Pathogenesis Of Allergic Asthma Research Articles

Iron-related Genes and Proteins Involved in Iron Homeostasis in Animal Models of Allergic Asthma: A Systematic Review.

The involvement of the immune oxidative stress response in the pathophysiology and pathogenesis of allergic asthma is well documented. However, reports on the role of iron homeostasis in allergic asthma is scarce. Therefore, this study aims to identify iron-related genes and proteins in mouse models of allergic asthma. Related articles were identified from SCOPUS and Web of Science databases. The article search was limited to publications in English, within a 10-year period (2014 - 2023, up to 16 August 2023) and original/research papers. All identified articles were screened for eligibility using the inclusion and exclusion criteria. All eligible articles were quality appraised prior to data extraction. Five studies were selected for data extraction. Based on the extracted data, three themes and seven subthemes related to iron homeostasis were identified. The type of samples and analytical methods used were also identified. In conclusion, our study elucidates that iron-related proteins are regulated in animal models of allergic asthma. However, the currently available data do not allow us to conclude whether the disease model resulted in iron accumulation or depletion. Therefore, further studies with other related markers should be conducted.

The barrier-protective effect of β-eudesmol against type 2-inflammatory cytokine-induced tight junction disassembly in airway epithelial cells.

Allergic inflammation, which is the pathogenesis of allergic rhinitis and asthma, is associated with disruption of the airway epithelial barrier due to the effects of type 2 inflammatory cytokines, i.e. interleukin-4 and interleukin-13 (IL-4/13). The anti-allergic inflammatory effect of β-eudesmol (BE) on the tight junction (TJ) of the airway epithelium has not previously been reported. Herein, the barrier protective effect of BE was determined by measurement of transepithelial electrical resistance and by paracellular permeability assay in an IL-4/13-treated 16HBE14o- monolayer. Pre-treatment of BE concentration- and time- dependently inhibited IL-4/13-induced TJ barrier disruption, with the most significant effect observed at 20 μM. Cytotoxicity analyses showed that BE, either alone or in combination with IL-4/13, had no effect on cell viability. Western blot and immunofluorescence analyses showed that BE inhibited IL-4/13-induced mislocalization of TJ components, including occludin and zonula occludens-1 (ZO-1), without affecting the expression of these two proteins. In addition, the mechanism of the TJ-protective effect of BE was mediated by inhibition of IL-4/13-induced STAT6 phosphorylation, in which BE might serve as an antagonist of cytokine receptors. In silico molecular docking analysis demonstrated that BE potentially interacted with the site I pocket of the type 2 IL-4 receptor, likely at Asn-126 and Tyr-127 amino acid residues. It can therefore be concluded that BE is able to prevent IL-4/13-induced TJ disassembly by interfering with cytokine-receptor interaction, leading to suppression of STAT6-induced mislocalization of occludin and ZO-1. BE is a promising candidate for a therapeutic intervention for inflammatory airway epithelial disorders driven by IL-4/13.

Hispidulin Alleviates Mast Cell-Mediated Allergic Airway Inflammation through FcεR1 and Nrf2/HO-1 Signaling Pathway.

Allergic asthma is a type 2 immune-response-mediated chronic respiratory disease. Mast cell activation influences the pathogenesis and exacerbation of allergic asthma. Therefore, the development of mast cell-targeting pharmacotherapy is important for managing allergic airway inflammation. We investigated the efficacy of hispidulin (HPD), natural flavone, in a mast-cell-mediated ovalbumin (OVA)-induced allergic airway inflammation model. HPD alleviated symptoms of allergic asthma and decreased the levels of immunoglobulin (Ig) E, type 2 inflammation, immune cell infiltration, and mast cell activation in the lung. Furthermore, in vivo analysis confirmed the efficacy of HPD through the evaluation of IgE-mediated allergic responses in a mast cell line. HPD treatment inhibited mast cell degranulation through inhibition of the FcεR1 signaling pathway and suppressed the expression of inflammatory cytokines (TNF-α, IL-4, IL-6, and IL-13) through suppression of the NF-κB signaling pathway. The antioxidant effects of HPD in activated mast cells were identified through modulation of antioxidant enzymes and the Nrf2/HO-1 signaling pathway. In conclusion, HPD may be a potential therapeutic candidate for allergic airway inflammation of asthma and acts by suppressing mast cell activation and oxidative stress.

Dimethyl fumarate alleviates allergic asthma by strengthening the Nrf2 signaling pathway in regulatory T cells.

Allergic asthma is a widely prevalent inflammatory condition affecting people across the globe. T cells and their secretory cytokines are central to the pathogenesis of allergic asthma. Here, we have evaluated the anti-inflammatory impact of dimethyl fumarate (DMF) in allergic asthma with more focus on determining its effect on T cell responses in allergic asthma. By utilizing the ovalbumin (OVA)-induced allergic asthma model, we observed that DMF administration reduced the allergic asthma symptoms and IgE levels in the OVA-induced mice model. Histopathological analysis showed that DMF treatment in an OVA-induced animal model eased the inflammation in the nasal and bronchial tissues, with a particular decrease in the infiltration of immune cells. Additionally, RT-qPCR analysis exhibited that treatment of DMF in an OVA-induced model reduced the expression of inflammatory cytokine (IL4, IL13, and IL17) while augmenting anti-inflammatory IL10 and Foxp3 (forkhead box protein 3). Mechanistically, we found that DMF increased the expression of Foxp3 by exacerbating the expression of nuclear factor E2-related factor 2 (Nrf2), and the in-vitro activation of Foxp3+ Tregs leads to an escalated expression of Nrf2. Notably, CD4-specific Nrf2 deletion intensified the allergic asthma symptoms and reduced the in-vitro iTreg differentiation. Meanwhile, DMF failed to exert protective effects on OVA-induced allergic asthma in CD4-specific Nrf2 knock-out mice. Overall, our study illustrates that DMF enhances Nrf2 signaling in T cells to assist the differentiation of Tregs, which could improve the anti-inflammatory immune response in allergic asthma.

Elevated Saliva Pepsin Concentration as a Risk Factor for Asthma in Children with Allergic Rhinitis: A Preliminary Study.

This study aimed to explore whether saliva pepsin concentration (SPC) could be regarded as a risk factor for the occurrence and unfavorable control of asthma in children with allergic rhinitis. A prospective study was conducted on a group of 20 consecutive children newly diagnosed with allergic rhinitis and asthma (referred to as the asthma group). All these children underwent fractional exhaled nitric oxide (FeNO) measurement, lung function tests, and assessment of asthma control using the 7-item Childhood Asthma Control Test (C-ACT) score. Simultaneously, a control group consisting of 20 children with simple allergic rhinitis, matched for baseline characteristics, was included. SPC measurement was performed in the two groups. The SPC value was significantly higher in the asthma group than that in the control group (165.0 ± 82.8 ng/mL vs 68.4 ± 34.5 ng/mL) (P < 0.001). In the asthma group, SPC was independently associated with FeNO, the ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC), and forced expiratory flow at 50% and 75% of FVC (FEF50 and FEF75) (all P < 0.05). The severity of nasal symptoms evaluated by the visual analogue scale (N-VAS) was independently associated with FEF75, the maximal mid-expiratory flow (MMEF), and C-ACT score (P < 0.05). Direct pepsin exposure and uncontrolled nasal symptoms may play crucial roles in the pathogenesis and progression of childhood allergic asthma. The SPC value can be considered as a risk factor for asthma in children with allergic rhinitis.

Heme oxygenase-1 alleviates allergic airway inflammation by suppressing NF-κB-mediated pyroptosis of bronchial epithelial cells.

Allergic asthma development and pathogenesis are influenced by airway epithelial cells in response to allergens. Heme oxygenase-1 (HO-1), an inducible enzyme responsible for the breakdown of heme, has been considered an appealing target for the treatment of chronic inflammatory diseases. Herein, we report that alleviation of allergic airway inflammation by HO-1-mediated suppression of pyroptosis in airway epithelial cells (AECs). Using house dust mite (HDM)-induced asthma models of mice, we found increased gasdermin D (GSDMD) in the airway epithelium. Invivo administration of disulfiram, a specific inhibitor of pore formation by GSDMD, decreased thymic stromal lymphopoietin (TSLP) release, T helper type 2 immune response, alleviated airway inflammation, and reduced airway hyperresponsiveness (AHR). HO-1 induction by hemin administration reversed these phenotypes. Invitro studies revealed that HO-1 restrained GSDMD-mediated pyroptosis and cytokine TSLP release in AECs by binding Nuclear Factor-Kappa B (NF-κB) p65 RHD domain and thus controlling NF-κB-dependent pyroptosis. These data provide new therapeutic indications for purposing HO-1 to counteract inflammation, which contributes to allergic inflammation control.

The study of the role of purified anti-mouse CD193 (CCR3) antibody in allergic rhinitis mouse animal models

The pathogenesis of allergic asthma is similar to that of allergic rhinitis, with inflammation cells producing and releasing inflammatory mediators and cytokines closely related to CCR3.Based on the theory of "one airway, one disease", the use of CCR3 monoclonal antibody may have a similar effect on allergic rhinitis. However, there are few studies on CCR3 monoclonal antibody in allergic rhinitis. Therefore, the aim of this study was to investigate the effective concentration of CCR3 monoclonal antibody, to compare the effects of different methods of administration, and to examine the lung condition of allergic mice to investigate whether antibody treatment protects the lungs. In this study, we constructed a mouse model of allergic rhinitis and intraperitoneally injected different doses of CCR3 monoclonal antibody (5, 10, and 20 uL/mg) to observe its therapeutic effect: observing changes in tissue morphology of nasal mucosa, infiltration of inflammation, and using ELISA to detect changes in relevant inflammatory mediators and cytokines, studying the role of CCR3 mAb in inhibiting CCR3-related actions on the nasal mucosa of allergic rhinitis mice. Furthermore, In addition, the therapeutic effects of intraperitoneal injection (i.p.) and intranasal administration (i.n.) were studied on the basis of effective concentrations.

S100A8/9 modulates perturbation and glycolysis of macrophages in allergic asthma mice.

Allergic asthma is the most prevalent asthma phenotype and is associated with the disorders of immune cells and glycolysis. Macrophages are the most common type of immune cells in the lungs. Calprotectin (S100A8 and S100A9) are two pro-inflammatory molecules that target the Toll-like receptor 4 (TLR4) and are substantially increased in the serum of patients with severe asthma. This study aimed to determine the effects of S100A8/A9 on macrophage polarization and glycolysis associated with allergic asthma. To better understand the roles of S100A8 and S100A9 in the pathogenesis of allergic asthma, we used ovalbumin (OVA)-induced MH-S cells, and OVA-sensitized and challenged mouse models (wild-type male BALB/c mice). Enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, flow cytometry, hematoxylin-eosin staining, and western blotting were performed. The glycolysis inhibitor 3-bromopyruvate (3-BP) was used to observe changes in glycolysis in mice. We found knockdown of S100A8 or S100A9 in OVA-induced MH-S cells inhibited inflammatory cytokines, macrophage polarization biomarker expression, and pyroptosis cell proportion, but increased anti-inflammatory cytokine interleukin (IL)-10 mRNA; also, glycolysis was inhibited, as evidenced by decreased lactate and key enzyme expression; especially, knockdown of S100A8 or S100A9 inhibited the activity of TLR4/myeloid differentiation primary response gene 88 (MyD88)/Nuclear factor kappa-B (NF-κB) signaling pathway. Intervention with lipopolysaccharides (LPS) abolished the beneficial effects of S100A8 and S100A9 knockdown. The observation of OVA-sensitized and challenged mice showed that S100A8 or S100A9 knockdown promoted respiratory function, improved lung injury, and inhibited inflammation; knockdown of S100A8 or S100A9 also suppressed macrophage polarization, glycolysis levels, and activation of the TLR4/MyD88/NF-κB signaling pathway in the lung. Conversely, S100A9 overexpression exacerbated lung injury and inflammation, promoting macrophage polarization and glycolysis, which were antagonized by the glycolysis inhibitor 3-BP. S100A8 and S100A9 play critical roles in allergic asthma pathogenesis by promoting macrophage perturbation and glycolysis through the TLR4/MyD88/NF-κB signaling pathway. Inhibition of S100A8 and S100A9 may be a potential therapeutic strategy for allergic asthma.

The role and molecular mechanisms of alternative splicing of Th2-cytokines IL-4 and IL-5 in atopic bronchial asthma

Bronchial asthma (BA) is a heterogeneous chronic inflammatory disease of the respiratory tract. Allergic asthma is the most common (up to 80% of cases) phenotype developing through Th2-dependent mechanisms involving cytokines: IL-4, IL-5, IL-9 and IL-13. The genes encoding Th2-cytokines have a mosaic structure (encode exons and introns). Therefore, several mature mRNA transcripts and protein isoforms can be derived from a single mRNA precursor through alternative splicing, and they may contribute to BA pathogenesis. Analysis of published studies and databases revealed the existence of alternative mRNA transcripts for IL-4, IL-5, and IL-13. Alternative transcripts of IL-4 and IL-5 carry open reading frames and therefore can encode functional proteins. It was shown that not only alternative mRNA transcripts are exist for IL-4, but alternative protein isoforms, as well. Natural protein isoform IL-4δ2 lacking part encoded by exon-2 was identified. Similarly, alternative mRNA transcript omitting exon-2 (IL-5δ2) was also identified for IL-5. In this review, we summarize current knowledge about identified alternative mRNA transcripts and protein isoforms of Th2-cytokinins, first of all IL-4 and IL-5. We have analyzed biological properties of alternative variants of these cytokines, their possible role in the allergic asthma pathogenesis, and considered their diagnostic and therapeutic potential.

Formononetin ameliorates airway inflammation by suppressing ESR1/NLRP3/Caspase-1 signaling in asthma

Since inhaled glucocorticoids are the first-line treatment for asthma, asthma management becomes extremely difficult when asthma does not react well to glucocorticoids. Formononetin, a bioactive isoflavone and typical phytoestrogen, has been shown to have an anti-inflammatory impact while alleviating epithelial barrier dysfunction, which plays a role in the pathogenesis of allergic illnesses like asthma. However, the biological mechanisms behind this impact are unknown. As a result, we set out to investigate the effects of formononetin on airway inflammation and epithelial barrier repair in house dust mite (HDM)-induced asthmatic mice. We further expanded on formononetin's putative mode of action in reducing airway inflammation by modifying epithelial barrier dysfunction. In the current study, researchers discovered that formononetin significantly lowered total IgE levels in serum and interleukin (IL)-4, IL-6, and IL-17A levels in bronchoalveolar lavage fluid (BALF) in HDM-challenged asthmatic mice. Experiments on cell proliferation, migration, and apoptosis were performed in vitro to determine the effect of formononetin on bronchial epithelial barrier repair. Furthermore, in lipopolysaccharide (LPS)-stimulated 16HBE cells, formononetin increased cell proliferation and migration while preventing apoptosis and lowering the Bax/Bcl-2 ratio. In vitro and in vivo, formononetin significantly inhibited toll-like receptor 4 (TLR4) and estrogen receptor (ESR1)/Nod-like receptor family pyrin domain-containing protein 3 (NLRP3)/Caspase-1 signaling. These findings show that formononetin can reduce airway inflammation in HDM-challenged asthmatic mice by promoting epithelial barrier repair and possibly by inhibiting ESR1/NLRP3/Caspase-1 signaling as the underlying mechanism; formononetin could be a promising alternative treatment for asthma.

Role and Molecular Mechanisms of Alternative Splicing of Th2-Cytokines IL-4 and IL-5 in Atopic Bronchial Asthma.

Bronchial asthma (BA) is a heterogeneous chronic inflammatory disease of the respiratory tract. Allergic (atopic) asthma is the most common (up to 80% of cases) phenotype developing through the Th2-dependent mechanisms involving cytokines: IL-4, IL-5, IL-9, and IL-13. The genes encoding Th2-cytokines have a mosaic structure (encode exons and introns). Therefore, several mature mRNA transcripts and protein isoforms can be derived from a single mRNA precursor through alternative splicing, and they may contribute to BA pathogenesis. Analysis of the published studies and databases revealed existence of the alternative mRNA transcripts for IL-4, IL-5, and IL-13. The alternative transcripts of IL-4 and IL-5 carry open reading frames and therefore can encode functional proteins. It was shown that not only alternative mRNA transcripts exist for IL-4, but alternative protein isoforms, as well. Natural protein isoform (IL-4δ2) lacking the part encoded by exon-2 was identified. Similarly, alternative mRNA transcript with deleted exon-2 (IL-5δ2) was also identified for IL-5. In this review, we summarize current knowledge about the identified alternative mRNA transcripts and protein isoforms of Th2-cytokinins, first of all IL-4 and IL-5. We have analyzed biological properties of the alternative variants of these cytokines, their possible role in the allergic asthma pathogenesis, and considered their diagnostic and therapeutic potential.

IL-22 Is Deleterious along with IL-17 in Allergic Asthma but Is Not Detrimental in the Comorbidity Asthma and Acute Pneumonia.

There is evidence that IL-22 and IL-17 participate in the pathogenesis of allergic asthma. To investigate the role of IL-22, we used IL-22 deficient mice (IL-22 KO) sensitized and challenged with ovalbumin (OVA) and compared with wild type (WT) animals exposed to OVA. IL-22 KO animals exposed to OVA showed a decreased number and frequency of eosinophils, IL-5 and IL-13 in the airways, reduced mucus production and pulmonary inflammation. In addition, IL-22 KO animals exhibited a decreased percentage and number of lung CD11c+CD11b+ cells and increased apoptosis of eosinophils. Th17 cell transfer generated from IL-22 KO to animals previously sensitized and challenged with OVA caused a reduction in eosinophil frequency and number in the airways compared to animals transferred with Th17 cells generated from WT mice. Therefore, IL-22 is deleterious with concomitant secretion of IL-17. Our findings show a pro-inflammatory role for IL-22, confirmed in a model of allergen-free and allergen-specific immunotherapy. Moreover, during the comorbidity asthma and pneumonia that induces neutrophil inflammation, IL-22 was not detrimental. Our results show that targeting IL-22 would negatively affect the survival of eosinophils, reduce the expansion or migration of CD11c+CD11b+ cells, and negatively regulate allergic asthma.

Investigation of miRNAs that are effective in the pathogenesis of asthma

Objectives Asthma is a complex disease characterized by inflammation of the airways, involving epigenetic changes, in which genetic and environmental factors act together. MicroRNAs as candidate biomarkers stand out as target molecules in the diagnosis and treatment of immunological and inflammatory diseases. Our aim of this study is to identify miRNAs that are thought to be effective in the pathogenesis of allergic asthma and to reveal candidate biomarkers associated with the disease. Methods Fifty patients, aged between 18-80 years, who were diagnosed with allergic asthma and 18 healthy volunteers were included in the study. After the collection 2 mL of total blood from volunteers, RNA isolation and cDNA synthesis were performed. For miRNA profile screening, expression analysis was performed by real-time PCR method using miScript miRNA PCR Array. GeneGlobe Data Analysis Center was used to evaluate dysregulated miRNAs. Results In the allergic asthma group, 9 (18%) of the patients were male and 41 (82%) of them were female. In the control group, 7 (38.89%) were male and 11 (61.1%) were female (P:0.073). As a result of the research, the expression levels of miR-142-5p, miR-376c-3p and miR-22-3p were down-regulated, while miR-27b-3p, miR-26b-5p, miR-15b-5p and miR-29c-3p detected as up-regulated. Discussion The results of our study suggest that miR142-5p, miR376c-3p and miR22-3p promote Ubiquitin-mediated proteolysis by inhibiting TGF-β expression through a mechanism involving the p53 signaling pathway. The deregulated miRNAs may be used as a diagnostic and prognostic biomarker in asthma.

Immunometabolic changes in macrophages in response to house dust mite extract

To date, much remains unclear about the pathogenesis of asthma, one of the most common chronic and highly heterogenic diseases of the respiratory system. The lack of specific and highly effective therapy in case of certain asthma subtypes requires the search for new approaches to treatment. One possible approach would be to influence the metabolism and immune functions of myeloid cells. This approach finds its application in the treatment of cancer and other diseases in the pathogenesis of which macrophages play an important role. It was shown that the pathogenesis of allergic asthma in response to one of the most common allergens, house dust mite, is due to a metabolic TNF-mediated reprogramming of alveolar macrophages. This suggests that influencing the process of TNF production or metabolic adaptations with specific blockers may also lead to a reduction in the symptoms of the course of the disease as a whole. In this work, we experimentally tested whether the previously obtained phenotype that occurs in macrophages in response to HDM cultured in DMEM is preserved if cells are cultured under more physiologically relevant conditions: in a medium closely related in composition to blood plasma. We also analyzed open databases of alveolar macrophages sequencing obtained from patients with asthma or from the lungs of mice in an HDM-induced asthma model in order to correlate specific immunometabolic changes. It was found that macrophages cultured under conditions close to physiological, simultaneously increase the rates of respiration and glycolysis, and also produce TNF in response to HDM. The observed phenotype is consistent with transcriptomic analyzes performed on human and mouse samples, which revealed an increase in the expression of genes related to glycolysis, oxidative phosphorylation, and the TNF signaling pathway. Thus, the data confirm the relevance of the phenotype obtained in vitro to the changes occurring in the in vivo system. However, functional verification at the level of metabolites, proteins and changes in metabolic activity is also required. In addition, it remains to be established how the blocking of individual metabolic pathways affects the features of the functional macrophage phenotype that occurs in response to HDM, and whether this effect can alleviate asthma symptoms.

NOX2-Deficient Pulmonary Neutrophils and Macrophages Have Lower PD-L1 Expression and May Aggravate Allergic Lung Inflammation through Affecting ILC Populations

Abstract Redox balance plays an important role in the pathogenesis of allergic asthma. We previously reported that NADPH oxidase 2 (NOX2)-derived ROS may modulate tissue inflammation through affecting neutrophil programmed cell death 1 ligand 1 (PD-L1) expression. To reveal the role of NOX2 in regulating PD-L1 expressions on pulmonary neutrophils and macrophages and in ILC differentiation, we established an allergic asthma model using NOX2-deficient (Cybb−/−)mice stimulated with the Dermatophagoides pteronyssinus(Der p) extract along with LPS. We first found that NOX2 deficiency led to increased group 2 innate lymphoid cell (ILC2) in Der p extract induced lung inflammation. The cell numbers of neutrophil, eosinophil and alveolar macrophage (AM) also increased in the stimulated Cybb−/−mice when compared with WT mice. The AM in Cybb−/−mice expressed higher levels of CD11b and the M2 marker CD163 and produced more TNF-α. Moreover, the Cybb−/−neutrophils and AMs had low PD-L1 expressions while ILC2s had significant levels of programmed cell death 1 (PD-1) expression in the inflammatory lungs. Altogether, these results indicated that NOX2 deficiency may lead to downregulation of PD-L1 expression on neutrophils and AMs while eliciting the M2 phenotype and inducing higher amounts of pro-inflammatory cytokine production. Our results suggested that the lowered PDL1 on NOX2-deficient neutrophils and AMs may aggravate allergic Inflammation through affecting ILC populations in the lung.

IL-17A deficiency alleviates PM-induced allergic asthma by suppressing Th17 cell secretion cytokines and mucus overproduction

Abstract Particulate matter (PM) aggravates airway and lung inflammatory response in allergic asthma by directly inducing Th17 cells to secrete Th17 cell-associated inflammatory factors and chemokines. IL-17A is a key Th17 cell secretion pro-inflammatory cytokine. In this study, we investigated the role of IL-17A in PM-induced allergic asthma in mice. 7–8 weeks old wild type (WT) mice, and similarly IL-17A knockout (KO) mice, were divided into four experimental groups (healthy control, PM only, OVA only, OVA+PM treatment groups) and treated accordingly. Inflammatory cell and eosinophil infiltration were increased in the PM-induced WT mice compared to WT healthy control, but were decreased in KO mice compared to PM-induced WT mice. Among toll-like receptors (TLRs) that play an important role in innate immune response, TLR2/4/7 expression was significantly increased in PM-induced WT mice, but was reduced in KO mice. Furthermore, we observed decrease in mRNA expression of IL-13, IL-17A, IL-22, and TGF-β among cytokines of Th2 and Th17 cells in KO mice. PM-induced WT mice facilitated the overt histopathological symptoms of allergic asthma such as mucus overproduction and goblet cell hyperplasia while KO mice showed mitigated such responses compared to PM-induced allergic asthma WT mice. These results prove that IL-17A plays a key role in pathogenesis of PM-induced allergic asthma. This research was funded by the Ministry of Education. This research was funded by the Ministry of Education

Trajectory of neutrophilic responses in a mouse model of pollutant-aggravated allergic asthma

Experimental studies suggest that neutrophils could contribute to allergic asthma pathogenesis, that is mainly driven by type 2 immunity. Inhalation of diesel exhaust particles (DEP) is implicated in both exacerbation and development of asthma. Since exposure to DEP is associated with a neutrophilic component, we aimed to investigate how exposure to the combination of allergens and DEP modulates neutrophilic responses. Human bronchial epithelial cells (HBEC) were exposed to house dust mite (HDM), DEP or HDM + DEP in vitro to determine the expression of neutrophil-recruiting chemokines. Female (C57BL/6 J) mice were intranasally instilled with saline, DEP, HDM or combined HDM + DEP for 3 weeks (subacute) or 6 weeks (chronic). The neutrophilic responses were determined in lung tissue and bronchoalveolar lavage fluid (BALF). Simultaneous exposure to HDM + DEP resulted in increased CXCL1 and CXCL8 mRNA expression by HBEC in vitro. In mice, subacute exposure to HDM + DEP induced a strong mixed eosinophilic/neutrophilic inflammation in BALF and lung and was associated with higher expression of neutrophil-attracting chemokines and NET formation compared to the sole exposures. After chronic HDM + DEP exposure, a similar neutrophilic response was observed, however the NET formation was less pronounced. Interestingly, the increase of BALF eosinophils was also significantly attenuated after chronic HDM + DEP exposure compared to the subacute exposure. Subacute and chronic HDM + DEP exposure induced goblet cell hyperplasia and airway hyperresponsiveness. Our data suggest a role for neutrophils and NETs in pollutant-aggravated eosinophilic allergic asthma. Moreover, subacute exposure to HDM + DEP induces a mixed eosinophilic/neutrophilic response whereas upon chronic HDM + DEP exposure there is a shift in inflammatory response with a more prominent neutrophilic component.

Transcriptomic analysis identified SLC40A1 as a key iron metabolism-related gene in airway macrophages in childhood allergic asthma.

Introduction: Asthma is the most common chronic condition in children, with allergic asthma being the most common phenotype, accounting for approximately 80% of cases. Growing evidence suggests that disruption of iron homeostasis and iron regulatory molecules may be associated with childhood allergic asthma. However, the underlying molecular mechanism remains unclear. Methods: Three childhood asthma gene expression datasets were analyzed to detect aberrant expression profiles of iron metabolism-related genes in the airways of children with allergic asthma. Common iron metabolism-related differentially expressed genes (DEGs) across the three datasets were identified and were subjected to functional enrichment analysis. Possible correlations between key iron metabolism-related DEGs and type 2 airway inflammatory genes were investigated. Single-cell transcriptome analysis further identified major airway cell subpopulations driving key gene expression. Key iron metabolism-related gene SLC40A1 was validated in bronchoalveolar lavage (BAL) cells from childhood asthmatics with control individuals by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunofluorescence. The intracellular iron content in BAL cells was assessed by Perls iron staining and the iron levels in BAL supernatant was measured by iron assay to assess airway iron metabolism status in childhood asthmatics. Results: Five common iron metabolism-related DEGs were identified, which were functionally related to iron homeostasis. Among these genes, downregulated SLC40A1 was strongly correlated with type 2 airway inflammatory markers and the gene signature of SLC40A1 could potentially be used to determine type 2-high and type 2-low subsets in childhood allergic asthmatics. Further single-cell transcriptomic analysis identified airway macrophages driving SLC40A1 expression. Immunofluorescence staining revealed colocalization of FPN (encoded by SLC40A1) and macrophage marker CD68. Down-regulation of SLC40A1 (FPN) was validated by qRT-PCR and immunofluorescence analysis. Results further indicated reduced iron levels in the BAL fluid, but increased iron accumulation in BAL cells in childhood allergic asthma patients. Furthermore, decreased expression of SLC40A1 was closely correlated with reduced iron levels in the airways of children with allergic asthma. Discussion: Overall, these findings reveal the potential role of the iron metabolism-related gene SLC40A1 in the pathogenesis of childhood allergic asthma.

CD200Fc limits dendritic cell and B-cell activation during chronic allergen exposures.

Allergic asthma is a chronic inflammatory disease characterized by Th2, conventional dendritic cell, and B-cell activation. In addition to excessive inflammation, asthma pathogenesis includes dysregulation of anti-inflammatory pathways, such as the CD200/CD200R pathway. Thus, we investigated whether a CD200R agonist, CD200Fc, could disrupt the inflammatory cascade in chronic allergic asthma pathogenesis using a mice model of experimental asthma. Mice were exposed to house dust mites for 5 wk, and CD200Fc treatment was initiated after chronic inflammation was established (starting on week 4). We demonstrate that chronic house dust mite exposure altered CD200 and CD200R expression on lung immune cell populations, including upregulation of CD200 on alveolar macrophages and reduced expression of CD200 on conventional dendritic cells. CD200Fc treatment does not change bronchoalveolar cellular infiltration, but it attenuates B-cell activation and skews the circulating immunoglobulin profile toward IgG2a. This is accompanied by reduced activation of conventional dendritic cells, including lower expression of CD40, especially on conventional dendritic cell subset 2 CD200R+. Furthermore, we confirm that CD200Fc can directly modulate conventional dendritic cell activation in vitro using bone marrow-derived dendritic cells. Thus, the CD200/CD200R pathway is dysregulated during chronic asthma pathogenesis, and the CD200R agonist modulates B-cell and dendritic cell activation but, in our chronic model, is not sufficient to alter inflammation measured in bronchoalveolar lavage.

Research of the Expression of IL-13 Receptors and IL-13R Genes in the Bronch of Rats with Ovalbumin-Induced Bronchial Asthma

This article presents the results of studies of the levels of expression of the IL13R gene and the levels of expression of the molecular IL13R in the bronchi of control rats and rats with ovalbumin-induced asthma. The choice of these receptors is due to the great importance of these structures in the pathogenesis of allergic bronchial asthma. Biological materials of 64 Wistar rats were studied using real-time PCR and immunohistochemical methods. As a result of the studies, it was found that under conditions of asthma development in the tissues of the bronchi of rats, a pronounced expression of the IL13R genes, a significant expression of the molecular receptor for interleukin-13, occurs. In bronchi with an intramural ganglion (bifurcation zone), the level of IL13R gene expression and the level of expression of the IL13R molecular receptor were significantly higher than in tracheal samples without ganglia. Sodium cromoglycate, administered to rats 5 hours after the last inhalation of ovalbumin, led to a decrease in the mRNA content in the bronchi of animals compared to animals that did not receive mast cell stabilizer treatment.