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Introduction: Allergic asthma has been linked to the activation of mast cells (MCs) by the neuropeptide substance P (SP), but the mechanism underlying this neuroimmune interaction is unknown. Substance P produced from cutaneous nociceptors activates MCs via Mas-related G-protein-coupled receptor B2 (MrgprB2) to enhance type 2 immune response in experimental atopic dermatitis in mice. We recently showed that the adapter protein β-arrestin2 (β-arr2) contributes to MrgprB2-mediated MC chemotaxis. The goals of this study were to determine if MrgprB2 facilitates neuroimmune interaction in IgE (FcεRI)-mediated allergic airway inflammation (AAI) and to assess if this response is modulated by β-arr2. Methods: Wild-type (WT), MrgprB2−/− mice and mice with MC-specific deletion of β-arr2 (Cpa3Cre+/β-arr2fl/fl) were passively sensitized with anti-TNP-IgE and challenged with antigen. The generation of SP and MC recruitment in the lung were determined by immunofluorescence and toluidine blue staining, respectively. The transcripts for Tac1, MrgprB2, TNF-α, and Th2 cytokines in lung tissue were assessed by RT-PCR, and the release of selected cytokines in bronchoalveolar lavage (BAL) was determined by ELISA. Eosinophil and neutrophil recruitment in lung tissue and BAL were determined by immunofluorescence staining and flow cytometry, respectively. Goblet cell hyperplasia was determined by periodic acid–Schiff staining. Results: Following IgE sensitization and antigen challenge in WT mice, SP generation, and MC recruitment, transcripts for Tac1, MrgprB2, TNF-α, and Th2 cytokine were upregulated when compared to the control challenge. TNF-α, Th2 cytokine production, eosinophil/neutrophil recruitment, and goblet cell hyperplasia were also increased. These responses were significantly reduced in MrgprB2−/− and Cpa3Cre+/β-arr2fl/fl mice. Discussion: The data presented herein suggest that SP-mediated MrgprB2 activation contributes to AAI and goblet cell hyperplasia in mice. Furthermore, these responses are modulated by β-arr2, which promotes MC recruitment to facilitate their activation through FcεRI. [ABSTRACT FROM AUTHOR]

Introduction: Allergic asthma is prevalent in children, with Dermatophagoides farinae as a common indoor allergen. Current treatments for allergic airway inflammation are limited and carry risks. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) show promise as a cell-free therapeutic approach. However, the use of engineered MSC-EVs for D. farinae-induced allergic airway epithelial cell inflammation remains unexplored. Methods: We generated miR-146a-5p-engineered EVs from human umbilical cord mesenchymal stem cells (hucMSCs) and established D. farinae-induced mouse and human bronchial epithelial cell allergic models. Levels of IL-1b, IL-18, IL-4, IL-5, IL-6, IL-10, IL-33, TNF-α and IgE were detected using ELISA. The relative TRAF6 and IRAK1 mRNA expression was quantified using qPCR assay and the NLRP3, NF-κB, IRAK1 and TRAF6 protein expression was determined using Western blotting. The regulatory effect of IRAK1 and TRAF6 by miR-146a-5p was examined using a dual luciferase reporter assay, and the nuclear translocation of NF-κB p65 into 16-HBE cells was evaluated using immunofluorescence assay. Results: Treatment with hucMSC-EVs effectively reduced allergic inflammation, while miR-146a-5p engineered hucMSC-EVs showed greater efficacy. The enhanced efficacy in alleviating allergic airway inflammation was attributed to the downregulation of IRAK1 and TRAF6 expression, facilitated by miR-146a-5p. This downregulation subsequently led to a decrease in NF-κB nuclear translocation, which in turn resulted in reduced activation of the NLRP3 inflammasome and diminished production of inflammatory cytokines, including IL-6, TNF-α, IL-1β and IL-18. Conclusion: Our study underscores the potential of miR-146a-5p engineered hucMSC-EVs as a cell-free therapeutic strategy for D. farinae-induced allergic airway inflammation, offering a promising avenue for boosting antiinflammatory responses. [ABSTRACT FROM AUTHOR]

Background: The rise in asthma has been linked to different environmental and lifestyle factors including dietary habits. Whether dietary salt contributes to asthma incidence, remains controversial. We aimed to investigate the impact of higher salt intake on asthma incidence in humans and to evaluate underlying mechanisms using mouse models. Methods: Epidemiological research was conducted using the UK Biobank Resource. Data were obtained from 42,976 participants with a history of allergies. 24‐h sodium excretion was estimated from spot urine, and its association with asthma incidence was assessed by Cox regression, adjusting for relevant covariates. For mechanistic studies, a mouse model of mite‐induced allergic airway inflammation (AAI) fed with high‐salt diet (HSD) or normal‐salt chow was used to characterize disease development. The microbiome of lung and feces (as proxy for gut) was analyzed via 16S rRNA gene based metabarcoding approach. Results: In humans, urinary sodium excretion was directly associated with asthma incidence among females but not among males. HSD‐fed female mice displayed an aggravated AAI characterized by increased levels of total IgE, a TH2‐TH17‐biased inflammatory cell infiltration accompanied by upregulation of osmosensitive stress genes. HSD induced distinct changes in serum short chain fatty acids and in both gut and lung microbiome, with a lower Bacteroidetes to Firmicutes ratio and decreased Lactobacillus relative abundance in the gut, and enriched members of Gammaproteobacteria in the lung. Conclusions: High dietary salt consumption correlates with asthma incidence in female adults with a history of allergies. Female mice revealed HSD‐induced T‐cell lung profiles accompanied by alterations of gut and lung microbiome. [ABSTRACT FROM AUTHOR]

Background: Allergen-specific immunotherapy (AIT) is able to restore immune tolerance to allergens in allergic patients. However, some patients do not or only poorly respond to current treatment protocols. Therefore, there is a need for deeper mechanistic insights and further improvement of treatment strategies. The relevance of the aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor, has been investigated in several inflammatory diseases, including allergic asthma. However, its potential role in AIT still needs to be addressed. Methods: Amurinemodel of AIT in ovalbumin-induced allergic airway inflammation was performed in AhR-deficient (AhR-/-) and wild-type mice. Furthermore, AIT was combined with the application of the high-affinity AhR agonist 10-chloro-7Hbenzimidazo[2,1-a]benzo[de]iso-quinolin-7-one (10-Cl-BBQ) as an adjuvant to investigate the effects of AhR activation on therapeutic outcome. Results: Although AhR-/- mice suffer stronger allergic responses than wild-type mice, experimental AIT is comparably effective in both. Nevertheless, combining AIT with the administration of 10-Cl-BBQ improved therapeutic effects by an AhRdependent mechanism, resulting in decreased cell counts in the bronchoalveolar fluid, decreased pulmonary Th2 and Th17 cell levels, and lower sIgE levels. Conclusion: This study demonstrates that the success of AIT is not dependent on the AhR. However, targeting the AhR during AIT can help to dampen inflammation and improve tolerogenic vaccination. Therefore, AhR ligands might represent promising candidates as immunomodulators to enhance the efficacy of AIT. [ABSTRACT FROM AUTHOR]

Toll-like receptor 2 (TLR2) and galectin-3 (Gal-3) are involved in the pathological process of asthma, but the underlying mechanism is not fully understood. We hypothesized that TLR2 pathway may regulate expression of Gal-3 in allergic airway inflammation. Wild-type (WT) and TLR2−/− mice were sensitized on day 0 and challenged with ovalbumin (OVA) on days 14–21 to establish a model of allergic airway inflammation, and were treated with a specific ERK inhibitor U0126. Histological changes in the lungs were analyzed by hematoxylin-eosin (HE) and Periodic Acid-Schiff (PAS) staining; cytokines and anti-OVA immunoglobulin E (IgE) were tested by ELISA; and related protein expression in lung tissues was measured by western blot. We found that the expression levels of TLR2 and Gal-3 markedly increased concomitantly with airway inflammation after OVA induction, while TLR2 deficiency significantly alleviated airway inflammation and reduced Gal-3 expression. Moreover, the expression levels of phosphorylated mitogen-activated protein kinases (p-MAPKs) were significantly elevated in OVA-challenged WT mice, while TLR2 deficiency only significantly decreased phosphorylated extracellular signal-regulated kinase (p-ERK) levels. Furthermore, we found that U0126 treatment significantly alleviated allergic airway inflammation and decreased Gal-3 levels in OVA-challenged WT mice, but had no further effect in OVA-challenged TLR2−/− mice. These above results suggested that TLR2 is an upstream signal molecule of ERK. We further demonstrated that TLR2 regulates Gal-3 expression through the ERK pathway in LTA-stimulated macrophages in vitro. Our findings showed that the TLR2-ERK signaling pathway regulates Gal-3 expression in a murine model of allergic airway inflammation. • TLR2 and MAPKs signal pathways were activated concomitantly with increased Galectin-3 expression in OVA-induced allergic mice. • TLR2 deficiency significantly reduced airway inflammation, ERK phosphorylation and -Galectin-3 expression in allergic mice. • TLR2 signaling regulated airway inflammation and Galectin-3 expression through ERK pathway in allergic mice. [ABSTRACT FROM AUTHOR]

Group 2 innate lymphoid cells (ILC2s) play critical roles in driving the pathogenesis of allergic airway inflammation. The mechanisms underlying the regulation of ILC2s remain to be fully understood. Here, we identified neuropilin‐1 (NRP1) as a surface marker of ILC2s in response to IL‐33 stimulation. NRP1 was abundantly expressed in ILC2s from lung under steady state, which was significantly reduced upon IL‐33 stimulation. ILC2s with high expression of NRP1 (NRP1high) displayed lower response to IL‐33, as compared with NRP1low ILC2s. Transcriptional profiling and flow cytometric analysis showed that downregulation of AKT–mTOR signalling participated in the diminished functionality of NRP1high ILC2s. These observations revealed a potential role of NRP1 in ILC2s responses under allergic inflammatory condition. [ABSTRACT FROM AUTHOR]

IntroductionAllergic asthma has been linked to the activation of mast cells (MCs) by the neuropeptide substance P (SP), but the mechanism underlying this neuroimmune interaction is unknown. Substance P produced from cutaneous nociceptors activates MCs via Mas-related G-protein-coupled receptor B2 (MrgprB2) to enhance type 2 immune response in experimental atopic dermatitis in mice. We recently showed that the adapter protein β-arrestin2 (β-arr2) contributes to MrgprB2-mediated MC chemotaxis. The goals of this study were to determine if MrgprB2 facilitates neuroimmune interaction in IgE (FcεRI)-mediated allergic airway inflammation (AAI) and to assess if this response is modulated by β-arr2.MethodsWild-type (WT), MrgprB2−/− mice and mice with MC-specific deletion of β-arr2 (Cpa3Cre+/β-arr2fl/fl) were passively sensitized with anti-TNP-IgE and challenged with antigen. The generation of SP and MC recruitment in the lung were determined by immunofluorescence and toluidine blue staining, respectively. The transcripts for Tac1, MrgprB2, TNF-α, and Th2 cytokines in lung tissue were assessed by RT-PCR, and the release of selected cytokines in bronchoalveolar lavage (BAL) was determined by ELISA. Eosinophil and neutrophil recruitment in lung tissue and BAL were determined by immunofluorescence staining and flow cytometry, respectively. Goblet cell hyperplasia was determined by periodic acid–Schiff staining.ResultsFollowing IgE sensitization and antigen challenge in WT mice, SP generation, and MC recruitment, transcripts for Tac1, MrgprB2, TNF-α, and Th2 cytokine were upregulated when compared to the control challenge. TNF-α, Th2 cytokine production, eosinophil/neutrophil recruitment, and goblet cell hyperplasia were also increased. These responses were significantly reduced in MrgprB2−/− and Cpa3Cre+/β-arr2fl/fl mice.DiscussionThe data presented herein suggest that SP-mediated MrgprB2 activation contributes to AAI and goblet cell hyperplasia in mice. Furthermore, these responses are modulated by β-arr2, which promotes MC recruitment to facilitate their activation through FcεRI.

Introduction: Allergic asthma has been mainly attributed to T helper type 2 (Th2) and proinflammatory responses but many cellular processes remain elusive. There is increasing evidence for distinct roles for macrophage and dendritic cell (DC) subsets in allergic airway inflammation (AAI). At the same time, there are various mouse models for allergic asthma that have been of utmost importance in identifying key inflammatory pathways in AAI but that differ in the allergen and/ or route of sensitization. It is unclear whether and how the accumulation and activation of specialized macrophage and DC subsets depend on the experimental model chosen for analyses. Methods: In our study, we employed high-parameter spectral flow cytometry to comprehensively assess the accumulation and phenotypic alterations of different macrophage- and DC-subsets in the lung in an OVA- and an HDM-mediated mouse model of AAI. Results: We observed subset-specific as well as model-specific characteristics with respect to cell numbers and functional marker expression. Generally, alveolar as opposed to interstitial macrophages showed increased MHCII surface expression in AAI. Between the models, we observed significantly increased numbers of alveolar macrophages, CD103+ DC and CD11b+ DC in HDM-mediated AAI, concurrent with significantly increased airway interleukin-4 but decreased total serum IgE levels. Further, increased expression of CD80 and CD86 on DC was exclusively detected in HDM-mediated AAI. Discussion: Our study demonstrates a model-specific involvement of macrophage and DC subsets in AAI. It further highlights spectral flow cytometry as a valuable tool for their comprehensive analysis under inflammatory conditions in the lung. [ABSTRACT FROM AUTHOR]

Group 2 innate lymphoid cells (ILC2s) are a type of innate immune cells that produce a large amount of IL‐5 and IL‐13 and two cytokines that are crucial for various processes such as allergic airway inflammation, tissue repair and tissue homeostasis. It is known that damaged epithelial‐derived alarmins, such as IL‐33, IL‐25 and thymic stromal lymphopoietin (TSLP), are the predominant ILC2 activators that mediate the production of type 2 cytokines. In recent years, abundant studies have found that many factors can regulate ILC2 development and function. Hormones synthesized by the body's endocrine glands or cells play an important role in immune response. Notably, ILC2s express hormone receptors and their proliferation and function can be modulated by multiple hormones during allergic airway inflammation. Here, we summarize the effects of multiple hormones on ILC2‐driven allergic airway inflammation and discuss the underlying mechanisms and potential therapeutic significance. [ABSTRACT FROM AUTHOR]

Background: Inflammatory responses, including airway inflammation, hyper-responsiveness, mucus hyper-secretion, prostaglandins and Th2 cytokines infiltration in the airway submucosa, frequently occur in allergic respiratory disorders. This study sought to investigate the effects of the hydro-ethanolic extract of Scoparia dulcis (SDE) on allergic airway inflammation, airway hyper-responsiveness, goblet cell hyperplasia, mucus hypersecretion, Th2 cytokines and prostaglandin (PG)-D2 using murine asthma models. Methods: Allergic asthma was induced in healthy guinea-pigs, and mice, by exposing them to ovalbumin (OVA) sensitization and challenge, and treatment with either 2 ml/kg normal saline, 10 mg/kg salbutamol, 10 mg/kg prednisolone, 50, 100, or 250 mg/kg of SDE per os. The percentage protection against pre-convulsive dyspnoea after methacholine challenge in OVA-induced asthmatic guinea-pigs was determined for each treatment regime, and histopathological examinations thereafter conducted on the excised lungs. Periodic acid-Schiff staining was also performed to identify goblet cell hyperplasia and mucus hypersecretion in these lung tissues. Lung tissue homogenates and serum from OVA-induced asthmatic mice were also assayed for PGD2, interleukins (IL)-5 and -13 levels using monoclonal antibody-based mouse ELISA kits. Results: SDE treatments prolonged the time taken for pre-convulsive dyspnoea to occur after methacholine challenge in OVA-induced asthmatic guinea-pigs; indicative of a positive activity against airway hyper-responsiveness. Histopathological studies also showed that SDE significantly inhibited (p ≤ 0.05) pulmonary infiltration of leukocytes, inflammatory cell accumulation, airway smooth muscle thickening and goblet cell hyperplasia. Serum and lung tissue concentrations of PGD2, IL-5 and IL-13, significantly elevated (p ≤ 0.001) following allergic asthma induction in mice, were significantly reduced (p ≤ 0.01) back to within normal levels after SDE treatments. Conclusion: The plant extract exhibited anti-asthmatic and anti-inflammatory properties, as it reduced the severity of allergic inflammation and hyper-reactivity, as well as PGD2 and Th2 cytokines infiltration in the airway; and these effects could be exploited for future management of asthma.

Polygonatum odoratum is widely recognized to conribute to various health benefits, primarily attributed to its polysaccharide (POP). Polysaccharides are not directly and readily absorbed by the gastrointestinal system, but can interact with the gut microbes. This study aims to clarify the mechanism of POP in mitigating and preventing OVA-induced allergic airway inflammation via the gut-lung axis. The results showed that POP improved the symptoms associated with allergic respiratory responses, and the efficacy of POP was impeded due to the disruption of gut microbiota caused by antibiotics. The POP altered gut microbiota effectively alleviated the type 2 inflammation, reduced the number of ILC2s in the lung and gut, and inhibited the movement of intestinal ILC2s towards the lung. Clostridia UCG-014 and Rikenellaceae RC9 were figured out as pathogenic bacteria inhibited by POP. This study provides a reference for therapeutic application of POP in managing allergic airway inflammation via the gut-lung axis.

BackgroundAllergen-specific immunotherapy (AIT) is able to restore immune tolerance to allergens in allergic patients. However, some patients do not or only poorly respond to current treatment protocols. Therefore, there is a need for deeper mechanistic insights and further improvement of treatment strategies. The relevance of the aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor, has been investigated in several inflammatory diseases, including allergic asthma. However, its potential role in AIT still needs to be addressed.MethodsA murine model of AIT in ovalbumin-induced allergic airway inflammation was performed in AhR-deficient (AhR-/-) and wild-type mice. Furthermore, AIT was combined with the application of the high-affinity AhR agonist 10-chloro-7H-benzimidazo[2,1-a]benzo[de]iso-quinolin-7-one (10-Cl-BBQ) as an adjuvant to investigate the effects of AhR activation on therapeutic outcome.ResultsAlthough AhR-/- mice suffer stronger allergic responses than wild-type mice, experimental AIT is comparably effective in both. Nevertheless, combining AIT with the administration of 10-Cl-BBQ improved therapeutic effects by an AhR-dependent mechanism, resulting in decreased cell counts in the bronchoalveolar fluid, decreased pulmonary Th2 and Th17 cell levels, and lower sIgE levels.ConclusionThis study demonstrates that the success of AIT is not dependent on the AhR. However, targeting the AhR during AIT can help to dampen inflammation and improve tolerogenic vaccination. Therefore, AhR ligands might represent promising candidates as immunomodulators to enhance the efficacy of AIT.

Abstract Backgrounds Allergic airway inflammation is prevalent worldwide and imposes a considerable burden on both society and affected individuals. This study aimed to investigate the therapeutic advantages of mesenchymal stem cells (MSCs) overexpressed interleukin-10 (IL-10) for the treatment of allergic airway inflammation, as both IL-10 and MSCs possess immunosuppressive properties. Methods Induced pluripotent stem cell (iPSC)-derived MSCs were engineered to overexpress IL-10 via lentiviral transfection (designated as IL-10-MSCs). MSCs and IL-10-MSCs were administered intravenously to mice with allergic inflammation induced by ovalbumin (OVA), and the features of allergic inflammation including inflammatory cell infiltration, Th cells in the lungs, and T helper 2 cell (Th2) cytokine levels in bronchoalveolar lavage fluid (BALF) were examined. MSCs and IL-10-MSCs were co-cultured with CD4+ T cells from patients with allergic rhinitis (AR), and the levels of Th2 cells and corresponding type 2 cytokines were studied. RNA-sequence was performed to further investigate the potential effects of MSCs and IL-10-MSCs on CD4+ T cells. Results Stable IL-10-MSCs were established and characterised by high IL-10 expression. IL-10-MSCs significantly reduced inflammatory cell infiltration and epithelial goblet cell numbers in the lung tissues of mice with allergic airway inflammation. Inflammatory cell and cytokine levels in BALF also decreased after the administration of IL-10-MSCs. Moreover, IL-10-MSCs showed a stronger capacity to inhibit the levels of Th2 after co-cultured with CD4+ T cells from patients with AR. Furthermore, we elucidated lower levels of IL-5 and IL-13 in IL-10-MSCs treated CD4+ T cells, and blockade of IL-10 significantly reversed the inhibitory effects of IL-10-MSCs. We also reported the mRNA profiles of CD4+ T cells treated with IL-10-MSCs and MSCs, in which IL-10 played an important role. Conclusion IL-10-MSCs showed positive effects in the treatment of allergic airway inflammation, providing solid support for the use of genetically engineered MSCs as a potential novel therapy for allergic airway inflammation.

Backgrounds: Allergic airway inflammation is prevalent worldwide and imposes a considerable burden on both society and affected individuals. This study aimed to investigate the therapeutic advantages of mesenchymal stem cells (MSCs) overexpressed interleukin-10 (IL-10) for the treatment of allergic airway inflammation, as both IL-10 and MSCs possess immunosuppressive properties. Methods: Induced pluripotent stem cell (iPSC)-derived MSCs were engineered to overexpress IL-10 via lentiviral transfection (designated as IL-10-MSCs). MSCs and IL-10-MSCs were administered intravenously to mice with allergic inflammation induced by ovalbumin (OVA), and the features of allergic inflammation including inflammatory cell infiltration, Th cells in the lungs, and T helper 2 cell (Th2) cytokine levels in bronchoalveolar lavage fluid (BALF) were examined. MSCs and IL-10-MSCs were co-cultured with CD4+ T cells from patients with allergic rhinitis (AR), and the levels of Th2 cells and corresponding type 2 cytokines were studied. RNA-sequence was performed to further investigate the potential effects of MSCs and IL-10-MSCs on CD4+ T cells. Results: Stable IL-10-MSCs were established and characterised by high IL-10 expression. IL-10-MSCs significantly reduced inflammatory cell infiltration and epithelial goblet cell numbers in the lung tissues of mice with allergic airway inflammation. Inflammatory cell and cytokine levels in BALF also decreased after the administration of IL-10-MSCs. Moreover, IL-10-MSCs showed a stronger capacity to inhibit the levels of Th2 after co-cultured with CD4+ T cells from patients with AR. Furthermore, we elucidated lower levels of IL-5 and IL-13 in IL-10-MSCs treated CD4+ T cells, and blockade of IL-10 significantly reversed the inhibitory effects of IL-10-MSCs. We also reported the mRNA profiles of CD4+ T cells treated with IL-10-MSCs and MSCs, in which IL-10 played an important role. Conclusion: IL-10-MSCs showed positive effects in the treatment of allergic airway inflammation, providing solid support for the use of genetically engineered MSCs as a potential novel therapy for allergic airway inflammation. [ABSTRACT FROM AUTHOR]

Asthma demonstrates a strong circadian rhythm with disrupted molecular clock. Melatonin which can directly regulate circadian rhythm has been reported to alleviate asthma, but whether this effect is related to its regulation on circadian clock has not yet been known. Here, female C57BL/6 mice were challenged with ovalbumin (OVA) to establish allergic airway inflammation, and were treated with melatonin or Luzindole to investigate whether the expressions of circadian clock proteins were changed in response to OVA and were affected by exogenous/endogenous melatonin. Airway inflammation, mucus secretion, protein expressions of circadian proteins (Bmal1, Per1, Clock, Timeless, Cry1 and Cry2), melatonin biosynthetase (ASMT, AANAT) and melatonin receptor (Mel-1A/B–R) were analyzed accordingly. The results showed that in the successfully established allergic airway inflammation model, inflammatory cells infiltration, expressions of circadian clock proteins in the lung tissues of OVA-challenged mice were all notably up-regulated as compared to that of the vehicle mice. Meanwhile, the protein expression of ASMT and the level of melatonin in the lung tissues were reduced in allergic mice, while the expression of melatonin receptor Mel-1A/B–R was markedly increased. After addition of exogenous melatonin, the OVA-induced airway inflammation was pronouncedly ameliorated, while simultaneously the OVA-induced expressions of Per1 and Clock were further increased. However, a melatonin receptor antagonist Luzindole further augmented the OVA-induced airway inflammation, accompanied with remarkably decreased expressions of Per1, Bmal1, Cry1 and Cry2 but notably increased expression of Timeless. Collectively, our results demonstrated that the expression of circadian clock proteins was increased in the lungs during allergic airway inflammation, and Per1 was a clock protein that can be regulated by both exogenous and endogenous melatonin, suggesting Per1 may be an important potential circadian clock target for melatonin as a negative regulatory factor against Th2-type airway inflammation.

IntroductionAllergic asthma has been mainly attributed to T helper type 2 (Th2) and proinflammatory responses but many cellular processes remain elusive. There is increasing evidence for distinct roles for macrophage and dendritic cell (DC) subsets in allergic airway inflammation (AAI). At the same time, there are various mouse models for allergic asthma that have been of utmost importance in identifying key inflammatory pathways in AAI but that differ in the allergen and/or route of sensitization. It is unclear whether and how the accumulation and activation of specialized macrophage and DC subsets depend on the experimental model chosen for analyses.MethodsIn our study, we employed high-parameter spectral flow cytometry to comprehensively assess the accumulation and phenotypic alterations of different macrophage- and DC-subsets in the lung in an OVA- and an HDM-mediated mouse model of AAI.ResultsWe observed subset-specific as well as model-specific characteristics with respect to cell numbers and functional marker expression. Generally, alveolar as opposed to interstitial macrophages showed increased MHCII surface expression in AAI. Between the models, we observed significantly increased numbers of alveolar macrophages, CD103+ DC and CD11b+ DC in HDM-mediated AAI, concurrent with significantly increased airway interleukin-4 but decreased total serum IgE levels. Further, increased expression of CD80 and CD86 on DC was exclusively detected in HDM-mediated AAI.DiscussionOur study demonstrates a model-specific involvement of macrophage and DC subsets in AAI. It further highlights spectral flow cytometry as a valuable tool for their comprehensive analysis under inflammatory conditions in the lung.

Abstract Background E. coli O83 (Colinfant Newborn) is a Gram-negative (G-) probiotic bacterium used in the clinic. When administered orally, it reduces allergic sensitisation but not allergic asthma. Intranasal administration offers a non-invasive and convenient delivery method. This route bypasses the gastrointestinal tract and provides direct access to the airways, which are the target of asthma prevention. G- bacteria such as E. coli O83 release outer membrane vesicles (OMVs) to communicate with the environment. Here we investigate whether intranasally administered E. coli O83 OMVs (EcO83-OMVs) can reduce allergic airway inflammation in mice. Methods EcO83-OMVs were isolated by ultracentrifugation and characterised their number, morphology (shape and size), composition (proteins and lipopolysaccharide; LPS), recognition by innate receptors (using transfected HEK293 cells) and immunomodulatory potential (in naïve splenocytes and bone marrow-derived dendritic cells; BMDCs). Their allergy-preventive effect was investigated in a mouse model of ovalbumin-induced allergic airway inflammation. Results EcO83-OMVs are spherical nanoparticles with a size of about 110 nm. They contain LPS and protein cargo. We identified a total of 1120 proteins, 136 of which were enriched in OMVs compared to parent bacteria. Proteins from the flagellum dominated. OMVs activated the pattern recognition receptors TLR2/4/5 as well as NOD1 and NOD2. EcO83-OMVs induced the production of pro- and anti-inflammatory cytokines in splenocytes and BMDCs. Intranasal administration of EcO83-OMVs inhibited airway hyperresponsiveness, and decreased airway eosinophilia, Th2 cytokine production and mucus secretion. Conclusions We demonstrate for the first time that intranasally administered OMVs from probiotic G- bacteria have an anti-allergic effect. Our study highlights the advantages of OMVs as a safe platform for the prophylactic treatment of allergy. Graphical Abstract Video Abstract

Abstract Introduction Accumulating clinical evidence links Obstructive Sleep Apnea (OSA) with worse outcomes of asthma, but impact on airway function remains sparsely studied. We tested effects of Chronic Intermittent Hypoxia (CIH) – a hallmark of OSA – on airway hyperresponsiveness (AHR), in a rat model of chronic allergen-induced inflammation. Methods Brown Norway rats were exposed to six weeks of CIH or normoxia (NORM) concurrent with weekly house dust mites (HDM) or saline (SAL) challenges. At endpoint, we assessed responses to seven Methacholine (Mch) doses (0, 4, 8, 16, 32, 64, 128 mg/mL) on a FlexiVent system (Scireq). Maximal (or plateau) responses (reactivity) for total respiratory system Resistance (Rrs) and Elastance (Ers), Newtonian airway resistance (RN, a measure of central airways function) and tissue damping (G, a measure of distal airways function) were plotted. Results HDM/CIH–treated animals demonstrated the highest reactivity to Mch in Rrs and Ers compared to all other groups (HDM/NORM, SAL/CIH and SAL/NORM p

Daily inhaled antigens induce cellular immune response in the airways. In case of allergens, allergic airway inflammation is usually represented by eosinophils, however, neutrophil infiltration is also observed during severe asthma. Animal models contribute to investigation of the mechanisms that involve the switching to eosinophil- or neutrophil-mediated inflammation. Data about the spatial location of eosinophils and neutrophils in the airways are necessary for both the understanding of allergic airway inflammation mechanisms and the drag potential estimation, however, not completely investigated. In the present study, we characterized the model of Aspergillus fumigatus extract-induced allergic airway inflammation that allowed investigating the early stage of inflammation development. The model adequacy was confirmed according to the blood and bronchoalveolar lavage eosinophilia. Using immunohistochemical staining of conducting airway as a whole-mount and confocal laser scanning microscopy, we estimated neutrophil and eosinophil spatial location: in the luminal side of the epithelium, in the airway wall or in the submucosal compartment close to the smooth muscle layer. An allergic airway response activation was detected upon significant elevation of blood eosinophil percentage compared to intact mice. Simultaneously, the number of eosinophils in the bronchoalveolar lavage was also significantly increased compared to the intact mice. At this time point, eosinophils predominated both in bronchoalveolar lavages and in conducting airway mucosa compared to neutrophils. Spatial location of conducting airway mucosal cell analysis demonstrated that eosinophils mostly located in the submucosal compartment, in a lesser extent in the airway wall, and a few eosinophils were detected in the luminal side of the epithelium. Neutrophils mainly infiltrated the luminal side of the epithelium, and a few neutrophils were detected in the submucosal compartment, while no neutrophils were detected in the airway wall. The data suggests that in response to the further allergen challenge, evidently eosinophils but not neutrophils will migrate through the airway wall to the airway lumen. Thus, eosinophils can be expected to damage airway epithelium in allergic airway inflammation development. Simultaneously, neutrophils located in close proximity to the smooth muscle layer together with eosinophils can contribute to bronchoconstriction induction.

Background: E. coli O83 (Colinfant Newborn) is a Gram-negative (G-) probiotic bacterium used in the clinic. When administered orally, it reduces allergic sensitisation but not allergic asthma. Intranasal administration offers a non-invasive and convenient delivery method. This route bypasses the gastrointestinal tract and provides direct access to the airways, which are the target of asthma prevention. G- bacteria such as E. coli O83 release outer membrane vesicles (OMVs) to communicate with the environment. Here we investigate whether intranasally administered E. coli O83 OMVs (EcO83-OMVs) can reduce allergic airway inflammation in mice. Methods: EcO83-OMVs were isolated by ultracentrifugation and characterised their number, morphology (shape and size), composition (proteins and lipopolysaccharide; LPS), recognition by innate receptors (using transfected HEK293 cells) and immunomodulatory potential (in naïve splenocytes and bone marrow-derived dendritic cells; BMDCs). Their allergy-preventive effect was investigated in a mouse model of ovalbumin-induced allergic airway inflammation. Results: EcO83-OMVs are spherical nanoparticles with a size of about 110 nm. They contain LPS and protein cargo. We identified a total of 1120 proteins, 136 of which were enriched in OMVs compared to parent bacteria. Proteins from the flagellum dominated. OMVs activated the pattern recognition receptors TLR2/4/5 as well as NOD1 and NOD2. EcO83-OMVs induced the production of pro- and anti-inflammatory cytokines in splenocytes and BMDCs. Intranasal administration of EcO83-OMVs inhibited airway hyperresponsiveness, and decreased airway eosinophilia, Th2 cytokine production and mucus secretion. Conclusions: We demonstrate for the first time that intranasally administered OMVs from probiotic G- bacteria have an anti-allergic effect. Our study highlights the advantages of OMVs as a safe platform for the prophylactic treatment of allergy. EMYsnR3rdE-GSR4j97-aGf Video Abstract [ABSTRACT FROM AUTHOR]

Allergic airway inflammation (AAI) is a chronic respiratory disease that is considered a severe restriction in daily life and is accompanied by a constant risk of acute aggravation. It is characterized by IgE-dependent activation of mast cells, infiltration of eosinophils, and activated T-helper cell type 2 (Th2) lymphocytes into airway mucosa. Purinergic receptor signaling is known to play a crucial role in inducing and maintaining allergic airway inflammation. Previous studies in an ovalbumin (OVA)-alum mouse model demonstrated a contribution of the P2Y2 purinergic receptor subtype (P2RY2) in allergic airway inflammation. However, conflicting data concerning the mechanism by which P2RY2 triggers AAI has been reported. Thus, we aimed at elucidating the celltype-specific role of P2RY2 signaling in house dust mite (HDM)-driven model of allergic airway inflammation. Thereupon, HDM-driven AAI was induced in conditional knockout mice, deficient or intact for P2ry2 in either alveolar epithelial cells, hematopoietic cells, myeloid cells, helper T cells, or dendritic cells. To analyze the functional role of P2RY2 in these mice models, flow cytometry of bronchoalveolar lavage fluid (BALF), cytokine measurement of BALF, invasive lung function measurement, HDM re-stimulation of mediastinal lymph node (MLN) cells, and lung histology were performed. Mice that were subjected to an HDM-based model of allergic airway inflammation resulted in reduced signs of acute airway inflammation including eosinophilia in BALF, peribronchial inflammation, Th2 cytokine production, and bronchial hyperresponsiveness in mice deficient for P2ry2 in alveolar epithelial cells, hematopoietic cells, myeloid cells, or dendritic cells. Furthermore, the migration of bone-marrow-derived dendritic cells and bone-marrow-derived monocytes, both deficient in P2ry2, towards ATP was impaired. Additionally, we found reduced levels of MCP-1/CCL2 and IL-8 homologues in the BALF of mice deficient in P2ry2 in myeloid cells and lower concentrations of IL-33 in the lung tissue of mice deficient in P2ry2 in alveolar epithelial cells. In summary, our results show that P2RY2 contributes to HDM-induced airway inflammation by mediating proinflammatory cytokine production in airway epithelial cells, monocytes, and dendritic cells and drives the recruitment of lung dendritic cells and monocytes. [ABSTRACT FROM AUTHOR]

Allergic airway inflammation (AAI) is a chronic respiratory disease that is considered a severe restriction in daily life and is accompanied by a constant risk of acute aggravation. It is characterized by IgE-dependent activation of mast cells, infiltration of eosinophils, and activated T-helper cell type 2 (Th2) lymphocytes into airway mucosa. Purinergic receptor signaling is known to play a crucial role in inducing and maintaining allergic airway inflammation. Previous studies in an ovalbumin (OVA)–alum mouse model demonstrated a contribution of the P2Y2 purinergic receptor subtype (P2RY2) in allergic airway inflammation. However, conflicting data concerning the mechanism by which P2RY2 triggers AAI has been reported. Thus, we aimed at elucidating the cell-type-specific role of P2RY2 signaling in house dust mite (HDM)-driven model of allergic airway inflammation. Thereupon, HDM-driven AAI was induced in conditional knockout mice, deficient or intact for P2ry2 in either alveolar epithelial cells, hematopoietic cells, myeloid cells, helper T cells, or dendritic cells. To analyze the functional role of P2RY2 in these mice models, flow cytometry of bronchoalveolar lavage fluid (BALF), cytokine measurement of BALF, invasive lung function measurement, HDM re-stimulation of mediastinal lymph node (MLN) cells, and lung histology were performed. Mice that were subjected to an HDM-based model of allergic airway inflammation resulted in reduced signs of acute airway inflammation including eosinophilia in BALF, peribronchial inflammation, Th2 cytokine production, and bronchial hyperresponsiveness in mice deficient for P2ry2 in alveolar epithelial cells, hematopoietic cells, myeloid cells, or dendritic cells. Furthermore, the migration of bone-marrow-derived dendritic cells and bone-marrow-derived monocytes, both deficient in P2ry2, towards ATP was impaired. Additionally, we found reduced levels of MCP-1/CCL2 and IL-8 homologues in the BALF of mice deficient in P2ry2 in myeloid cells and lower concentrations of IL-33 in the lung tissue of mice deficient in P2ry2 in alveolar epithelial cells. In summary, our results show that P2RY2 contributes to HDM-induced airway inflammation by mediating proinflammatory cytokine production in airway epithelial cells, monocytes, and dendritic cells and drives the recruitment of lung dendritic cells and monocytes.

• The prevalence of allergic diseases in the world reported so far is approximately 20%. • Long-term relief from allergic diseases is one of the major concerns worldwide and avoidance is to only management strategy. • Mesenchymal stem cells (MSCs) might be promising potential alternative treatment approach for allergy sufferers. • Recent evidence suggests that MSCs as immunomodulators for alleviating allergic airway inflammation and food allergy symptoms in mice. • Effect of short chain fatty acids (SCFAs) produced by gut microbes in regulation of the regeneration and differentiation of MSCs needs further investigation in the allergy treatment. Allergic diseases are broadly classified as IgE-mediated type-I hypersensitivity immune reactions due to exposure to typically harmless substances known as allergens. These allergenic substances activate antigen presenting cells, which further triggers T-helper 2 cells immune response and class switch B-cells for synthesis of allergen-specific IgE, followed by classical activation of inflammatory mast cells and eosinophils, which releases preformed mediators involved in the cascade of allergic symptoms. However, the role of Mesenchymal stem cells (MSCs) in tissue repair ability and immunomodulation, makes them as an appropriate tool for treatment of various allergic diseases. Several clinical and preclinical studies show that MSCs could be a promising alternative therapy to allergic diseases. Further, short chain fatty acids, produced from gut microbes by breaking down complex fibre-rich foods, acts through G-coupled receptor mediated activation of MSCs, and their role as key players involved in amelioration of allergic inflammation needs further investigation. Therefore, there is a need for understating the role of SCFAs on the activation of MSCs, which might shed light on the development of new therapeutic regime in allergy treatment. In summary, this review focuses on the underlying of therapeutic role of MSCs in different allergic diseases and the prospects of SCFA and MSC therapy. [ABSTRACT FROM AUTHOR]

Introduction: Accumulating clinical evidence links Obstructive Sleep Apnea (OSA) with worse outcomes of asthma, but impact on airway function remains sparsely studied. We tested effects of Chronic Intermittent Hypoxia (CIH) – a hallmark of OSA – on airway hyperresponsiveness (AHR), in a rat model of chronic allergen-induced inflammation. Methods: Brown Norway rats were exposed to six weeks of CIH or normoxia (NORM) concurrent with weekly house dust mites (HDM) or saline (SAL) challenges. At endpoint, we assessed responses to seven Methacholine (Mch) doses (0, 4, 8, 16, 32, 64, 128 mg/mL) on a FlexiVent system (Scireq). Maximal (or plateau) responses (reactivity) for total respiratory system Resistance (Rrs) and Elastance (Ers), Newtonian airway resistance (RN, a measure of central airways function) and tissue damping (G, a measure of distal airways function) were plotted. Results: HDM/CIH–treated animals demonstrated the highest reactivity to Mch in Rrs and Ers compared to all other groups (HDM/NORM, SAL/CIH and SAL/NORM p < 0.05 for all comparisons, for doses 5–7 for Rrs, and for doses 4–7 for Ers). The enhanced Rrs response was due to an increase in G (doses 4–7, p < 0.05 for comparisons to all other groups), whereas RN was not affected by CIH. Conclusions: In rats chronically challenged with HDM, concurrent CIH exposure induces AHR primarily in the distal airways, which affects the respiratory system frequency-dependent elastic properties. [ABSTRACT FROM AUTHOR]

The currently observed high prevalence of allergic diseases has been associated with changes in microbial exposure in industrialized countries. Defined bacterial components represent a new strategy for modulating the allergic immune response. We show that intranasal administration of exopolysaccharide (EPS) isolated from Lacticaseibacillus (L.) rhamnosus LOCK900 induces TGF‐β1, IgA, and regulatory FoxP3+ T‐cells in the lungs of naïve mice. Using the ovalbumin mouse model, we demonstrate that intranasal administration of EPS downregulates the development of allergic airway inflammation and the Th2 cytokine response in sensitized individuals. At the same time, EPS treatment of sensitized mice, similar to EPS‐induced responses in naïve mice, significantly increased the level of total, OVA‐specific, and also bacteria‐specific IgA in bronchoalveolar lavage and the number of IgA‐producing B‐cells in the lung tissue of these mice. Thus, EPS derived from L. rhamnosus LOCK900 can be considered a safe candidate for preventing the development of allergic symptoms in the lungs of sensitized individuals upon exposure to an allergen. [ABSTRACT FROM AUTHOR]

Dimerized translationally controlled tumor protein (dTCTP) initiates a variety of allergic responses in mouse models and that dTCTP-binding peptide 2 (dTBP2) attenuates the allergic inflammation by targeting dTCTP. However, the usefulness of peptide-based drugs is often limited due to their short half-lives, rapid degradation, and high levels of clearance after systemic administration. In this study, we chemically conjugated dTBP2 with 10 kDa polyethylene glycol (PEG) to improve its therapeutic potential. N-terminal mono-PEGylated dTBP2 (PEG-dTBP2) was characterized by in vitro bioactivity assay, pharmacokinetics study, and in vivo efficacy. When compared to the unmodified dTBP2, PEG-dTBP2 reduced proinflammatory cytokine IL-8 secretion in human bronchial cells by 10 to 15% and increased plasma half-life by approximately 2.5-fold in mice. This study specifically demonstrated that PEG-dTBP2 shows higher inhibitory action against ovalbumin (OVA)-induced airway inflammation in mice compared to dTBP2. Importantly, PEG-dTBP2, when administered once at 1 mg/kg, significantly reduced the migration of inflammatory cells and the levels of cytokines in the bronchoalveolar lavage fluids as well as OVA-specific IgE levels in serum. In addition, the degree of goblet cell hyperplasia and mucus secretion were significantly attenuated in the PEG-dTBP2 group compared with the control group. These results suggest that PEG-dTBP2 can be considered a potential candidate drug for regulating allergic inflammation.

Background: Dietary carbohydrates and fats are intrinsically correlated within the habitual diet. We aimed to disentangle the associations of starch and sucrose from those of fat, in relation to allergic sensitization, asthma and rhinoconjuctivitis prevalence in humans, and to investigate underlying mechanisms using murine models. Methods: Epidemiological data from participants of two German birth cohorts (age 15) were used in logistic regression analyses testing cross‐sectional associations of starch and sucrose (and their main dietary sources) with aeroallergen sensitization, asthma and rhinoconjunctivitis, adjusting for correlated fats (saturated, monounsaturated, omega‐6 and omega‐3 polyunsaturated) and other covariates. For mechanistic insights, murine models of aeroallergen‐induced allergic airway inflammation (AAI) fed with a low‐fat‐high‐sucrose or ‐high‐starch versus a high‐fat diet were used to characterize and quantify disease development. Metabolic and physiologic parameters were used to track outcomes of dietary interventions and cellular and molecular responses to monitor the development of AAI. Oxidative stress biomarkers were measured in murine sera or lung homogenates. Results: We demonstrate a direct association of dietary sucrose with asthma prevalence in males, while starch was associated with higher asthma prevalence in females. In mice, high‐carbohydrate feeding, despite scant metabolic effects, aggravated AAI compared to high‐fat in both sexes, as displayed by humoral response, mucus hypersecretion, lung inflammatory cell infiltration and TH2‐TH17 profiles. Compared to high‐fat, high‐carbohydrate intake was associated with increased pulmonary oxidative stress, signals of metabolic switch to glycolysis and decreased systemic anti‐oxidative capacity. Conclusion: High consumption of digestible carbohydrates is associated with an increased prevalence of asthma in humans and aggravated lung allergic inflammation in mice, involving oxidative stress‐related mechanisms. [ABSTRACT FROM AUTHOR]

Background: Probiotics may facilitate the clinical management of allergic diseases. However, their effects on allergic rhinitis (AR) remain unclear. We examined the efficacy and safety of Lacticaseibacillus paracasei GM-080 in a mouse model of airway hyper-responsiveness (AHR) and in children with perennial AR (PAR) by using a double-blind, prospective, randomized, placebo-controlled design. Methods: The production of interferon (IFN)-γ and interleukin (IL)-12 was measured by using an enzyme-linked immunosorbent assay. GM-080 safety was evaluated via the whole-genome sequencing (WGS) of virulence genes. An ovalbumin (OVA)-induced AHR mouse model was constructed, and lung inflammation was evaluated by measuring the infiltrating leukocyte content of bronchoalveolar lavage fluid. A clinical trial was conducted with 122 children with PAR who were randomized to receive different doses of GM-080 or the placebo for 3 months, and their AHR symptom severity scores, total nasal symptom scores (TNSSs), and Investigator Global Assessment Scale scores were examined. Results: Among the tested L. paracasei strains, GM-080 induced the highest IFN-γ and IL-12 levels in mouse splenocytes. WGS analysis revealed the absence of virulence factors or antibiotic-resistance genes in GM-080. The oral administration of GM-080 at 1 × 107 colony forming units (CFU)/mouse/day for 8 weeks alleviated OVA-induced AHR and reduced airway inflammation in mice. In children with PAR, the oral consumption of GM-080 at 2 × 109 CFU/day for 3 months ameliorated sneezing and improved Investigator Global Assessment Scale scores significantly. GM-080 consumption led to a nonsignificant decrease in TNSS and also nonsignificantly reduced IgE but increased INF-γ levels. Conclusion: GM-080 may be used as a nutrient supplement to alleviate airway allergic inflammation. [ABSTRACT FROM AUTHOR]

The current study was designed to investigate the potential anti‐inflammatory and antioxidant effects of fingolimod against Ovalbumin (Ova)‐induced allergic airway inflammation compared to dexamethasone. Fingolimod was given (0.5 mg/kg/day, p.o.) for sensitized mice 1 h before Ova challenge from Days 19 to 24. Fingolimod significantly inhibited Ova‐induced elevation of inflammatory cells and eosinophils numbers in bronchoalveolar lavage fluid (BALF) and reduced concentrations of immunoglobulin E in serum and of sphingosine‐1‐phosphate, interleukin (IL)‐4, and IL‐13 in BALF. Fingolimod inhibited microvascular leakage and edema as reflected by the decreased lung/body weight index. These findings were supported by histopathological examination results showing that fingolimod substantially decreased perivascular edema and inflammatory cell infiltration. Fingolimod also attenuated Ova‐induced oxidative stress as evidenced by decreased malondialdehyde concentration along with increasing concentrations of reduced glutathione and superoxide dismutase in lung tissues. Fingolimod also significantly decreased monocyte chemoattractant protein‐1 (MCP‐1), p‐ERK, and p‐P38 in lung tissues of Ova‐challenged mice. In conclusion, the current study demonstrated the anti‐inflammatory and antioxidant effects of fingolimod in allergic airway inflammation that might be associated with the downregulation of mitogen activated kinases signaling to decrease T helper 2 cytokine secretion (IL‐4 and IL‐13) and MCP‐1 expression, along with the inhibition of oxidative stress. [ABSTRACT FROM AUTHOR]

ABSTRACT House dust mites (HDMs) are a major source of indoor allergens that cause airway allergic disease. Dermatophagoides farinae, a predominant species of HDMs in China, has demonstrated pathogenic role in allergic disorders. Exosomes derived from human bronchoalveolar lavage fluid have been strongly associated with allergic respiratory diseases progression. However, the pathogenic role of D. farinae-derived exosomes in allergic airway inflammation has remained unclear until now. Here, D. farinae was stirred overnight in phosphate-buffered saline, and the supernatant was used to extract exosomes by ultracentrifugation. Then, shotgun liquid chromatography-tandem mass spectrometry and small RNA sequencing were performed to identify proteins and microRNAs contained in D. farinae exosomes. Immunoblotting, Western blotting, and enzyme-linked immunosorbent assay demonstrated the specific immunoreactivity of D. farinae-specific serum IgE antibody against D. farinae exosomes, and D. farinae exosomes were found to induce allergic airway inflammation in a mouse model. In addition, D. farinae exosomes invaded 16-HBE bronchial epithelial cells and NR8383 alveolar macrophages to release the inflammation-related cytokines interleukin-33 (IL-33), thymic stromal lymphopoietin, tumor necrosis factor alpha, and IL-6, and comparative transcriptomic analysis of 16-HBE and NR8383 cells revealed that immune pathways and immune cytokines/chemokines were involved in the sensitization of D. farinae exosomes. Taken together, our data demonstrate that D. farinae exosomes are immunogenic and may induce allergic airway inflammation via bronchial epithelial cells and alveolar macrophages. IMPORTANCE Dermatophagoides farinae, a predominant species of house dust mites in China, has displayed pathogenic role in allergic disorders, and exosomes derived from human bronchoalveolar lavage fluid have been strongly associated with allergic respiratory diseases progression. However, the pathogenic role of D. farinae-derived exosomes in allergic airway inflammation has remained unclear until now. This study, for the first time, extracted exosomes from D. farinae, and sequenced their protein cargo and microRNAs using shotgun liquid chromatography-tandem mass spectrometry and small RNA sequencing. D. farinae-derived exosomes trigger allergen-specific immune responses and present satisfactory immunogenicity, as revealed by immunoblotting, Western blotting, and enzyme-linked immunosorbent assay and may induce allergic airway inflammation via bronchial epithelial cells and alveolar macrophages. Our data provide insights into the mechanisms of allergic airway inflammation caused with D. farinae-derived exosomes and the treatment of house dust mite-induced allergic airway inflammation.

Arachidonic acid metabolites resulting from the cyclooxygenase (COX), lipoxygenase, and cytochrome P450 oxidase enzymatic pathways play pro- and anti-inflammatory roles in allergic airway inflammation (AAI) and asthma. Expression of COX-2 and soluble epoxide hydrolase (sEH) are elevated in allergic airways and their enzymatic products (e.g., prostaglandins and diols of epoxyeicosatrienoic acids, respectively) have been shown to participate in the pathogenesis of AAI. Here, we evaluated the outcome of inhibiting the COX-2 and sEH enzymatic pathways with a novel dual inhibitor, PTUPB, in A. alternata-induced AAI. Allergen-challenged mice were administered with 10 or 30 mg/kg of PTUPB, celecoxib (selective COX-2 inhibitor), t-TUCB (selective sEH inhibitor) or vehicle daily by gavage and evaluated for various features of AAI. PTUPB and t-TUCB at 30 mg/kg, but not celecoxib, inhibited eosinophilic infiltration and significantly increased levels of anti-inflammatory EETs in the lung tissue of allergen-challenged mice. t-TUCB significantly inhibited allergen-induced IL-4 and IL-13, while a less pronounced reduction was noted with PTUPB and celecoxib. Additionally, t-TUCB markedly inhibited eotaxin-2, an eosinophil-specific chemokine, which was only marginally reduced by PTUPB and remained elevated in celecoxib-treated mice. PTUPB or t-TUCB administration reversed allergen-induced reduction in levels of various lipid mediators in the lungs, with only a minimal effect noted with celecoxib. Despite the anti-inflammatory effects, PTUPB or t-TUCB did not reduce allergen-induced airway hyperresponsiveness (AHR). However, development of structural changes in the allergic airways, such as mucus hypersecretion and smooth muscle hypertrophy, was significantly inhibited by both inhibitors. Celecoxib, on the other hand, inhibited only airway smooth muscle hypertrophy, but not mucus hypersecretion. In conclusion, dual inhibition of COX-2 and sEH offers no additional advantage relative to sEH inhibition alone in attenuating various features associated with A. alternata-induced AAI, while COX-2 inhibition exerts only moderate or no effect on several of these features. Dual sEH/COX-2 inhibition may be useful in treating conditions where eosinophilic inflammation co-exists with pain-associated inflammation.

BackgroundAltered epithelial physical and functional barrier properties along with TH1/TH2 immune dysregulation are features of allergic asthma. Regulation of junction proteins to improve barrier function of airway epithelial cells has the potential for alleviation of allergic airway inflammation.ObjectiveWe sought to determine the immunomodulatory effect of knob protein of the adenoviral capsid on allergic asthma and to investigate its mechanism of action on airway epithelial junction proteins and barrier function.MethodsAirway inflammation, including junction protein expression, was evaluated in allergen-challenged mice with and without treatment with knob. Human bronchial epithelial cells were exposed to knob, and its effects on expression of junction proteins and barrier integrity were determined.ResultsAdministration of knob to allergen-challenged mice suppressed airway inflammation (eosinophilia, airway hyperresponsiveness, and IL-5 levels) and prevented allergen-induced loss of airway epithelial occludin and E-cadherin expression. Additionally, knob decreased expression of TH2-promoting inflammatory mediators, specifically IL-33, by murine lung epithelial cells. At a cellular level, treatment of human bronchial epithelial cells with knob activated c-Jun N-terminal kinase, increased expression of occludin and E-cadherin, and enhanced epithelial barrier integrity.ConclusionIncreased expression of junction proteins mediated by knob leading to enhanced epithelial barrier function might mitigate the allergen-induced airway inflammatory response, including asthma.

Itaconate has emerged as a novel anti-inflammatory and antioxidative endogenous metabolite, yet its role in allergic airway inflammation (AAI) and the underlying mechanism remains elusive. Here, the itaconate level in the lung was assessed by High Performance Liquid Chromatography (HPLC), and the effects of the Irg1/itaconate pathway on AAI and alveolar macrophage (AM) immune responses were evaluated using an ovalbumin (OVA)-induced AAI model established by wild type (WT) and Irg1−/− mice, while the mechanism of this process was investigated by metabolomics analysis, mitochondrial/cytosolic protein fractionation and transmission electron microscopy in the lung tissues. The results demonstrated that the Irg1 mRNA/protein expression and itaconate production in the lung were significantly induced by OVA. Itaconate ameliorated while Irg1 deficiency augmented AAI, and this may be attributed to the fact that itaconate suppressed mitochondrial events such as NLRP3 inflammasome activation, oxidative stress and metabolic dysfunction. Furthermore, we identified that the Irg1/itaconate pathway impacted the NLRP3 inflammasome activation and oxidative stress in AMs. Collectively, our findings provide evidence for the first time, supporting the conclusion that in the allergic lung, the itaconate level is markedly increased, which directly regulates AMs' immune responses. We therefore propose that the Irg1/itaconate pathway in AMs is a potential anti-inflammatory and anti-oxidative therapeutic target for AAI. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is widely used in manufacturing plastic products, and it has been reported that exposure through the airway or orally aggravates allergic airway inflammation. Because BPA is detected in the atmosphere and indoor environments, the eyes can also be exposed to BPA. After ocular exposure to BPA and antigen via eye drops, we observed enhanced antigen uptake of antigen-presenting cells (APCs) in tear duct-associated lymphoid tissue (TALT). Additionally, we observed the formation of germinal center (GC) B cells in TALT and induction of allergic airway inflammation in mice sensitized with BPA and antigen via eye drops, followed by airway antigen exposure. We also found that DNAX-activating protein of 12 kDa (DAP12)-deficient mice displayed impaired activation of APCs enhanced by ocular exposure to BPA. These results indicate that ocular sensitization to BPA and allergen triggers allergic inflammation via TALT activation, and that DAP12 might be a key molecule for modulating the ocular immune system. [ABSTRACT FROM AUTHOR]

Ambient particulate matter (PM) exacerbates airway inflammation and hyper-reactivity in asthmatic patients. Studies show that PM has adjuvant-like properties that enhance the allergic inflammatory response; however, the mechanisms through which PM enhances these processes remain elusive. The objective of the study was to examine how ambient PM enhances the allergic immune response. Eight-week-old BALB/c mice were sensitized with house dust mite (HDM) or HDM and ambient particulate matter (PM, 2.5 μm; Sacramento, CA) to assess how PM modulates the development of adaptive immune responses against allergens. Both groups were challenged with HDM only. Bronchoalveolar lavage (BAL) was analyzed for extent of airway inflammation. Lung tissue was used for histological analysis, mucosubstance quantification, and heme oxygenase-1 (HO-1) localization/quantification. Gene expression was analyzed in whole lung to characterize immune markers of inflammation: cytokines, chemokines, antioxidant enzymes, and transcription factors. Cytokine and chemokine protein levels were quantified in whole lung to confirm gene expression patterns. Compared to HDM-only sensitization, exposure to PM during HDM sensitization led to significant immune cell recruitment into the airway subepithelium, IgE gene expression, mucosubstance production, and Th2-associated cytokine expression. HO-1 levels were not significantly different between the treatment groups. Gene expression profiles suggest that polycyclic aromatic hydrocarbon (PAH) content in PM activated the aryl hydrocarbon receptor (AhR) and enhanced Th17-responses in the mice that received HDM and PM compared to mice that received HDM-only. The findings suggest that PM enhances allergic sensitization via enhancement of Th2-mediated inflammation and that AhR activation by PAHs in PM promotes Th17-immune responses.

Mucosal-associated invariant T (MAIT) cells, a blossoming member of the innatelike T cells, play a pivotal role in host defense through engaging the mucosal immunity. Although it has been suggested that MAIT cells are somehow implicated in the allergic airway inflammation mediated by group 2 innate lymphoid cells (ILC2s) such as asthma, the precise role(s) of MAIT cells in such inflammation has remained elusive. To explore the possible roles of MAIT cells in the inflammation, we examined whether MAIT cells suppressed the production of T helper (Th) 2 and inflammatory cytokines from ILC2s, and constrained the proliferation of ILC2s, both of which are prerequisite for airway inflammation. Given that laboratorymice are poor at MAIT cells, a novel mouse line rich inMAIT cells was used. We found that mice rich in MAIT cells showed alleviated airway inflammation as evidenced by reduced infiltration of the immune cells and hyperplasia in goblet cells in the lung concomitant with compromised production of Th2 and inflammatory cytokines, while wild type mice exhibited severe inflammation upon challenge with the fungal extracts. In vitro coculture experiments using purified ILC2s and MAIT cells unrevealed that cytokinestimulated MAIT cells suppressed ILC2s to produce the cytokines as well as to proliferatemost likely via production of IFN-γ. Furthermore, reconstitution of the allergic airway inflammation in the highly immunocompromised mice showed that ILC2-mediated inflammation was alleviated in mice that received MAIT cells along with ILC2s. We concluded that MAIT cells played a crucial role in suppressing the cytokine-producing capacity of ILC2s and ILC2 proliferation, that ultimately led to decrease in the allergic airway inflammation. The results open up a novel therapeutic horizon in ILC2-mediated inflammatory diseases by modulating MAIT cell activity. [ABSTRACT FROM AUTHOR]

Three isoforms of secretoglobin (SCGB) 3A2, namely type A, B, and C, are endogenously produced through alternative splicing. SCGB3A2 type A, the correctly spliced major type, begins to be expressed from embryonic day 11.5 in mice and shows various physiological activities such as promoting lung maturation and bronchial branching, anti-inflammatory effects, and ameliorating induced pulmonary fibrosis. To investigate the potential of SCGB3A2 peptides as a therapeutic to treat respiratory diseases, in this study, serially overlapping nine peptides were synthesized to cover the entire type C isoform, and five and one peptides covering the C-terminal region of type A and B, respectively. To evaluate their biological activities, each peptide was subjected to cell proliferation and apoptosis analyses in vitro using mouse lung fibroblast-derived MLg cells, bronchial branching rate using ex vivo mouse fetal lung organ cultures, and in vivo allergic airway inflammation mouse model. Among type A and C peptides, those corresponding to the C-terminal region of the SCGB3A2 sequence exhibited its unique biological activities of promoting cell proliferation and bronchial branching, and/or inhibiting apoptosis. The type B peptide did not show any proliferative effect while inhibited apoptosis. In a mouse model of allergic airway inflammation, lung inflammation was improved by the administration of most of the C-terminal region-derived type A and type C peptides. The results suggest that the bioactivity resides towards the C-terminal region of SCGB3A2 sequence, and the peptides covering this region could be used as a therapeutic in treating lung inflammation., Competing Interests: Declaration of competing interest The authors have declared that no competing interest exists., (Copyright © 2024 Elsevier Inc. All rights reserved.)

While much is known about the functional effects of type 2 cytokines interleukin (IL)-4, IL-5 and IL-13 in homeostasis and disease, we still poorly understand the functions of IL-9. Chronic inflammation seen in allergic diseases, autoimmunity and cancer is however frequently accompanied by overproduction of this elusive type 2 cytokine. Initially identified as a T cell and mast cell growth factor, and later as the hallmark cytokine defining T H 9 cells, we now know that IL-9 is produced by multiple innate and adaptive immune cells. Recent evidence suggests that IL-9 controls discrete aspects of the allergic cascade, cellular responses of immune and stromal cells, cancer progression, tolerance and immune escape. Despite functioning as a pleiotropic cytokine in mucosal environments, like the lungs, the direct and indirect cellular targets of IL-9 are still not well characterized. Here, we discuss IL-9's cellular senders and receivers, focusing on asthma and cancer. Moreover, we review current research directions and the outlook of targeted therapy centered around the biology of IL-9., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: C.B. is consultant and shareholder of argenx. B.N.L. receives consultancy fees from GSK Biologics, Novartis, Sanofi, AstraZeneca, ALK, OncoArendi, argenx and has research grants from ALK, argenx, AstraZeneca, GSK, GSK Biologics and Johnson & Johnson. All other authors have nothing to disclose., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Introduction: Allergic asthma is prevalent in children, with Dermatophagoides farinae as a common indoor allergen. Current treatments for allergic airway inflammation are limited and carry risks. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) show promise as a cell-free therapeutic approach. However, the use of engineered MSC-EVs for D. farinae-induced allergic airway epithelial cell inflammation remains unexplored., Methods: We generated miR-146a-5p-engineered EVs from human umbilical cord mesenchymal stem cells (hucMSCs) and established D. farinae-induced mouse and human bronchial epithelial cell allergic models. Levels of IL-1β, IL-18, IL-4, IL-5, IL-6, IL-10, IL-33, TNF-α and IgE were detected using ELISA. The relative TRAF6 and IRAK1 mRNA expression was quantified using qPCR assay and the NLRP3, NF-κB, IRAK1 and TRAF6 protein expression was determined using Western blotting. The regulatory effect of IRAK1 and TRAF6 by miR-146a-5p was examined using a dual luciferase reporter assay, and the nuclear translocation of NF-κB p65 into 16-HBE cells was evaluated using immunofluorescence assay., Results: Treatment with hucMSC-EVs effectively reduced allergic inflammation, while miR-146a-5p engineered hucMSC-EVs showed greater efficacy. The enhanced efficacy in alleviating allergic airway inflammation was attributed to the downregulation of IRAK1 and TRAF6 expression, facilitated by miR-146a-5p. This downregulation subsequently led to a decrease in NF-κB nuclear translocation, which in turn resulted in reduced activation of the NLRP3 inflammasome and diminished production of inflammatory cytokines, including IL-6, TNF-α, IL-1β and IL-18., Conclusion: Our study underscores the potential of miR-146a-5p engineered hucMSC-EVs as a cell-free therapeutic strategy for D. farinae-induced allergic airway inflammation, offering a promising avenue for boosting anti-inflammatory responses., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Liu, Xu, Yu, Zang, Jiang, Xu, Wang and Hong.)

Allergen-specific IgE is a major mediator of allergic responses and contributes greatly to allergic disease in the human population. Therapies that inhibit the production of IgE would be useful for lessening the burden of allergic disease. A great deal of research has focused on how IgE responses are regulated, and several factors that promote the production of allergic IgE have been characterized. T follicular helper (TFH) cells expressing IL-4 are required for the development of IgE expressing B cells in the germinal center (GC). Ig somatic hypermutation and B cell selection in the GC leads to the development of high affinity allergen-specific IgE that promotes anaphylaxis, a severe form of allergic response. T follicular regulatory (TFR) cells are also found in the GC response and act with TFH cells in the selection of high affinity IgE + B cells. This review examines the current literature on IgE responses and TFR cells. In mouse studies, TFR cells have a suppressive role on IgE responses in allergic airway disease, however TFR cells also play a helper role in the IgE response in food allergy. In human studies, TFR cells correlate with a decreased allergic response but evidence for a direct suppressive role of TFR cells on IgE in vivo is lacking. TFR cells may represent a new target for allergy therapies, but caution must be exercised to promote the suppressor activity of TFR cells and not the helper activity of TFR cells on IgE responses., (Copyright © 2024 Japanese Society of Allergology. Published by Elsevier B.V. All rights reserved.)

The high percentage of Vermamoeba was found in tap water in Korea. This study investigated whether Vermamoeba induced allergic airway inflammation in mice. We selected 2 free-living amoebas (FLAs) isolated from tap water, which included Korean FLA 5 (KFA5; Vermamoeba vermiformis) and 21 (an homolog of Acanthamoeba lugdunensis KA/E2). We axenically cultured KFA5 and KFA21. We applied approximately 1×106 to mice's nasal passages 6 times and investigated their pathogenicity. The airway resistance value was significantly increased after KFA5 and KFA21 treatments. The eosinophil recruitment and goblet cell hyperplasia were concomitantly observed in bronchial alveolar lavage (BAL) fluid and lung tissue in mice infected with KFA5 and KFA21. These infections also activated the Th2-related interleukin 25, thymic stromal lymphopoietin, and thymus and activation-regulated chemokines gene expression in mouse lung epithelial cells. The CD4+ interleukin 4+ cell population was increased in the lung, and the secretion of Th2-, Th17-, and Th1-associated cytokines were upregulated during KFA5 and KFA21 infection in the spleen, lung-draining lymph nodes, and BAL fluid. The pathogenicity (allergenicity) of KFA5 and KFA21 might not have drastically changed during the long-term in vitro culture. Our results suggested that Vermamoeba could elicit allergic airway inflammation and may be an airway allergen. [ABSTRACT FROM AUTHOR]

Interleukin 23 and the interleukin 23 receptor (IL-23-IL23R) are described as the major enhancing factors for Interleukin 17 (IL-17) in allergic airway inflammation. IL-17 is considered to induce neutrophilic inflammation in the lung, which is often observed in severe, steroid-resistant asthma-phenotypes. For that reason, understanding of IL-23 and IL-17 axis is very important for future therapy strategies, targeting neutrophil pathway of bronchial asthma. This study aimed to investigate the distribution and expression of IL-23R under physiological and inflammatory conditions. Therefore, a house dust mite (HDM) model of allergic airway inflammation was performed by treating mice with HDM intranasally. Immunofluorescence staining with panel of antibodies was performed in lung tissues to examine the macrophage, dendritic cell, and T cell subpopulations. The allergic airway inflammation was quantified by histopathological analysis, ELISA measurements, and airway function. HDM-treated mice exhibited a significant allergic airway inflammation including higher amounts of NE+ cells in lung parenchyma. We found only a small amount of IL-23R positives, out of total CD3+T cells, and no upregulation in HDM-treated animals. In contrast, the populations of F4/80+ macrophages and CD11c+F4/80− dendritic cells (DCs) with IL-23R expression were found to be higher. But HDM treatment leads to a significant increase of IL-23R+ macrophages, only. IL-23R was expressed by every examined macrophage subpopulation, whereas only Mϕ1 and hybrids between Mϕ1 and Mϕ2 phenotype and not Mϕ2 were found to upregulate IL-23R. Co-localization of IL-23R and IL-17 was only observed in F4/80+ macrophages, suggesting F4/80+ macrophages express IL-23R along with IL-17 in lung tissue. The study revealed that macrophages involving the IL-23 and IL-17 pathway may provide a potential interesting therapeutic target in neutrophilic bronchial asthma. [ABSTRACT FROM AUTHOR]

Asthma is a multifactorial disorder characterized by the airway chronic inflammation, hyper-responsiveness (AHR), remodeling, and reversible obstruction. Although asthma is known as a heterogeneous group of diseases with various clinical manifestations, recent studies suggest that more than half of the clinical cases are "T helper type 2 (Th2)-high" type, whose pathogenesis is driven by Th2 responses to an inhaled allergen from the environmental exposures. The intensity and duration of inflammatory responses to inhaled allergens largely depend on the balance between effector and regulatory cells, but many questions regarding the mechanisms by which the relative magnitudes of these opposing forces are remained unanswered. Regulatory T cells (Tregs), which comprise diverse subtypes with suppressive function, have long been attracted extensive attention owing to their capability to limit the development and progression of allergic diseases. In this review we seek to update the recent advances that support an essential role for Tregs in the induction of allergen tolerance and attenuation of asthma progression once allergic airway inflammation established. We also discuss the current concepts about Treg induction and Treg-expressed mediators relevant to controlling asthma, and the therapies designed based on these novel insights against asthma in clinical settings. [ABSTRACT FROM AUTHOR]

Yan Zhou,1,&ast; Yishu Xue,1,&ast; Aihua Bao,1,&ast; Lei Han,1 Wuping Bao,1 Chao Xia,2 Xue Tian,1 Min Zhang1 1Department of Respiratory and Critical Care Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200081, People’s Republic of China; 2Department of Gerontology, Xin Hua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Min ZhangDepartment of Respiratory and Critical Care Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 100 Haining Road, Hongkou District, Shanghai, 200080, People’s Republic of ChinaTel +86 21 63071428Email min.zhang@shgh.cnBackground and Objective: Vitamin D is involved in various physiological and pathological processes, including inflammation and autophagy. We aimed to investigate the effects of dietary vitamin D deficiency or supplementation initiated in lactation and early life on inflammation and autophagy in an ovalbumin (OVA) mouse model.Methods: Female BALB/c were fed with vitamin D-deficient, sufficient or supplemented diets throughout lactation and their offspring followed the same diet after weaning. Offspring were then sensitized and challenged with OVA, airway resistance (RL) was measured, and their serum, bronchoalveolar lavage fluid (BALF), and lung tissue were collected. Alveolar macrophages (AMs) were isolated from lung tissue and cultured with different concentrations of 1,25(OH)2D3. The expressions of autophagy-related (ATG) proteins including light-chain 3 (LC3), Beclin-1, and ATG5, and NF-κB p65 in lung tissue and AMs were measured.Results: OVA sensitization and challenge induced dramatic allergic airway inflammation and higher RL in the vitamin D-deficient group compared with vitamin D-sufficient or the supplemented group. The expression of ATGs including LC3, Beclin-1, and ATG5, and NF-κB p65 in lung tissue in the vitamin D-deficient OVA-mediated group was increased compared with vitamin D-supplemented OVA-mediated group. There was correlation between the expression of LC3 mRNA and inflammatory cell numbers and cytokines in BALF. In vitro, 1,25(OH)2D3 also regulated the expression of LC3, Beclin-1, ATG5, and NF-κB p65 mRNA in AMs in a time- and dose-dependent manner.Conclusion: Deficiency of vitamin D in early life may aggravate allergic airway inflammation, and maintaining sufficient vitamin D during early life is necessary for lung health. Vitamin D may modulate autophagy in lungs of OVA sensitized/challenged mice, thus playing a protective role in OVA-induced allergic airway inflammation.Keywords: vitamin D, allergic airway inflammation, asthma, autophagy, LC3, Beclin-1, ATG5

Scutellaria baicalensis Georgi (SCB, Huangqin) is a traditional medicinal plant used to treat fever and respiratory diseases. SCB has a good therapeutic effect on asthma and anti-inflammation in traditional clinic use. However, the molecular mechanism and targets of SCB in treating asthma are still unclear. Combining transcriptomic analysis and in vitro experimental validation, this study aimed to reveal the molecular mechanism and targets of SCB in treating asthma. The anti-asthmatic effects of SCB and its active components, scutellarin and oroxylin A, were evaluated in ovalbumin (OVA)-induced rats by analysis of pulmonary function and pathology. The signaling pathways in rat pulmonary tissue were analyzed using transcriptomics and protein interaction network analysis. Calcium mobilization assay and molecular docking were utilized to discover the active compounds from SCB with agonism activity of type 2 taste receptors (TAS2Rs). The anti-asthmatic effect and transcriptional regulation of TAS2Rs regulated by SCB and its active components were analyzed in vitro. Extracts of SCB (ESB), scutellarin, and oroxylin A ameliorated airway function and inflammation in OVA-induced rats. The anti-asthma mechanism of ESB, scutellarin and oroxylin A was highly related to immune and taste transduction pathways based on transcriptomic analysis, especially the TAS2Rs signaling pathway. ESB was the direct agonist of TAS2R4 and TAS2R14 with EC 50 of 209.1 and 217.2 μg/mL based on calcium mobilization assay, respectively. Baicalein was the main active component for TAS2R4 agonism activity, and scutellarin and oroxylin A had weak agonism activity of TAS2R4 and TAS2R14 through calcium mobilization assay and molecular docking. However, scutellarin and oroxylin A significantly upregulated the gene expression of Tas2r108 (the mouse ortholog of the TAS2R4) in lung tissue. ESB, scutellarin, and oroxylin A inhibited LPS-induced lactate dehydrogenase release and gene expression of TNF through transcriptional regulation of TAS2R4 and TAS2R14 on bronchial epithelial cells. ESB and oroxylin A ameliorated IgE-induced β-hexosaminidase release and gene expression of Il4 and Tnf and upregulated gene expression of Tas2r108. These results provided new insight into the anti-asthmatic mechanism of SCB and active components, scutellarin and oroxylin A, through agonism and transcriptional regulation of TAS2Rs to ameliorate allergic airway inflammation. [Display omitted] [ABSTRACT FROM AUTHOR]

The prevalence of allergic airway inflammation (AAI) worldwide is high. Artemisia annua L. pollen is spread worldwide, and allergic diseases caused by its plant polysaccharides, which are closely related to the intestinal microbiota, have anti-inflammatory effects. Further isolation and purification of Lycium barbarum L. yielded its most effective component Lycium barbarum L. glycopeptide (LbGP), which can inhibit inflammation in animal models. However, its therapeutic effect on AAI and its mechanism of regulating the intestinal flora have not been fully investigated. To explore LbGP in APE-induced immunological mechanisms of AAI and the interaction mechanism of the intestinal flora and metabolites. A mouse model of AAI generated from Artemisia annua pollen was constructed, and immunological indices related to the disease were examined. A combination of macrogenomic and metabolomic analyses was used to investigate the effects of LbGP on the gut microbial and metabolite profiles of mice with airway inflammation. LbGP effectively alleviated Artemisia. annua pollen extract (APE)-induced AAI, corrected Th1/Th2 immune dysregulation, decreased Th17 cells, increased Treg cells, and altered the composition and function of the intestinal microbiota. LbGP treatment increased the number of Odoribacter and Duncaniella in the intestines of the mice, but the numble of Alistipes and Ruminococcus decreased. Metabolite pathway enrichment analysis were used to determine the effects of taurine and hypotaurine metabolism, bile acid secretion, and pyrimidine metabolism pathways on disease. Our results revealed significant changes in the macrogenome and metabolome following APE and LbGP intervention, revealed potential correlations between gut microbial species and metabolites, and highlighted the beneficial effects of LbGP on AAI through the modulation of the gut microbiome and host metabolism. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • SAA1 secreted by airway epithelial cells was increased in patients and mice with allergic airway inflammation. • SAA1 promoted the release of CCL17 in M2 but not naïve macrophages in human and mice. • SAA1 induced the proinflammatory function of mouse macrophages via CD36 in allergic airway inflammation. Previous studies showed that serum amyloid A (SAA) and macrophages were associated with allergic airway inflammation. However, the interaction between SAA1 and macrophages in allergic airway inflammation remains to be further elucidated. In this study, the levels of SAA1 were measured in nasal tissues from patients with eosinophilic chronic rhinosinusitis with nasal polyps (CRSwNP), house dust mite (HDM)-treated BEAS-2B cells and the tissues of mice of HDM-induced allergic airway inflammation. Human monocytes-derived macrophages and mouse bone marrow-derived macrophages (BMDMs) were exposed to SAA1, and CCL17 and the other M1/M2-related factors were evaluated using RT-PCR and/or ELISA. To test the effects of SAA1-treated BMDMs on chemotaxis and differentiation of CD4+ T cells, number of migrated cells and the levels of Th1 and Th2 were measured using flow cytometry. SAA1 receptors were examined in BMDMs and lung macrophages of model mice. CD36 neutralizing antibody was applied to explore the mechanisms of SAA1 in regulating BMDMs using RT-PCR and/or ELISA. We found that SAA1 was expressed in epithelial cells, and was increased in the nasal tissues of patients with eosinophilic CRSwNP and HDM-treated BEAS-2B- cells as well as the bronchoalveolar lavage fluid and lung tissues of mice exposed to HDM. We also found that the level of CCL17 was increased in M2 macrophages, more CD4+ T cells were recruited and proportion of Th2 was increased after the treatment of SAA1. The treatment of CD36 neutralizing antibody decreased CCL17 level in SAA1-treated M2 BMDMs. In summary, our results showed that SAA1 was increased in allergic airway inflammation, and the administration of SAA1 upregulated the expression of CCL17 in M2 macrophages via CD36 and promoted the chemotaxis of CD4+ T cells and differentiation of Th2. It may provide a new therapeutic strategy that could mediate allergic airway inflammation via suppressing SAA1 to reduce recruitment of CD4+ T cells and activation of Th2. [ABSTRACT FROM AUTHOR]

Asthma is a multifactorial disorder characterized by the airway chronic inflammation, hyper-responsiveness (AHR), remodeling, and reversible obstruction. Although asthma is known as a heterogeneous group of diseases with various clinical manifestations, recent studies suggest that more than half of the clinical cases are ‘‘T helper type 2 (Th2)-high’’ type, whose pathogenesis is driven by Th2 responses to an inhaled allergen from the environmental exposures. The intensity and duration of inflammatory responses to inhaled allergens largely depend on the balance between effector and regulatory cells, but many questions regarding the mechanisms by which the relative magnitudes of these opposing forces are remained unanswered. Regulatory T cells (Tregs), which comprise diverse subtypes with suppressive function, have long been attracted extensive attention owing to their capability to limit the development and progression of allergic diseases. In this review we seek to update the recent advances that support an essential role for Tregs in the induction of allergen tolerance and attenuation of asthma progression once allergic airway inflammation established. We also discuss the current concepts about Treg induction and Treg-expressed mediators relevant to controlling asthma, and the therapies designed based on these novel insights against asthma in clinical settings.

P. odoratum polysaccharide alleviates allergic airway inflammation via the gut microbiota is associated with inhibiting the migration of ILC2s from the gut to the lung. [Display omitted] • P. odoratum polysaccharide (POP) ameliorated the OVA-induced allergic airway inflammation. • The beneficial effects of POP were associated with modulating the gut microbiota. • POP inhibited the migration of intestinal ILC2s towards the lung. Polygonatum odoratum is widely recognized to conribute to various health benefits, primarily attributed to its polysaccharide (POP). Polysaccharides are not directly and readily absorbed by the gastrointestinal system, but can interact with the gut microbes. This study aims to clarify the mechanism of POP in mitigating and preventing OVA-induced allergic airway inflammation via the gut-lung axis. The results showed that POP improved the symptoms associated with allergic respiratory responses, and the efficacy of POP was impeded due to the disruption of gut microbiota caused by antibiotics. The POP altered gut microbiota effectively alleviated the type 2 inflammation, reduced the number of ILC2s in the lung and gut, and inhibited the movement of intestinal ILC2s towards the lung. Clostridia UCG-014 and Rikenellaceae RC9 were figured out as pathogenic bacteria inhibited by POP. This study provides a reference for therapeutic application of POP in managing allergic airway inflammation via the gut-lung axis. [ABSTRACT FROM AUTHOR]