophage-induced recruitment of immune cells to the lung microenvironment plays an important role during asthma pathogenesis. Previous studies identified that MDI/MDI-glutathione (GSH)-exposure downregulates endogenous hsa-miR-206-3p/hsa-miR-381-3p. Our prior report shows that alternatively activated (M2) macrophage-associated markers/chemokines are induced by MDI/MDI-GSH-mediated Krüppel-Like Factor 4 (KLF4) upregulation in macrophages and stimulates immune cell chemotaxis. However, the underlying molecular mechanism(s) by which MDI/MDI-GSH upregulates KLF4 remain unclear.

2. Following MDI-GSH exposure, microRNA(miR)-inhibitors/mimics or plasmid transfection, endogenous hsa-miR-206-3p/hsa-miR-381-3p, KLF4, or M2 macrophage-associated markers (CD206, TGM2), and chemokines (CCL17, CCL22, CCL24) were measured by either RT-qPCR, western blot, or luciferase assay.

3. MDI-GSH exposure downregulates hsa-miR-206-3p/hsa-miR-381-3p by 1.46- to 9.75-fold whereas upregulates KLF4 by 1.68- to 1.99-fold, respectively. In silico analysis predicts binding between hsa-miR-206-3p/hsa-miR-381-3p and KLF4. Gain- and loss-of-function, luciferase reporter assays and RNA-induced silencing complex-immunoprecipitation (RISC-IP) studies confirm the posttranscriptional regulatory roles of hsa-miR-206-3p/hsa-miR-381-3p and KLF4 in macrophages. Furthermore, hsa-miR-206-3p/hsa-miR-381-3p regulate the expression of M2 macrophage-associated markers and chemokines via KLF4.

4. In conclusion, hsa-miR-206-3p/hsa-miR-381-3p play a major role in regulation of MDI/MDI-GSH-induced M2 macrophage-associated markers and chemokines by targeting the KLF4 transcript, and KLF4-mediated regulation in macrophages.

Natural killer T cells in allergic asthma: implications for the development of novel immunotherapeutical strategies

Allergic asthma has emerged as a prevalent allergic disease worldwide, affecting most prominently both young individuals and lower-income populations in developing and developed countries. To devise effective and curative immunotherapy, it is crucial to comprehend the intricate nature of this condition, characterized by an immune response imbalance that favors a proinflammatory profile orchestrated by diverse subsets of immune cells. Although the involvement of Natural Killer T (NKT) cells in asthma pathology is frequently implied, their specific contributions to disease onset and progression remain incompletely understood. Given their remarkable ability to modulate the immune response through the rapid secretion of various cytokines, NKT cells represent a promising target for the development of effective immunotherapy against allergic asthma. This review provides a comprehensive summary of the current understanding of NKT cells in the context of allergic asthma, along with novel therapeutic approaches that leverage the functional response of these cells.

The contribution of the WNT pathway to the therapeutic effects of montelukast in experimental murine airway inflammation induced by ovalbumin and lipopolysaccharide

The wingless/integrase-1 (WNT) pathway involved in the pathogenesis of inflammatory airway diseases has recently generated considerable research interest. Montelukast, a leukotriene receptor antagonist, provides therapeutic benefits in allergic asthma involving eosinophils. We aimed to investigate the role of the WNT pathway in the therapeutic actions of montelukast (MT) in a mixed type of allergic-acute airway inflammation model induced by ovalbumin (OVA) and lipopolysaccharide (LPS) in mice. Female mice were sensitized with intraperitoneal OVA-Al(OH)3 administration in the initiation phase and intranasal OVA followed by LPS administration in the challenge phase. The mice were divided into eight groups: control, asthmatic, and control/asthmatic treated with XAV939 (inhibitor of the canonical WNT pathway), LGK-974 (inhibitor of the secretion of WNT ligands), or MT at different doses. The inhibition of the WNT pathway prevented tracheal 5-HT and bradykinin hyperreactivity, while only the inhibition of the canonical WNT pathway partially reduced 5-HT and bradykinin contractions compared to the inflammation group. Therefore, MT treatment hindered 5-HT and bradykinin hyperreactivity associated with airway inflammation. Furthermore, MT prevented the increases in the phosphorylated GSK-3β and WNT5A levels, which had been induced by airway inflammation, in a dose-dependent manner. Conversely, the MT application caused a further increase in the fibronectin levels, while there was no significant alteration in the phosphorylation of the Smad-2 levels in the isolated lungs of the mice. The MT treatment reversed the increase in the mRNA expression levels of interleukin-17A. An increase in eosinophil and neutrophil counts was observed in bronchoalveolar lavage fluid samples obtained from the mice in the inflammation group, which was hampered by the MT treatment. The inhibition of the WNT pathway did not alter inflammatory cytokine expression or cell infiltration. The WNT pathway mediated the therapeutic effects of MT due to the inhibition of GSK-3β phosphorylation as well as the reduction of WNT5A levels in a murine airway inflammation model.

Airway remodelling in asthma and the epithelium: on the edge of a new era

Asthma is a chronic, heterogeneous disease of the airways, often characterised by structural changes known collectively as airway remodelling. In response to environmental insults, including pathogens, allergens and pollutants, the epithelium can initiate remodelling via an inflammatory cascade involving a variety of mediators that have downstream effects on both structural and immune cells. These mediators include the epithelial cytokines thymic stromal lymphopoietin, interleukin (IL)-33 and IL-25, which facilitate airway remodelling through cross-talk between epithelial cells and fibroblasts, and between mast cells and airway smooth muscle cells, as well as through signalling with immune cells such as macrophages. The epithelium can also initiate airway remodelling independently of inflammation in response to the mechanical stress present during bronchoconstriction. Furthermore, genetic and epigenetic alterations to epithelial components are believed to influence remodelling. Here, we review recent advances in our understanding of the roles of the epithelium and epithelial cytokines in driving airway remodelling, facilitated by developments in genetic sequencing and imaging techniques. We also explore how new and existing therapeutics that target the epithelium and epithelial cytokines could modify airway remodelling.

Therapeutic potential of mesenchymal stem cell-derived exosomes for allergic airway inflammation

Due to their immunomodulatory capacities, mesenchymal stem cells (MSCs) have been extensively used as therapeutic approaches in cell-based therapy for various inflammatory diseases. Several lines of studies have shown that the most beneficial effects of MSCs are associated with MSC-derived exosomes. Exosomes are nanoscale extracellular vesicles that contain important biomolecules such as RNA, microRNAs (miRNAs), DNA, growth factors, enzymes, chemokines, and cytokines that regulate immune cell functions and parenchymal cell survival. Recently, exosomes, especially MSC-derived exosomes, have been shown to have protective effects in allergic airway inflammation. This review focused on the immune-regulatory potential of MSC-derived exosomes as nanoscale delivery systems in the treatment of allergic airway inflammation.

Computer-aided investigation of Traditional Chinese Medicine mechanisms: A case study of San-Ao decoction in asthma treatment

The San-Ao Decoction (SAD) is a well-known Traditional Chinese Medicine (TCM) formula used to alleviate respiratory symptoms, including asthma. However, its precise mechanisms of action have remained largely unknown. In this study, we utilized computer-aided approaches to explore these mechanisms. Firstly, we conducted a comprehensive analysis of the chemical composition of SAD, which allowed us to identify the 28 main ingredients. Then, we employed computer simulations to investigate the potential active ingredients of SAD and the corresponding binding sites of transient receptor potential vanilloid 1 (TRPV1). The simulations revealed that D509 and D647 were the potential binding sites for TRPV1. Notably, molecular dynamics (MD) studies indicated that site D509 may function as an allosteric site of TRPV1. Furthermore, to validate the computer-aided predictions, we performed experimental studies, including in vitro and in vivo assays. The results of these experiments confirmed the predictions made by our computational models, providing further evidence for the mechanisms of action of San-Ao Decoction in asthma treatment. Our findings demonstrated that: i) D509 and D647 of TRPV1 are the key binding sites for the main ingredients of SAD; ii) SAD or its main ingredients significantly reduce the influx of Ca2+ through TRPV1, following the TCM principle of "Jun, Chen, Zuo, Shi"; iii) SAD shows efficiency in comprehensive in vivo validation. In conclusion, our computer-aided investigation of San-Ao Decoction in asthma treatment has provided valuable insights into the therapeutic mechanisms of this TCM formula. The combination of computational analysis and experimental validation has proven effective in enhancing our understanding of TCM and may pave the way for future discoveries in the field.

Critical Care Management of Severe Asthma Exacerbations

Severe asthma exacerbations, including near-fatal asthma (NFA), have high morbidity and mortality. Mechanical ventilation of patients with severe asthma is difficult due to the complex pathophysiology resulting from severe bronchospasm and dynamic hyperinflation. Life-threatening complications of traditional ventilation strategies in asthma exacerbations include the development of systemic hypotension from hyperinflation, air trapping, and pneumothoraces. Optimizing pharmacologic techniques and ventilation strategies is crucial to treat the underlying bronchospasm. Despite optimal pharmacologic management and mechanical ventilation, the mortality rate of patients with severe asthma in intensive care units is 8%, suggesting a need for advanced non-pharmacologic therapies, including extracorporeal life support (ECLS). This review focuses on the pathophysiology of acute asthma exacerbations, ventilation management including non-invasive ventilation (NIV) and invasive mechanical ventilation (IMV), the pharmacologic management of acute asthma, and ECLS. This review also explores additional advanced non-pharmacologic techniques and monitoring tools for the safe and effective management of critically ill adult asthmatic patients.

Functional role of glial-derived neurotrophic factor in a mixed allergen murine model of asthma

Our previous study showed that glial-derived neurotrophic factor (GDNF) expression is upregulated in asthmatic human lungs, and GDNF regulates calcium responses through its receptor GDNF family receptor α1 (GFRα1) and RET receptor in human airway smooth muscle (ASM) cells. In this study, we tested the hypothesis that airway GDNF contributes to airway hyperreactivity (AHR) and remodeling using a mixed allergen mouse model. Adult C57BL/6J mice were intranasally exposed to mixed allergens (ovalbumin, Aspergillus, Alternaria, house dust mite) over 4 wk with concurrent exposure to recombinant GDNF, or extracellular GDNF chelator GFRα1-Fc. Airway resistance and compliance to methacholine were assessed using FlexiVent. Lung expression of GDNF, GFRα1, RET, collagen, and fibronectin was examined by RT-PCR and histology staining. Allergen exposure increased GDNF expression in bronchial airways including ASM and epithelium. Laser capture microdissection of the ASM layer showed increased mRNA for GDNF, GFRα1, and RET in allergen-treated mice. Allergen exposure increased protein expression of GDNF and RET, but not GFRα1, in ASM. Intranasal administration of GDNF enhanced baseline responses to methacholine but did not consistently potentiate allergen effects. GDNF also induced airway thickening, and collagen deposition in bronchial airways. Chelation of GDNF by GFRα1-Fc attenuated allergen-induced AHR and particularly remodeling. These data suggest that locally produced GDNF, potentially derived from epithelium and/or ASM, contributes to AHR and remodeling relevant to asthma.NEW & NOTEWORTHY Local production of growth factors within the airway with autocrine/paracrine effects can promote features of asthma. Here, we show that glial-derived neurotrophic factor (GDNF) is a procontractile and proremodeling factor that contributes to allergen-induced airway hyperreactivity and tissue remodeling in a mouse model of asthma. Blocking GDNF signaling attenuates allergen-induced airway hyperreactivity and remodeling, suggesting a novel approach to alleviating structural and functional changes in the asthmatic airway.

Glucocorticoids, their uses, sexual dimorphisms, and diseases: new concepts, mechanisms, and discoveries

The normal stress response in humans is governed by the hypothalamic-pituitary-adrenal (HPA) axis through heightened mechanisms during stress, raising blood levels of the glucocorticoid hormone cortisol. Glucocorticoids are quintessential compounds that balance the proper functioning of numerous systems in the mammalian body. They are also generated synthetically and are the preeminent therapy for inflammatory diseases. They act by binding to the nuclear receptor transcription factor glucocorticoid receptor (GR), which has two main isoforms (GRα and GRβ). Our classical understanding of glucocorticoid signaling is from the GRα isoform, which binds the hormone, whereas GRβ has no known ligands. With glucocorticoids being involved in many physiological and cellular processes, even small disruptions in their release via the HPA axis, or changes in GR isoform expression, can have dire ramifications on health. Long-term chronic glucocorticoid therapy can lead to a glucocorticoid-resistant state, and we deliberate how this impacts disease treatment. Chronic glucocorticoid treatment can lead to noticeable side effects such as weight gain, adiposity, diabetes, and others that we discuss in detail. There are sexually dimorphic responses to glucocorticoids, and women tend to have a more hyperresponsive HPA axis than men. This review summarizes our understanding of glucocorticoids and critically analyzes the GR isoforms and their beneficial and deleterious mechanisms and the sexual differences that cause a dichotomy in responses. We also discuss the future of glucocorticoid therapy and propose a new concept of dual GR isoform agonist and postulate why activating both isoforms may prevent glucocorticoid resistance.

A Survey on Artificial Intelligence in Pulmonary Imaging

Over the last decade, deep learning (DL) has contributed a paradigm shift in computer vision and image recognition creating widespread opportunities of using artificial intelligence in research as well as industrial applications. DL has been extensively studied in medical imaging applications, including those related to pulmonary diseases. Chronic obstructive pulmonary disease, asthma, lung cancer, pneumonia, and, more recently, COVID-19 are common lung diseases affecting nearly 7.4% of world population. Pulmonary imaging has been widely investigated toward improving our understanding of disease etiologies and early diagnosis and assessment of disease progression and clinical outcomes. DL has been broadly applied to solve various pulmonary image processing challenges including classification, recognition, registration, and segmentation. This paper presents a survey of pulmonary diseases, roles of imaging in translational and clinical pulmonary research, and applications of different DL architectures and methods in pulmonary imaging with emphasis on DL-based segmentation of major pulmonary anatomies such as lung volumes, lung lobes, pulmonary vessels, and airways as well as thoracic musculoskeletal anatomies related to pulmonary diseases.

Prolonged inflammatory resolution in allergic asthma relates to dysfunctional interactions between neutrophils and airway epithelium

BACKGROUND

Allergic asthma is a heterogeneous disorder involving chronic airway inflammation, reversible airflow limitation, and tissue remodeling, causing chronic airflow limitation. Most of the asthma research has been focused on elucidating the proinflammatory pathways underlying disease pathogenesis. Paradoxically, the necessity of appropriate termination and resolution of inflammation has not been recognized until recently. The latter has led to the concept of chronic inflammation developing as a result of lack of specific "stop" signals for the inflammatory process.

OBJECTIVE

To investigate the interaction between neutrophils and airway epithelium during inflammatory resolution in patients with allergic asthma.

METHODS

An in vitro scratch assay with cultured epithelial cells, based on live-imaging microscopy, was used to evaluate regeneration and the influence of neutrophils on resolution. Epithelial cells and autologous neutrophils were derived from healthy donors and patients with allergic asthma. Supernatants and cells were collected for enzyme-linked immunosorbent assay and transcriptional analyses at the end of the experiment.

RESULTS

Healthy epithelial cells regenerated faster than epithelial cells from patients with allergic asthma. Autologous neutrophils improved the regeneration of healthy epithelial cells but not asthmatic epithelial cells. Interleukin (IL)-8 and β-catenin were down-regulated in healthy epithelial cells after resolution, but not in allergic asthmatic epithelial cells.

CONCLUSION

The prolonged duration of inflammation in the respiratory tract in patients with allergic asthma could be due to the impaired healing pattern of epithelial cells and their compromised interactions with the neutrophils.

Drug Development from Natural Products Based on the Pathogenic Mechanism of Asthma

Asthma is a chronic inflammatory disease of the pulmonary system associated with many wheeze-to-sleep apnea complications that may lead to death. In 2019, approximately 262 million patients suffered from asthma, and 455 thousand died from the disease worldwide. It is a more severe health problem in children and older adults, and as the aging of society intensifies, the problem will continue to worsen. Asthma inducers can be classified as indoor and outdoor allergens and can cause asthma due to their repeated invasion. There are several theories about asthma occurrence, such as the imbalance between Th1 and Th2, inflammation in the pulmonary system, and the abnormal apoptosis/cell proliferation of cells related to asthma. Although there are many medications for asthma, as it is an incurable disease, the purpose of the drugs is only to suppress the symptoms. The current drugs can be divided into relievers and controllers; however, as they have many adverse effects, such as immune suppression, growth retardation, promotion of cataracts, hyperactivity, and convulsions, developing new asthma drugs is necessary. Although natural products can have adverse effects, the development of asthma drugs from natural products may be beneficial, as some have anti-asthmatic effects such as immune modulation, anti-inflammation, and/or apoptosis modulation.

Epithelial-Mesenchymal Transition Mechanisms in Chronic Airway Diseases: A Common Process to Target?

Epithelial-to-mesenchymal transition (EMT) is a reversible process, in which epithelial cells lose their epithelial traits and acquire a mesenchymal phenotype. This transformation has been described in different lung diseases, such as lung cancer, interstitial lung diseases, asthma, chronic obstructive pulmonary disease and other muco-obstructive lung diseases, such as cystic fibrosis and non-cystic fibrosis bronchiectasis. The exaggerated chronic inflammation typical of these pulmonary diseases can induce molecular reprogramming with subsequent self-sustaining aberrant and excessive profibrotic tissue repair. Over time this process leads to structural changes with progressive organ dysfunction and lung function impairment. Although having common signalling pathways, specific triggers and regulation mechanisms might be present in each disease. This review aims to describe the various mechanisms associated with fibrotic changes and airway remodelling involved in chronic airway diseases. Having better knowledge of the mechanisms underlying the EMT process may help us to identify specific targets and thus lead to the development of novel therapeutic strategies to prevent or limit the onset of irreversible structural changes.

The effects of the DASH dietary pattern on clinical outcomes and quality of life in adults with uncontrolled asthma: Design and methods of the ALOHA Trial

BACKGROUND

Poor diet quality is an important risk factor for increased asthma prevalence and poor asthma control. To address the question of whether adults with asthma can benefit from following a healthy diet, this trial will test the efficacy and mechanisms of action of a behavioral intervention promoting the Dietary Approaches to Stop Hypertension (DASH) dietary pattern with sodium reduction among patients with uncontrolled asthma.

METHODS

In this 2-arm randomized clinical trial, 320 racially/ethnically and socioeconomically diverse adults with uncontrolled asthma on standard controller therapy will be randomized to either a control or an intervention group and assessed at baseline, 3, 6 and 12 months. Control and intervention participants will receive education on lung health, asthma, and other general health topics; additionally, the intervention group will receive DASH behavioral counseling over 12 months. The primary hypothesis is that the DASH behavioral intervention, compared with the education-only control, will lead to significantly more participants with minimum clinically important improvement (responders) in asthma-specific quality of life at 12 months. Secondary hypotheses will test the intervention effects on other asthma (e.g., asthma control, lung function) and non-asthma outcomes (e.g., quality of life). Additionally, therapeutic (e.g., short chain fatty acids, cytokines) and nutritional biomarkers (e.g., dietary inflammatory index, carotenoids) will be assessed to understand the mechanisms of the intervention effect.

CONCLUSION

This trial can substantially advance asthma care by providing rigorous evidence on the benefits of a behavioral dietary intervention and mechanistic insights into the role of diet quality in asthma.

CLINICALTRIALS

gov #: NCT05251402.

Deletion of Miro1 in airway club cells potentiates allergic asthma phenotypes

Mitochondria are multifaceted organelles necessary for numerous cellular signaling and regulatory processes. Mitochondria are dynamic organelles, trafficked and anchored to subcellular sites depending upon the cellular and tissue requirements. Precise localization of mitochondria to apical and basolateral membranes in lung epithelial cells is important for key mitochondrial processes. Miro1 is an outer mitochondrial membrane GTPase that associates with adapter proteins and microtubule motors to promote intracellular movement of mitochondria. We show that deletion of Miro1 in lung epithelial cells leads to perinuclear clustering of mitochondria. However, the role of Miro1 in epithelial cell response to allergic insults remains unknown. We generated a conditional mouse model to delete Miro1 in Club Cell Secretory Protein (CCSP) positive lung epithelial cells to examine the potential roles of Miro1 and mitochondrial trafficking in the lung epithelial response to the allergen, house dust mite (HDM). Our data show that Miro1 suppresses epithelial induction and maintenance of the inflammatory response to allergen, as Miro1 deletion modestly induces increases in pro-inflammatory signaling, specifically IL-6, IL-33, CCL20 and eotaxin levels, tissue reorganization, and airway hyperresponsiveness. Furthermore, loss of Miro1 in CCSP+ lung epithelial cells blocks resolution of the asthmatic insult. This study further demonstrates the important contribution of mitochondrial dynamic processes to the airway epithelial allergen response and the pathophysiology of allergic asthma.

Mesenchymal stem cells and allergic airway inflammation; a therapeutic approach to induce immunoregulatory responses

Allergic airway inflammations are among the essential disorders worldwide that are already considered a significant concern. Mesenchymal stem cells (MSCs) are stromal cells with regenerative potential and immunomodulatory characteristics and are widely administered for tissue repair as an immunoregulatory agent in different inflammatory diseases. The current review summarized primary studies conducted to evaluate the therapeutic potential of MSCs for allergic airway disorders. In this case, modulation of airway pathologic inflammation and infiltration of inflammatory cells were examined, and modulation of the Th1/Th2 cellular balance and humoral responses. Also, the effects of MSCs on the Th17/Treg ratio and inducing Treg immunoregulatory responses along with macrophage and dendritic cell function were evaluated.

Involvement of Transforming Growth Factor-β-Associated Kinase 1 in Fixed Airway Obstruction in Asthmatic Patients with Longer Disease Duration Independent on Airway Eosinophilia

Objective

Transforming growth factor-β-associated kinase 1 (TAK1) mediates non-canonical TGF-β signalling by promoting adhesive, migratory, proliferative and contractile responses of fibroblasts to TGF-β₁. However, TAK1 expression status in asthmatic patients with or without fixed airway obstruction (FAO) is unknown.

Patients and Methods

A total of 60 adult asthmatics with FAO were recruited and compared to 43 those without FAO (nFAO). TGF-β₁ concentrations, and total TAK1 and phosphorylated TAK1 (p-TAK1) levels were determined in sputum supernatants, cytospin, and whole cell lysate by ELISA, immunocytochemistry, and Western blot analysis, respectively, in asthmatics with and without FAO.

Results

Asthmatic patients with FAO had much greater sputum TGF-β₁ concentrations than those without FAO. This was independent of airway eosinophilia as there was no significant difference in TGF-β₁ levels between high and low eosinophil counts within FAO and nFAO groups. In contrast, patients with FAO in the presence of sputum eosinophilia had greater expression of TAK1 and p-TAK1 than those without sputum eosinophilia (P=0.0032 and P=0.0061, respectively). The Western Blot data of total TAK1 and p-TAK1 were consistent with the immunocytochemistry, showing upregulation in all sputum cell types (neutrophils, eosinophils, macrophages, lymphocytes and airway epithelial cells). In addition, total TAK1 expression negatively correlated with pre- and post-bronchodilator FEV₁/FVC ratio.

Conclusion

TAK1 may play a key role in asthmatic patients with fixed airway obstruction, which was independent of eosinophilic airway inflammation. The interruption of TAK1 might have favourable clinical impact.

Anatomical and histopathological approaches to asthma phenotyping

Asthma is typically characterized by variable respiratory symptoms and airflow limitation. Along with the pathophysiology and symptoms are immunological and inflammatory processes. The last decades research has revealed that the immunology of asthma is highly heterogeneous. This has clinical consequences and identification of immunological phenotypes is currently used to guide biological treatment. The focus of this review is on another dimension of asthma diversity, namely anatomical heterogeneity. Immunopathological alterations may go beyond the central airways to also involve the distal airways, the alveolar parenchyma, and pulmonary vessels. Also, extrapulmonary tissues are affected. The anatomical distribution of inflammation in asthma has remained relatively poorly discussed despite its potential implication on both clinical presentation and response to treatment. There is today evidence that a significant proportion of the asthma patients has small airway disease with type 2 immunity, eosinophilia and smooth muscle infiltration of mast cells. The small airways in asthma are also subjected to remodelling, constriction, and luminal plugging, events that are likely to contribute to the elevated distal airway resistance seen in some patients. In cases when the inflammation extends into the alveolar parenchyma alveolar FCER1-high mast cells, eosinophilia, type 2 immunity and activated alveolar macrophages, together with modest interstitial remodelling, create a complex immunopathological picture. Importantly, the distal lung inflammation in asthma can be pharmacologically targeted by use of inhalers with more distal drug deposition. Biological treatments, which are readily distributed to the distal lung, may also be beneficial in eligible patients with more severe and anatomically widespread disease.

Subclinical high-resolution chest CT scan features in psoriasis

BACKGROUND

Although psoriasis is considered a systemic disease, no clear association has been established between psoriasis and lung diseases. This study aims to detect and describe subclinical pulmonary involvement in psoriasis patients with various degrees of cutaneous manifestations.

METHODS

Adult psoriasis patients with no known active pulmonary disease or respiratory symptoms were screened for subclinical pulmonary manifestations and possible parenchymal changes using high-resolution computed tomography (HRCT) scan of the chest. Patients were classified according to the severity of skin manifestations. The clinical characteristics and radiographic findings of these patients were evaluated.

RESULTS

Fifty-nine patients with psoriasis were included, among which 47 (79.7%) had abnormal HRCT scan features. Micronodules were the most common detected lung lesions (66.1%), followed by nonspecific interstitial changes (32.2%), including pleuro-parenchymal band/atelectasis, scarring, and focal ground-glass opacities. Other HRCT findings included emphysematous changes and calcified granulomas. Abnormal HRCT findings correlated with older age and duration of psoriasis but not with the severity of skin manifestations.

CONCLUSIONS

Micronodules and minor focal nonspecific interstitial changes were the most detected lung alterations in patients with psoriasis. These findings of the pilot study highlight a possible pulmonary involvement in patients with psoriasis. Larger multicenter studies are needed to clarify these findings further.

LIMITATIONS

A major limitation of the study, is the lack of a control group with similar radiologic findings of different conditions done in the same geographical region.

IGFBP-6 Network in Chronic Inflammatory Airway Diseases and Lung Tumor Progression

The lung is an accomplished organ for gas exchanges and directly faces the external environment, consequently exposing its large epithelial surface. It is also the putative determinant organ for inducing potent immune responses, holding both innate and adaptive immune cells. The maintenance of lung homeostasis requires a crucial balance between inflammation and anti-inflammation factors, and perturbations of this stability are frequently associated with progressive and fatal respiratory diseases. Several data demonstrate the involvement of the insulin-like growth factor (IGF) system and their binding proteins (IGFBPs) in pulmonary growth, as they are specifically expressed in different lung compartments. As we will discuss extensively in the text, IGFs and IGFBPs are implicated in normal pulmonary development but also in the pathogenesis of various airway diseases and lung tumors. Among the known IGFBPs, IGFBP-6 shows an emerging role as a mediator of airway inflammation and tumor-suppressing activity in different lung tumors. In this review, we assess the current state of IGFBP-6's multiple roles in respiratory diseases, focusing on its function in the inflammation and fibrosis in respiratory tissues, together with its role in controlling different types of lung cancer.

The effect of mitochondria-targeted slow hydrogen sulfide releasing donor AP39-treatment on airway inflammation

Mitochondrial dysfunction has been shown to contribute to the pathophysiology of airway diseases. Therefore, mitochondria are targeted in the development of new therapeutic approaches. Hydrogen sulfide (H₂S) has been shown to be involved in the pathophysiological processes of airway inflammation. We aimed to evaluate the effect of mitochondria-targeted slow H₂S releasing donor AP39 [(10-oxo-10-(4-(3-thioxo-3H-1,2-dithiol5yl)phenoxy)decyl)triphenylphosphoniumbromide)] on lipopolysaccharide (LPS)-induced airway inflammation in mice. LPS was applied to female Balb/c mice by intranasal (i.n.) route to induce airway inflammation and the subgroups of mice were treated with i.n. AP39 (250-1000 nmol/kg). 48 h after LPS administration airway reactivity was evaluated in vivo, then bronchoalveolar lavage (BAL) fluid and lungs were collected. LPS application led to bronchial hyperreactivity and neutrophil infiltration into the lung tissues along with increased TNF-α, IL-1β and IL-6 levels in BAL fluid. LPS also induced an increase in the rate of glycolysis, glycogenolysis and Krebs-cycle. AP39 treatment prevented the LPS-induced bronchial hyperreactivity and reversed the increase in TNF-α and IL-6 levels in BAL fluid. The increase in neutrophil numbers in BAL fluid was also prevented by AP39 treatment at the highest dose. Our results indicate that AP39 can prevent bronchial hyperreactivity and decrease airway inflammation. Targeting H₂S to the mitochondria may be a new therapeutic approach in airway inflammation.

Airway remodeling heterogeneity in asthma and its relationship to disease outcomes

Asthma affects an estimated 262 million people worldwide and caused over 461,000 deaths in 2019. The disease is characterized by chronic airway inflammation, reversible bronchoconstriction, and airway remodeling. Longitudinal studies have shown that current treatments for asthma (inhaled bronchodilators and corticosteroids) can reduce the frequency of exacerbations, but do not modify disease outcomes over time. Further, longitudinal studies in children to adulthood have shown that these treatments do not improve asthma severity or fixed airflow obstruction over time. In asthma, fixed airflow obstruction is caused by remodeling of the airway wall, but such airway remodeling also significantly contributes to airway closure during bronchoconstriction in acute asthmatic episodes. The goal of the current review is to understand what is known about the heterogeneity of airway remodeling in asthma and how this contributes to the disease process. We provide an overview of the existing knowledge on airway remodeling features observed in asthma, including loss of epithelial integrity, mucous cell metaplasia, extracellular matrix remodeling in both the airways and vessels, angiogenesis, and increased smooth muscle mass. While such studies have provided extensive knowledge on different aspects of airway remodeling, they have relied on biopsy sampling or pathological assessment of lungs from fatal asthma patients, which have limitations for understanding airway heterogeneity and the entire asthma syndrome. To further understand the heterogeneity of airway remodeling in asthma, we highlight the potential of in vivo imaging tools such as computed tomography and magnetic resonance imaging. Such volumetric imaging tools provide the opportunity to assess the heterogeneity of airway remodeling within the whole lung and have led to the novel identification of heterogenous gas trapping and mucus plugging as important predictors of patient outcomes. Lastly, we summarize the current knowledge of modification of airway remodeling with available asthma therapeutics to highlight the need for future studies that use in vivo imaging tools to assess airway remodeling outcomes.

Aquaporins in Respiratory System

Aquaporins (AQPs) are water channel proteins facilitating fluid transport in alveolar space, airway humidification, pleural fluid absorption, and submucosal gland secretion. In this chapter, we mainly focus on the expression of four AQPs in the lungs, which include AQP1, AQP2, AQP4, and AQP5 in normal and disease status, and the experience of AQPs function from various model and transgenic mice were summarized in detail to improve our understanding of the role of AQPs in fluid balance of respiratory system. It has been suggested that AQPs play important roles in various physiology and pathophysiology conditions of different lung diseases. There still remains unclear the exact role of AQPs in lung diseases, and thus continuous efforts on elucidating the roles of AQPs in lung physiological and pathophysiological processes are warranted.

Understanding fibroblast-immune cell interactions via co-culture models and their role in asthma pathogenesis

Asthma is a chronic lung disease involving airway inflammation and fibrosis. Fibroblasts are the main effector cells important for lung tissue production which becomes abnormal in asthmatics and is one of the main contributors to airway fibrosis. Although fibroblasts were traditionally viewed solely as structural cells, they have been discovered to be highly active, and involved in lung inflammatory and fibrotic processes in asthma. In line with this, using 2D and 3D in vitro co-culture models, a complex interaction between lung fibroblasts and various immune cells important for the pathogenesis of asthma have been recently uncovered. Hence, in this review, we provide the first-ever summary of various studies that used 2D and 3D in vitro co-culture models to assess the nature of aberrant immune cell-fibroblast interactions and their contributions to chronic inflammation and fibrotic mechanisms in asthma pathogenesis.

Biologics and airway remodeling in severe asthma

Asthma is a chronic inflammatory airway disease resulting in airflow obstruction, which in part can become irreversible to conventional therapies, defining the concept of airway remodeling. The introduction of biologics in severe asthma has led in some patients to the complete normalization of previously considered irreversible airflow obstruction. This highlights the need to distinguish a "fixed" airflow obstruction due to structural changes unresponsive to current therapies, from a "reversible" one as demonstrated by lung function normalization during biological therapies not previously obtained even with high-dose systemic glucocorticoids. The mechanisms by which exposure to environmental factors initiates the inflammatory responses that trigger airway remodeling are still incompletely understood. Alarmins represent epithelial-derived cytokines that initiate immunologic events leading to inflammatory airway remodeling. Biological therapies can improve airflow obstruction by addressing these airway inflammatory changes. In addition, biologics might prevent and possibly even revert "fixed" remodeling due to structural changes. Hence, it appears clinically important to separate the therapeutic effects (early and late) of biologics as a new paradigm to evaluate the effects of these drugs and future treatments on airway remodeling in severe asthma.

STAT6-IP-Dependent Disruption of IL-33-Mediated ILC2 Expansion and Type 2 Innate Immunity in the Murine Lung

Recent interest has focused on innate-type cytokines as promoters of type 2 immunity and targets for drug development in asthma. IL-33 induces production of IL-4 and/or IL-13, which is associated with STAT6-dependent responses in innate cells, including group 2 innate lymphoid cells (ILC2s), macrophages, and eosinophils. Our published data show that STAT6-immunomodulatory peptide (STAT6-IP), an immunomodulatory peptide designed to inhibit the STAT6 transcription factor, reduces induction of Th2 adaptive immunity in respiratory syncytial virus infection and asthma models. Nevertheless, the mechanism of STAT6-IP-dependent inhibition has remained obscure. In this study, we demonstrate that STAT6-IP reduced IL-33-induced type 2 innate lung inflammation. Specifically, our data show that STAT6-IP reduced recruitment and activation of eosinophils as well as polarization of alternatively activated macrophages. Decreases in these cells correlated with reduced levels of IL-5 and IL-13 as well as several type 2 chemokines in the bronchoalveolar lavage fluid. STAT6-IP effectively inhibited expansion of ILC2s as well as the number of IL-5- and IL-13-producing ILC2s. Our data suggest that STAT6-IP effectively disrupts IL-13-dependent positive feedback loops, initiated by ILC2 activation, to suppress IL-33-induced type 2 innate immunity in the murine lung.

Anti-asthmatic fraction screening and mechanisms prediction of Schisandrae Sphenantherae Fructus based on a combined approach

Objective: Schisandrae Sphenantherae Fructus (SSF) is a traditional Chinese medicine used to treat coughs and pulmonary inflammatory diseases. However, the pharmacodynamic material basis and mechanisms for SSF in asthma treatment remain unclear. This study aims to screen the anti-asthmatic fraction and verify the pharmacodynamic material basis, predict the potential mechanism, and verify the interaction ability between compounds and core targets.

Methods: First, three fractions from SSF were compared in terms of composition, comparison, and anti-asthmatic effects. Then, the ultra-performance liquid chromatography-quadrupole/time-of-flight-mass spectrometry/mass spectrometry (UPLC-Q/TOF-MS/MS) strategy was used to identify the compounds from the active fraction, and the anti-asthmatic efficacy of the active fraction was further studied by the ovalbumin (OVA)-induced asthma murine model. Finally, network pharmacology and molecular methods were used to study the relationships between active compounds, core targets, and key pathways of PEF in asthma treatments.

Results: The petroleum ether fraction (PEF) of SSF showed better effects and could significantly diminish lung inflammation and mitigate the level of serum immunoglobulin E (IgE), interleukin (IL)-4, IL-5, IL-6, IL-13, and IL-17 in mice. A total of 26 compounds from the PEF were identified, among which the main compounds are lignans and triterpenes. Moreover, 21 active compounds, 129 overlap-ping targets, and 10 pathways were screened by network pharmacology tools. The top five core targets may play a great role in asthma treatment. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis suggested that the PEF can treat asthma by acting on multiple asthma pathological processes, including the IL-17 signaling pathway, T helper (Th) 17 cell differentiation, and the calcium signaling pathway. Molecular docking was performed to evaluate the interactions of the protein–ligand binding, and most docked complexes had a good binding ability.

Conclusion: The present results might contribute to exploring the active compounds with anti-asthmatic activity.

Neutrophil Extracellular Traps Are Found in Bronchoalveolar Lavage Fluids of Horses With Severe Asthma and Correlate With Asthma Severity

Asthma encompasses a spectrum of heterogenous immune-mediated respiratory disorders sharing a similar clinical pattern characterized by cough, wheeze and exercise intolerance. In horses, equine asthma can be subdivided into severe or moderate asthma according to clinical symptoms and the extent of airway neutrophilic inflammation. While severe asthmatic horses are characterized by an elevated neutrophilic inflammation of the lower airways, cough, dyspnea at rest and high mucus secretion, horses with moderate asthma show a milder neutrophilic inflammation, exhibit intolerance to exercise but no labored breathing at rest. Yet, the physiopathology of different phenotypes of equine asthma remains poorly understood and there is a need to elucidate the underlying mechanisms tailoring those phenotypes in order to improve clinical management and elaborate novel therapeutic strategies. In this study, we sought to quantify the presence of neutrophil extracellular traps (NETs) in bronchoalveolar lavage fluids (BALF) of moderate or severe asthmatic horses and healthy controls, and assessed whether NETs correlated with disease severity. To this end, we evaluated the amounts of NETs by measuring cell-free DNA and MPO-DNA complexes in BALF supernatants or by quantifying NETs release by BALF cells by confocal microscopy. We were able to unequivocally identify elevated NETs levels in BALF of severe asthmatic horses as compared to healthy controls or moderate asthmatic horses. Moreover, we provided evidence that BALF NETs release was a specific feature seen in severe equine asthma, as opposed to moderate asthma, and correlated with disease severity. Finally, we showed that NETs could act as a predictive factor for severe equine asthma. Our study thus uniquely identifies NETs in BALF of severe asthmatic horses using three distinct methods and supports the idea that moderate and severe equine asthma do not rely on strictly similar pathophysiological mechanisms. Our data also suggest that NETs represent a relevant biomarker, a putative driver and a potential therapeutic target in severe asthma disease.

The Interaction Network of MicroRNAs with Cytokines and Signaling Pathways in Allergic Asthma

Allergic asthma is a complicated disease that is affected by many factors. Numerous cytokines and signaling pathways are attributed to the cause of asthma symptoms. MicroRNAs (miRNAs) are a group of small non-coding single-stranded RNA molecules that are involved in gene silencing and posttranscriptional regulation of gene expression by targeting mRNAs. In pathological conditions, altered expression of microRNAs differentially regulates cytokines and signaling pathways and therefore, can be the underlying reason for the pathogenesis of allergic asthma. Indeed, microRNAs participate in airway inflammation via inducing airway structural cells and activating immune responses by targeting cytokines and signaling pathways. Thus, to make a complete understanding of allergic asthma, it is necessary to investigate the communication network of microRNAs with cytokines and signaling pathways which is contributed to the pathogenesis of allergic asthma. Here, we shed light on this aspect of asthma pathology by Summarizing our current knowledge of this topic.

Cytokine TGFβ Gene Polymorphism in Asthma: TGF-Related SNP Analysis Enhances the Prediction of Disease Diagnosis (A Case-Control Study With Multivariable Data-Mining Model Development)

Introduction

TGF-β and its receptors play a crucial role in asthma pathogenesis and bronchial remodeling in the course of the disease. TGF-β1, TGF-β2, and TGF-β3 isoforms are responsible for chronic inflammation, bronchial hyperreactivity, myofibroblast activation, fibrosis, bronchial remodeling, and change the expression of approximately 1000 genes in asthma. TGF-β SNPs are associated with the elevated plasma level of TGF-β1, an increased level of total IgE, and an increased risk of remodeling of bronchi.

Methods

The analysis of selected TGF-β1, TGF-β2, TGF-β3-related single-nucleotide polymorphisms (SNP) was conducted on 652 DNA samples with an application of the MassARRAY® using the mass spectrometry (MALDI-TOF MS). Dataset was randomly split into training (80%) and validation sets (20%). For both asthma diagnosis and severity prediction, the C5.0 modelling with hyperparameter optimization was conducted on: clinical and SNP data (Clinical+TGF), only clinical (OnlyClinical) and minimum redundancy feature selection set (MRMR). Area under ROC (AUCROC) curves were compared using DeLong’s test.

Results

Minor allele carriers (MACs) in SNP rs2009112 [OR=1.85 (95%CI:1.11-3.1), p=0.016], rs2796821 [OR=1.72 (95%CI:1.1-2.69), p=0.017] and rs2796822 [OR=1.71 (95%CI:1.07-2.71), p=0.022] demonstrated an increased odds of severe asthma. Clinical+TGF model presented better diagnostic potential than OnlyClinical model in both training (p=0.0009) and validation (AUCROC=0.87 vs. 0.80,p=0.0052). At the same time, the MRMR model was not worse than the Clinical+TGF model (p=0.3607 on the training set, p=0.1590 on the validation set), while it was better in comparison with the Only Clinical model (p=0.0010 on the training set, p=0.0235 on validation set, AUCROC=0.85 vs. 0.87). On validation set Clinical+TGF model allowed for asthma diagnosis prediction with 88.4% sensitivity and 73.8% specificity.

Discussion

Derived predictive models suggest the analysis of selected SNPs in TGF-β genes in combination with clinical factors could predict asthma diagnosis with high sensitivity and specificity, however, the benefit of SNP analysis in severity prediction was not shown.

Expert Opinion on Practice Patterns in Mild Asthma After the GINA 2019 Updates: A Major Shift in Treatment Paradigms from a Long-Standing SABA-Only Approach to a Risk Reduction-Based Strategy with the Use of Symptom-Driven (As-Needed) Low-Dose ICS/LABA

PURPOSE OF REVIEW

This expert opinion, prepared by a panel of chest disease specialists, aims to review the current knowledge on practice patterns in real-life management of mild asthma and to address the relevant updates in asthma treatment by The Global Initiative for Asthma (GINA) to guide clinicians for the best clinical practice in applying these new treatment paradigms.

RECENT FINDINGS

On the basis of the emerging body of evidence suggesting the non-safety of short-acting β2-agonists (SABA)-only therapy and comparable efficacy of the as-needed inhaled corticosteroids (ICS)-formoterol combinations with maintenance ICS regimens, GINA recently released their updated Global Strategy for Asthma Management and Prevention Guide (2019). The new GINA 2019 recommendations no longer support the SABA-only therapy in mild asthma but instead includes new off-label recommendations such as symptom-driven (as-needed) low-dose ICS-formoterol and "low dose ICS taken whenever SABA is taken." The GINA 2019 asthma treatment recommendations include a major shift from long-standing approach of clinical practice regarding the use of symptom-driven SABA treatment alone in the management of mild asthma. This expert opinion supports the transition from a long-standing SABA-only approach to a risk reduction-based strategy, with the use of symptom-driven (as-needed) low-dose ICS/LABA in mild asthma patients, particularly in those with poor adherence to controller medications. The thoughtful and comprehensive approach of clinicians to these strategies is important, given that the exact far-reaching impact of this major change in management of mild asthma in the real-world settings will only be clarified over time.

Title-Inflammatory Signaling Pathways in Allergic and Infection-Associated Lung Diseases

Lung inflammation can be caused by pathogen infection alone or by allergic disease, leading to pneumonitis. Most of the allergens (antigens) that cause allergic lung diseases, including asthma and hypersensitivity pneumonitis (HP), are derived from microorganisms, such as bacteria, viruses, and fungi, but some inorganic materials, such as mercury, can also cause pneumonitis. Certain allergens, including food and pollen, can also cause acute allergic reactions and lead to lung inflammation in individuals predisposed to such reactions. Pattern recognition-associated and damage-associated signaling by these allergens can be critical in determining the type of hypersensitization and allergic disease, as well as the potential for fibrosis and irreversible lung damage. This review discusses the signs, symptoms, and etiology of allergic asthma, and HP. Furthermore, we review the immune response and signaling pathways involved in pneumonitis due to both microbial infection and allergic processes. We also discuss current and potential therapeutic interventions for infection-associated and allergic lung inflammation.

Gastric motility and pulmonary function in children with functional abdominal pain disorders and asthma: A pathophysiological study

Background

An association has been shown between functional abdominal pain disorders (FAPDs) and asthma. However, the exact reason for this association is obscured. The main objective of this study is to identify the possible underlying pathophysiological mechanisms for the association between FAPDs and asthma using gastric motility and lung function tests.

Methods

This was a cross-sectional comparative study that consisted of four study groups. Twenty-four children (age 7–12 years) each were recruited for four study groups; asthma only, FAPDs only, both asthma and FAPDs, and healthy controls. Asthma was diagnosed using the history and bronchodilator reversibility test. The diagnosis of FAPDs was made using Rome IV criteria. All subjects underwent ultrasound assessment of gastric motility and pulmonary function assessment by spirometry, using validated techniques.

Results

All gastric motility parameters, gastric emptying rate, amplitude of antral contraction, and antral motility index, were significantly impaired in children with FAPDs only, children with asthma only, and children with both asthma & FAPDs, compared to controls (p<0.05). Pulmonary function parameters indicating airway obstruction (FEV₁/FVC ratio, peak expiratory flow rate, FEF25-75%) were not impaired in children with FAPDs only compared to controls (p>0.05), but significantly impaired in children with asthma and children with both disorders. Antral motility index correlated with the FEV₁/FVC ratio (r = 0.60, p = 0.002) and FEF25%-75% (r = 0.49, p = 0.01) in children with both asthma and FAPDs.

Conclusions

Gastric motor functions were significantly impaired in children with asthma, children with FAPDs, and children with both disorders. Motility index, measuring overall gastric motor activity, showed a significant positive correlation with lung function parameters that measure airflow limitation. Therefore, these diseases might arise as a result of primary disturbance of smooth muscle activity in the airways and gastrointestinal wall, which could be a possible pathophysiological mechanism for this association between asthma and FAPDs.

Methods to Detect Neutrophil Extracellular Traps in Asthma

Neutrophil extracellular traps (NETs) have the ability to regulate many aspects of asthma pathology. NETs can be detected either in bronchoalveolar lavage fluids (BALF) or in lung biopsies. Here, we describe methods to quantify NETs in BALF, namely the quantification of cell-free DNA, or of myeloperoxidase (MPO) or neutrophil elastase (NE) complexed with cell-free DNA. We also explain how to detect NETs in lung biopsies by two distinct techniques. The first technique is based on quantification of the citrullinated form of histone 3 (Cit-H3 , a specific component of NET) by western blot on tissue protein extracts. The second technique is based on the visualization of extracellular structures composed of MPO co-localizing with Cit-H3 in tissue sections by confocal microscopy. Finally, we describe a method allowing for quantification of NET volume in lung sections.

Involvement of polycyclic aromatic hydrocarbons and endotoxin in macrophage expression of interleukin-33 induced by exposure to particulate matter

Air pollutants are important factors that contribute to the development and/or exacerbation of allergic inflammation accompanied by asthma, but experimental evidence still needs to be collected. Interleukin 33 (IL-33) is closely involved in the onset and progression of asthma. In this study, we examined the effects of particulate matter (PM) on IL-33 expression in macrophages. PM2.5 collected in Yokohama, Japan by the cyclone device significantly induced IL-33 expression in human THP-1 macrophages, and the induction was clearly suppressed by pretreatment with the aryl hydrocarbon receptor (AhR) antagonist CH-223191 or the Toll-like receptor 4 (TLR4) antagonist TAK-242. PM2.5-induced IL-33 expression was significantly attenuated in AhR-knockout or TLR4-mutated macrophages, suggesting an important role of polycyclic aromatic hydrocarbons (PAHs) and endotoxin in IL-33 stimulation. PM samples derived from tunnel dust slightly but significantly induced IL-33 expression, while road dust PM did not affect IL-33 expression. The PAH concentration in tunnel dust was higher than that in road dust. Tunnel dust or road dust PM contained less endotoxin than PM2.5 collected in Yokohama. These data suggest that the potency of IL-33 induction could depend on the concentration of PAHs as well as endotoxin in PMs. Caution regarding PAHs and endotoxin levels in air pollutants should be taken to prevent IL-33-induced allergic inflammation.

Effects of high intensity interval training on cardiorespiratory fitness and salivary levels of IL-8, IL-1ra, and IP-10 in adults with asthma and non-asthma controls

OBJECTIVE

The purpose of this study was to determine whether high intensity interval training (HIIT) would lead to improvements in 1) maximal VO₂, V_E, V_E/VCO₂, and V_E/MVV, and/or 2) resting salivary concentrations of pro-inflammatory markers Interleukin (IL-8), interferon-gamma-inducible-protein (CXCL10/IP-10)) and anti-inflammatory marker IL-1 receptor antagonist (IL-1ra) in adults with well-controlled asthma compared to non-asthma controls.

METHODS

Participants completed a maximal exercise test at the beginning (T1) and end (T2) of a 6-week HIIT intervention; saliva samples were obtained at the beginning and 30 min following the first (T1) and last (T2) exercise session.

RESULTS

Adults with asthma (n = 20; age: 21.4 ± 2.4 years) and non-asthma controls (n = 12; age: 22.5 ± 3.4 years) completed the intervention. VO₂max increased from T1 to T2 in both groups (asthma T1 32.9 ± 8, T2 38.6 ± 8.2 ml/kg/min; controls T1 34.5 ± 11.8, T2 38.9 ± 12.3 ml/kg/min). V_Emax also increased in both groups (asthma T1 97.7, T2 110.8 units, p < 0.001, h_p² = <0.04; control T1 106.3, T2 118.1, p < 0.001, h_p² 0.02). An increase in V_E/VCO₂ (F(1, 10)=22.11, p = 0.001) and V_E/MVV (F(1, 10) = 111.30, p < 0.001) was observed in the control group; no differences were observed in the asthma group. No differences in IL-8 or IL-1ra were observed between groups. In the asthma group, resting salivary IP-10 concentrations significantly decreased from T1 (0.025 pg/ug protein) to T2 (0.015 pg/ug protein, p = 0.039, h_p² = 0.3 (moderate effect)).

CONCLUSION

A 6-week HIIT intervention led to a similar increase in VO₂max and V_Emax in those with and without asthma, and a decrease in resting salivary IP-10 levels among adults with asthma.

MicroRNA-mediated calcineurin signaling activation induces CCL2, CCL3, CCL5, IL8, and chemotactic activities in 4,4'-methylene diphenyl diisocyanate exposed macrophages

Occupational exposure to 4,4'-methylene diphenyl diisocyanate (MDI), the most widely used monomeric diisocyanate, is one of the leading causes of occupational asthma (OA). Previously, we identified microRNA (miR)-206-3p/miR-381-3p-mediated PPP3CA/calcineurin signalling regulated iNOS transcription in macrophages and bronchoalveolar lavage cells (BALCs) after acute MDI exposure; however, whether PPP3CA/calcineurin signalling participates in regulation of other asthma-associated mediators secreted by macrophages/BALCs after MDI exposure is unknown.Several asthma-associated, macrophage-secreted mediator mRNAs from MDI exposed murine BALCs and MDI-glutathione (GSH) conjugate treated differentiated THP-1 macrophages were analysed using RT-qPCR.Endogenous IL1B, TNF, CCL2, CCL3, CCL5, and TGFB1 were upregulated in MDI or MDI-GSH conjugate exposed BALCs and macrophages, respectively. Calcineurin inhibitor tacrolimus (FK506) attenuated the MDI-GSH conjugate-mediated induction of CCL2, CCL3, CCL5, and CXCL8/IL8 but not others. Transfection of either miR-inhibitor-206-3p or miR-inhibitor-381-3p in macrophages induced chemokine CCL2, CCL3, CCL5, and CXCL8 transcription, whereas FK506 attenuated the miR-inhibitor-206-3p or miR-inhibitor-381-3p-mediated effects. Finally, MDI-GSH conjugate treated macrophages showed increased chemotactic ability to various immune cells, which may be attenuated by FK506.In conclusion, these results indicate that MDI exposure to macrophages/BALCs may recruit immune cells into the airway via induction of chemokines by miR-206-3p and miR-381-3p-mediated calcineurin signalling activation.

Association between Glucose-6-Phosphate Dehydrogenase Deficiency and Asthma

Background: Among the determinants contributing to the pathogenesis of asthma, antioxidant genetic factors play a leading role. Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme that is competent to detoxify free radicals. Although a relationship between G6PD deficiency and asthma has been previously reported, the literature is still scanty. In this study, we test this hypothesis in a large cohort of patients from Sardinia, Italy. Methods: A retrospective case–control study was performed using data from 11,829 clinical records of outpatients referred to a teaching hospital for a medical visit. In total, 455 cases (asthma-positive) and 11,374 controls (asthma-negative) were compared for G6PD status using multivariable analysis, adjusting for all covariates. Results: Overall, G6PD deficiency was detected in 11.2% of study participants and was associated with an increased risk of asthma (odds ratio (OR) 1.63; 95% confidence interval (CI) 1.27–2.10). Additional variables significantly associated with asthma were female sex (OR 1.66; 95% CI 1.34–2.06), overweight/obesity (OR 1.56; 95% CI 1.27–1.92), smoking (OR 1.44; 95% CI 1.449–3.963), and high socioeconomic status (OR 1.40; 95% CI 1.16–1.70), whereas age was inversely related with asthma (OR 0.49; 95% CI 0.39–0.61). Conclusions: Our study shows that G6PD deficiency is an independent risk for asthma. These findings suggest that G6PD should be assessed in asthmatic patients for better risk stratification.

Allergic Inflammation Caused by Dimerized Translationally Controlled Tumor Protein is Attenuated by Cardamonin

We demonstrated in our previous reports that dimeric form of translationally controlled tumor protein (dTCTP) initiates a variety of allergic phenomena. In the present study, we examined whether and how dTCTP's role in allergic inflammation can be modulated or negated. The possible potential of cardamonin as an anti-allergic agent was assessed by ELISA using BEAS-2B cells and OVA-challenged allergic mouse model. The interaction between cardamonin and dTCTP was confirmed by SPR assay. Cardamonin was found to reduce the secretion of IL-8 caused by dTCTP in BEAS-2B cells by interacting with dTCTP. This interaction between dTCTP and cardamonin was confirmed through kinetic analysis (K_D = 4.72 ± 0.07 μM). Also, cardamonin reduced the migration of various inflammatory cells in the bronchoalveolar lavage fluid (BALF), inhibited OVA specific IgE secretion and bronchial remodeling. In addition, cardamonin was observed to have an anti-allergic response by inhibiting the activity of NF-κB. Cardamonin exerts anti-allergic anti-inflammatory effect by inhibiting dTCTP, suggesting that it may be useful in the therapy of allergic diseases.

The efficacy of Nigella sativa supplementation for asthma control: a meta-analysis of randomized controlled studies

Introduction

The efficacy of Nigella sativa supplementation for asthma control remains controversial. We have conducted a systematic review and meta-analysis to explore the influence of Nigella sativa supplementation on asthma control.

Material and methods

We have searched PubMed, EMBASE, Web of science, EBSCO, and Cochrane library databases through June 2019 for randomized controlled trials (RCTs) assessing the efficacy of Nigella sativa supplementation for asthma control.

Results

Four RCTs are included in the meta-analysis. Overall, compared with the control group for asthma, Nigella sativa supplementation is associated with the increased ACT scores (SMD = 0.50; 95% CI: 0.11–0.88; p = 0.01), and FEV1 (SMD = 1.84; 95% CI: 0.07–3.60; p = 0.04), but demonstrates no obvious impact on PEF (SMD = 3.11; 95% CI: –1.30 to 7.52; p = 0.17), IL-4 (SMD = –0.31; 95% CI: –1.21 to 0.59; p = 0.50), or IFN-γ (SMD = 1.11; 95% CI: –0.44 to 2.67; p = 0.16).

Conclusions

Nigella sativa supplementation may provide additional benefits for the treatment of asthma.

The impact of CRTH2 antagonist OC 000459 on pulmonary function of asthma patients: a meta-analysis of randomized controlled trials

Introduction

The chemoattractant receptor expressed on T-helper (Th) type 2 cells (CRTH2) antagonist OC 000459 showed the potential in improving pulmonary function of asthma patients.

Aim

We conducted a systematic review and meta-analysis to explore the impact of CRTH2 antagonist OC 000459 on pulmonary function for asthma.

Material and methods

PubMed, Embase, Web of science, EBSCO, and Cochrane library databases were systematically searched. This meta-analysis included randomized controlled trials (RCTs) assessing the effect of CRTH2 antagonist OC 000459 on pulmonary function for asthma. Two investigators independently searched articles, extracted data, and assessed the quality of included studies.

Results

Four RCTs were included in the meta-analysis. Overall, compared with the control intervention for asthma patients, CRTH2 antagonist OC 000459 could significantly improve FEV₁ (SMD = 0.22; 95% CI: 0.02–0.42; p = 0.03), peak expiratory flow (SMD = 0.22; 95% CI: 0.01–0.42; p = 0.04) and reduce the respiratory tract infection (RR = 0.47; 95% CI: 0.26–0.85; p = 0.01), but revealed no remarkable effect on predicted FEV₁ (SMD = 0.14; 95% CI: –0.18 to 0.45; p = 0.39), or treatment-related adverse events (RR = 0.84; 95% CI: 0.52–1.36; p = 0.48).

Conclusions

CRTH2 antagonist OC 000459 might be effective and safe to improve pulmonary function in asthma patients.

Anxiety, depression, and asthma: New perspectives and approaches for psychoneuroimmunology research

The field of psychoneuroimmunology has advanced the understanding of the relationship between immunology and mental health. More work can be done to advance the field by investigating the connection between internalizing disorders and persistent airway inflammation from asthma and air pollution exposure. Asthma is a prominent airway condition that affects about 10% of developing youth and 7.7% of adults in the United States. People who develop with asthma are at three times increased risk to develop internalizing disorders, namely anxiety and depression, compared to people who do not have asthma while developing. Interestingly, sex differences also exist in asthma prevalence and internalizing disorder development that differ based on age. Exposure to air pollution also is associated with increased asthma and internalizing disorder diagnoses. New perspectives of how chronic inflammation affects the brain could provide more understanding into internalizing disorder development. This review on how asthma and air pollution cause chronic airway inflammation details recent preclinical and clinical research that begins to highlight potential mechanisms that drive comorbidity with internalizing disorder symptoms. These findings provide a foundation for future studies to identify therapies that can simultaneously treat asthma and internalizing disorders, thus potentially decreasing mental health diagnoses in asthma patients.

Der p 38 Is a Bidirectional Regulator of Eosinophils and Neutrophils in Allergy

The house dust mite is the most common cause of allergic diseases, and TLR4 acts as an overarching receptor for allergic responses. This study aimed to identify novel allergen binding to TLR4 in house dust mites and unveil its unique role in allergic responses. Der p 38 was purified and characterized by liquid chromatography tandem mass spectrometry-based peptide mapping. Biolayer interferometry and structure modeling unveiled TLR4-binding activity and the structure of recombinant Der p 38. The allergenicity of Der p 38 was confirmed by a skin prick test, and basophil activation and dot blot assays. The skin prick test identified 24 out of 45 allergic subjects (53.3%) as Der p 38⁺ subjects. Der p 38-augmented CD203c expression was noted in the basophils of Der p 38⁺ allergic subjects. In animal experiments with wild-type and TLR4 knockout BALB/c mice, Der p 38 administration induced the infiltration of neutrophils as well as eosinophils and exhibited clinical features similar to asthma via TLR4 activation. Persistent Der p 38 administration induced severe neutrophil inflammation. Der p 38 directly suppressed the apoptosis of allergic neutrophils and eosinophils, and enhanced cytokine production in human bronchial epithelial cells, inhibiting neutrophil apoptosis. The mechanisms involved TLR4, LYN, PI3K, AKT, ERK, and NF-κB. These findings may contribute to a deep understanding of Der p 38 as a bridge allergen between eosinophilic and neutrophilic inflammation in the pathogenic mechanisms of allergy.

Hypertensive disorders in pregnancy and risk of asthma in offspring: a systematic review and meta-analysis

OBJECTIVES

The association between hypertensive disorders in pregnancy (HDP) and an increased risk of asthma in offspring remains controversial. No systematic review of this topic has been performed. The aim of this systematic review was to summarise the available evidence regarding the association between HDP and the risk of asthma in offspring.

DESIGN

Systematic review and meta-analysis.

METHODS

On the basis of a prepared protocol, a systematic search of PubMed, EMBASE, the Cochrane Library and Web of Science was performed using a detailed search strategy from the database inception to 17 January 2020. Cohort, case-control and cross-sectional studies published in English reporting the diagnoses of maternal HDP and asthma in offspring were included. The Meta-analysis of Observational Studies in Epidemiology guidelines were followed throughout the study. The estimated pooled ORs of HDP and asthma in offspring were calculated from the studies, and the meta-analysis was performed using random-effects models.

RESULTS

Ten cohort studies involving a total of 6 270 430 participants were included. According to the Newcastle-Ottawa Scale, the overall methodological quality was good since 8 studies were of high quality and 2 studies were of moderate quality. After controlling for potential confounders, HDP was associated with a possible increased risk of asthma in offspring, with a pooled adjusted OR (aOR) of 1.19 (95% CI 1.12 to 1.26). The subgroup analyses according to HDP subgroups, sibling design, study quality, study location, offspring ages, singleton status, exposure assessment, outcome assessment and adjusted factors showed similar results.

CONCLUSIONS

Exposure to HDP may be associated with an increased risk of asthma in offspring. Further research is needed to verify the results and determine whether the observed relationship is causal.

PROSPERO REGISTRATION NUMBER

CRD42020148250.

An optimized derivative of an endogenous CXCR4 antagonist prevents atopic dermatitis and airway inflammation

Aberrant CXCR4/CXCL12 signaling is involved in many pathophysiological processes such as cancer and inflammatory diseases. A natural fragment of serum albumin, named EPI-X4, has previously been identified as endogenous peptide antagonist and inverse agonist of CXCR4 and is a promising compound for the development of improved analogues for the therapy of CXCR4-associated diseases. To generate optimized EPI-X4 derivatives we here performed molecular docking analysis to identify key interaction motifs of EPI-X4/CXCR4. Subsequent rational drug design allowed to increase the anti-CXCR4 activity of EPI-X4. The EPI-X4 derivative JM#21 bound CXCR4 and suppressed CXCR4-tropic HIV-1 infection more efficiently than the clinically approved small molecule CXCR4 antagonist AMD3100. EPI-X4 JM#21 did not exert toxic effects in zebrafish embryos and suppressed allergen-induced infiltration of eosinophils and other immune cells into the airways of animals in an asthma mouse model. Moreover, topical administration of the optimized EPI-X4 derivative efficiently prevented inflammation of the skin in a mouse model of atopic dermatitis. Thus, rationally designed EPI-X4 JM#21 is a novel potent antagonist of CXCR4 and the first CXCR4 inhibitor with therapeutic efficacy in atopic dermatitis. Further clinical development of this new class of CXCR4 antagonists for the therapy of atopic dermatitis, asthma and other CXCR4-associated diseases is highly warranted.