Ovalbumin Challenge Research Articles

CD5L attenuates allergic airway inflammation by expanding CD11chigh alveolar macrophages and inhibiting NLRP3 inflammasome activation via HDAC2.

Allergic asthma is an airway inflammatory disease dominated by type 2 immune responses and there is currently no curative therapy for asthma. CD5-like antigen (CD5L) has been known to be involved in a variety of inflammatory diseases. However, the role of CD5L in allergic asthma remains unclear. In the present study, mice were treated with recombinant CD5L (rCD5L) during house dust mite (HDM) and ovalbumin (OVA) challenge to determine the role of CD5L in allergic asthma, and the underlying mechanism was further explored. Compared with PBS group, serum CD5L levels of asthmatic mice were significantly decreased, and the levels of CD5L in lung tissues and bronchoalveolar lavage fluid (BALF) were significantly increased. CD5L reduced airway inflammation and Th2 immune responses in asthmatic mice. CD5L exerted its anti-inflammatory function by increasing CD11chigh alveolar macrophages (CD11chigh AMs), and the anti-inflammatory role of CD11chigh AMs in allergic asthma was confirmed by CD11chigh AMs depletion and transfer assays. In addition, CD5L increased the CD5L+ macrophages and inhibited NLRP3 inflammasome activation by increasing HDAC2 expression in lung tissues of asthmatic mice. Hence, our study implicates that CD5L has potential usefulness for asthma treatment.

Effects of human adipose tissue- and bone marrow-derived mesenchymal stem cells on airway inflammation and remodeling in a murine model of chronic asthma

It is challenging to overcome difficult-to-treat asthma, and cell-based therapies are attracting increasing interest. We assessed the effects of mesenchymal stem cell (MSC) treatments using a murine model of chronic ovalbumin (OVA)-challenged asthma. We developed a murine model of chronic allergic asthma using OVA sensitization and challenge. Human adipose-derived MSCs (hADSCs) or human bone marrow-derived MSCs (hBMSCs) were administered. We measured the levels of resistin-like molecule-β (RELM-β). We also measured RELM-β in asthma patients and normal controls. OVA-challenged mice exhibited increased airway hyper-responsiveness, inflammation, and remodeling. hBMSC treatment remarkably decreased airway hyper-responsiveness but hADSC treatment did not. Both MSCs alleviated airway inflammation, but hBMSCs tended to have a more significant effect. hBMSC treatment reduced Th2-cytokine levels but hADSC treatment did not. Both treatments reduced airway remodeling. The RELM-β level decreased in the OVA-challenged control group, but increased in both treatment groups. We found that the serum level of RELM-β was lower in asthma patients than controls. MSC treatments alleviated the airway inflammation, hyper-responsiveness, and remodeling associated with chronic asthma. hBMSCs were more effective than hADSCs. The RELM-β levels increased in both treatment groups; the RELM-β level may serve as a biomarker of MSC treatment efficacy.

Activation of NLRP3 inflammasome contributes to the inflammatory response to allergic rhinitis via macrophage pyroptosis

ObjectiveAllergic rhinitis (AR) is a heterogeneous disease and its pathogenesis is still unclear. Growing clinical evidence has thrown light on the key role of NOD-like Receptor Family Pyrin Domain Containing 3 (NLRP3) inflammasome activation of allergic disease. However, the effect of NLRP3 activation in macrophages for AR has not been elucidated. This study aims to investigate the role of NLRP3 in ovalbumin (OVA)-stimulated bone marrow-derived macrophages (BMDMs) and to confirm the impact of macrophage pyroptosis in allergic rhinitis. MethodsNasal inflammation levels were assessed by H&E and dual immunofluorescence staining. BMDMs were cultured and were stimulated with OVA in the presence or absence of MCC950 to further investigate the effect of NLRP3 activation in macrophages. The cell lysates and supernatants were harvested to measure NLRP3 and downstream molecules, as well as cell rupture, and IL-1β production. Besides, an OVA-exposed AR mouse model was developed, and the histopathology in nasal mucosa, and the relationship between macrophage pyroptosis and local inflammation were detected. The inhibitory role of MCC950 was also evaluated. ResultsThe present results uncovered that the number of macrophages and NLRP3 expression were increased in the nasal mucosa of AR subjects, and upregulation of macrophage pyroptosis contributed to local allergic inflammation. In addition, the OVA challenge induced NLRP3 inflammasome activation in BMDMs, as evidenced by enhanced expressions of NLRP3-ASC-caspase-1 inflammasome, gasdermin D, production of IL-1β, and increased macrophage lysis. Furthermore, inhibition of NLRP3 inflammasome attenuated nasal inflammation, accompanied by a reduced number of inflammatory cells and lower levels of IL-1β and OVA-specific IgE. ConclusionsOur results indicate that NLRP3 inflammasome played an important role in allergic airway inflammation by activating macrophage’s pyroptotic cell death and releasing inflammatory mediators to local tissues. Inhibition of NLRP3 inflammasome-mediated pyroptosis could be a promising therapeutic strategy for ameliorating inflammatory responses in allergic rhinitis.

Functional and morphologic dysfunctions in the airways of rats submitted to an experimental model of obesity-exacerbated asthma

The obesity-exacerbated asthma phenotype is characterized by more severe asthma symptoms and glucocorticoid resistance. The aim of this study was to standardize an obesity-exacerbated asthma model by a high glycemic level index (HGLI) diet and ovalbumin (OVA) sensitization and challenges in Wistar rats. Animals were divided into groups: control (Ctrl), obese (Ob), asthmatic (Asth), obese asthmatic (Ob + Asth) and obese asthmatic treated with dexamethasone (Ob + Asth + Dexa), and in vivo and in vitro functional and morphological parameters were measured. After HGLI consumption, there was an increase in body weight, fasting blood glucose, abdominal circumferences, body mass index and adiposity index. Respiratory function showed a reduction in pulmonary tidal volume and ventilation. In isolated tracheas, carbachol showed an increase in contractile efficacy in the Ob, Ob + Asth and Ob + Asth + Dexa, but mostly on Ob + Asth. Histological analysis of lungs showed peribronchovascular inflammation and smooth muscle hypertrophy and extracellular remodeling on Ob + Asth and Ob + Asth + Dexa. An obesity-exacerbated asthma model was successfully established. Therefore, this model allows further molecular investigations and the search for new therapies for the treatment and relief of symptoms of patients with obesity-induced resistant asthma.

KCa3.1 differentially regulates trachea and bronchi epithelial gene expression in a chronic-asthma mouse model.

Ion channels are potentially exploitable as pharmacological targets to treat asthma. This study evaluated the role of KCa3.1 channels, encoded by Kcnn4, in regulating the gene expression of mouse airway epithelium and the development of asthma traits. We used the ovalbumin (OVA) challenge as an asthma model in wild-type and Kcnn4-/- mice, performed histological analysis, and measured serum IgE to evaluate asthma traits. We analyzed gene expression of isolated epithelial cells of trachea or bronchi using mRNA sequencing and gene ontology and performed Ussing chamber experiments in mouse trachea to evaluate anion secretion. Gene expression of epithelial cells from mouse airways differed between trachea and bronchi, indicating regional differences in the inflammatory and transepithelial transport properties of proximal and distal airways. We found that Kcnn4 silencing reduced mast cell numbers, mucus, and collagen in the airways, and reduced the amount of epithelial anion secretion in the OVA-challenged animals. In addition, gene expression was differentially modified in the trachea and bronchi, with Kcnn4 genetic silencing significantly altering the expression of genes involved in the TNF pathway, supporting the potential of KCa3.1 as a therapeutic target for asthma.

Genetic deletion of osteoprotegerin attenuates asthma development through suppression of inflammatory response in mice

To clarify the detailed molecular mechanisms underlying the development of asthma, we assessed the potential immune effects of prenatal osteoprotegerin (OPG) inhibition in the pathogenesis of asthma. The effects of OPG deficiency on the development of asthma were evaluated using an ovalbumin-induced asthma model in OPG knockout mice. Histological analysis demonstrated that OPG was mainly detected in airway epithelial cells in wild type mice. After ovalbumin sensitization and challenge, accumulation of inflammatory cells, gene expression of T helper 2-related cytokines and mucus hypersecretion in lung tissues were inhibited by OPG deficiency. Importantly, the serum level of IgE was not increased in OPG KO mice after ovalbumin sensitization and challenge. Based on these findings, OPG knockout mice were protected against methacholine-induced airway hyperresponsiveness. OPG expression is thought to be essential for induction of the allergic immune response in asthma.

Therapeutic Effects of Human Pluripotent Stem Cell-Derived Mesenchymal Stem Cells on a Murine Model of Acute Type-2-Dominated Airway Inflammation

Allergic rhinitis and allergic asthma are the most common type-2 inflammatory diseases, which are hardly curable and cause heavy burden to general well-being. Mesenchymal stem cells (MSCs) are multipotent nonhematopoietic cells with potential immunomodulatory effects that have been showning to have a therapeutic effect on allergic diseases. Here, we investigated the effects of human induced pluripotent stem cell (iPSC)-derived MSCs on airway hyperresponsiveness and acute type-2-dominated inflammation throughout the upper and lower airways. In this study, human MSCs, MSC cell culture supernatant, and culture medium (control) was injected into the acute airway inflammatory model via the tail vein. Mouse behavioristics were recorded immediately and mouse lung function was measured 24hours after the last ovalbumin (OVA) challenge. Histological staining, Luminex, Elisa and flow cytometry were employed to evaluate the effects on the production of total/OVA-specific IgG1 and IgE, cytokines expression in lung tissues, and inflammatory cells infiltration in the lung and spleen of the experimental mice. Expressions of eotaxin, IL-4, IL-5, IL-13, IL-33 in nasal and lung lavage were evaluated by Luminex and Elisa. We found that for this acute inflammatory mouse model, human MSC transplantation significantly mitigated the decreased motoring time and the increased lung function Rrs caused by OVA challenge. Serum OVA-IgG1, OVA-IgE, and eosinophil percentages in the splenocytes were significantly decreased. Injection of the MSC supernatant also showed the same trend, but not significantly changed. After treatment, IL-4 and IL-13 were significantly decreased in the lung tissue, and IL-5 and IL-13 were significantly decreased in lung lavage. In conclusion, both human MSC culture supernatant and cell transplantation could alleviate AHR and inflammation in acute inflammatory experimental animals, which demonstrated their potential for clinical therapeutics. Human iPSC-MSCs, MSC cell culture supernatant, or culture medium (control) was injected into the OVA-induced acute airway inflammatory model via the tail vein. Behavioral changes, AHR, serum OVA-specific IgG1 and IgE concentrations, and type-2 inflammations were alleviated.

Activation of Free Fatty Acid Receptor 4 (FFA4) Ameliorates Ovalbumin-Induced Allergic Asthma by Suppressing Activation of Dendritic and Mast Cells in Mice.

Epidemiological and clinical studies have suggested that intake of n-3 polyunsaturated fatty acids (PUFA) reduces the incidence of allergic airway diseases and improves pulmonary function in patients with allergic asthma. However, the pharmacological targets of PUFA have not been elucidated upon. We investigated whether free fatty acid receptor 4 (FFA4, also known as GPR120) is a molecular target for beneficial PUFA in asthma therapy. In an ovalbumin (OVA)-induced allergic asthma model, compound A (a selective agonist of FFA4) was administrated before OVA sensitization or OVA challenge in FFA4 wild-type (WT) and knock-out (KO) mice. Compound A treatment of RBL-2H3 cells suppressed mast cell degranulation in vitro in a concentration-dependent manner. Administration of compound A suppressed in vivo allergic characteristics in bronchoalveolar lavage fluid (BALF) and lungs, such as inflammatory cytokine levels and eosinophil accumulation in BALF, inflammation and mucin secretion in the lungs. Compound A-induced suppression was not only observed in mice treated with compound A before OVA challenge, but in mice treated before OVA sensitization as well, implying that compound A acts on mast cells as well as dendritic cells. Furthermore, this suppression by compound A was only observed in FFA4-WT mice and was absent in FFA4-KO mice, implying that compound A action is mediated through FFA4. Activation of FFA4 may be a therapeutic target of PUFA in allergic asthma by suppressing the activation of dendritic cells and mast cells, suggesting that highly potent specific agonists of FFA4 could be a novel therapy for allergic asthma.

Allergen specific immunotherapy with plasmid DNA encoding OVA-immunodominant T cell epitope fused to Tregitope in a murine model of allergy

BackgroundPeptide-based immunotherapy (PIT) was introduced as an attractive approach in allergen-specific immunotherapy (AIT). However, PIT clinical trials have shown variable results, and immune response to peptides is not precisely predictable. On the other hand, induction of antigen-specific tolerance may be augmented when allergens are combined with the regulatory T cell epitope (Tregitope). This study aimed to evaluate the therapeutic administration of a plasmid DNA encoding Tregitope and ovalbumin (OVA) immunodominant epitope in the murine model of allergy. MethodsFollowing the induction of allergic rhinitis by ovalbumin, vaccinated group received three doses of recombinant plasmid containing Signal peptide-Tregitope-OVA T cell epitope. After the final OVA challenge, clinical symptoms, histopathological changes, OVA-specific IgE level, and cytokine secretion pattern of spleen cells were examined. ResultsOur data are showing that AIT with the recombinant DNA vaccine significantly suppressed airway inflammation; reduced eosinophilic infiltration in the nasal mucosa; decreased expression level of IL-4 and IL-17 in spleen cells, while IFN-γ, IL-10, and TGF-β expression were increased. Moreover, OVA-specific IgE levels were also decreased. ConclusionThese results suggest that Tregitope-immunodominant T cell epitope fusion can act as a safe and effective approach in DNA-based allergen-specific immunotherapy.

In vivo visualization and analysis of ciliary motion in allergic rhinitis models induced by ovalbumin.

Due to the lack of an assessment approach, the image of in vivo nasal ciliary motion of allergic rhinitis (AR) has never been captured and analyzed to date. Here, we have used an optimized approach to analyze the nasal ciliary function in vivo in AR rats. The digital microscopy system, a method for direct observation of ciliary motion in a living AR rat model, was applied to visualize and measure ciliary motion in vivo, including ciliary beat frequency (CBF) and ciliary beat distance (CBD). The AR rat model was established by ovalbumin sensitization. Comparisons of nasal ciliary motion in vivo between the experimental group (ovalbumin sensitization, allergen, or histamine) and the control group were analyzed. In the living rat model of allergic rhinitis, CBF and CBD decreased to 57.8 and 73.1% of the control group, respectively, but were restored after administration of chlorpheniramine maleate. Ovalbumin (OVA) significantly inhibited the ciliary motion of normal mucosa in vivo. However, responding to the OVA challenge, the ciliary motion of OVA-sensitized mucosa would not decrease further and stay at a stable level. Histamine stimulated in vivo ciliary motion quickly within 30 min, but afterward, the ciliary motion gradually decreased below the baseline. These results have clarified that in vivo ciliary motion was impaired by nasal mucosal sensitization, and this impairment was most likely related to allergen challenge and histamine. In addition, the short-term stimulation and long-term inhibition effects of histamine on in vivo ciliary motion were first reported in this study.

Interleukin-10 enhances IL-33-mediated MC activation and modulates the development of food allergy

Abstract We recently demonstrated an unexpected, proinflammatory role for the pleiotropic cytokine, IL-10, in promoting mast cell (MC) responses during food allergy. IL-10 enhanced MC proliferation and survival and promoted IgE-dependent responses to enteric ovalbumin (OVA) challenge. However, whether the effects of IL-10 on MCs extend beyond IgE-mediated signaling is not clear. To determine whether IL-10 can prime MC activation mediated by IgE-independent stimuli, we assessed the effects of rIL-10 on IL-33-stimulated bone marrow-derived MCs (BMMCs) and examined the development of food allergy in IL-10-depleted ST2−/− mice. IL-10 co-culture significantly enhanced the activity and cytokine production of both IgE and IL-33-activated MCs. Furthermore, the production of MC-derived cytokines such as IL-13 was suppressed in IL-33-stimulated IL-10−/− BMMCs, which could be restored by addition of exogenous IL-10. IL-10 enhanced MC FcɛRI and ST2 expression. Further, ST2−/− BMMCs demonstrated that IL-10 enhanced IgE-mediated activation in the absence of autocrine IL-33 signaling. To assess the role of IL-10 in vivo, food allergy was measured in WT and ST2−/− mice subjected to antibody-mediated IL-10 depletion. IL-10-depleted WT mice exhibited a significant attenuation in allergic diarrhea and MC-mediated responses to OVA challenge. Similarly, ST2−/− mice also exhibited a profound suppression of MC-mediated responses, demonstrating the importance of IL-33 in MC regulation. IL-10 depletion had no additional effects in ST2−/− mice. However, IL-10/ST2−/− mice exhibited a further decrease in OVA-IgE and MC activation compared to ST2−/− mice. Our data reveal a novel role for IL-10 in enhancing both IgE and IL-33-mediated MC responses. This project was supported by funds from the National Institutes of Health grants: NIAID R15AI107668 (CBM)

Dioscin exhibits protective effects on in vivo and in vitro asthma models via suppressing TGF-β1/Smad2/3 and AKT pathways.

Dioscin is a natural product that possesses protective effects on multiple chronic injuries, but its effects on asthma are not fully understood. Herein, we evaluated its effects on asthmatic mice established by ovalbumin (OVA) sensitization and challenges and further explored the mechanism. Inflammatory cells in bronchoalveolar lavage fluids (BALFs) were analyzed using Diff-Quik staining. OVA-specific immunoglobulin E (IgE)/IgG1in serum and inflammatory cytokines (interleukin 4[IL-4], IL-5, IL-13, and tumor necrosis factor-α) in BALFs and lung tissues were measured using Enzyme-Linked Immunosorbent Assay Kits. Hematoxylin and eosin, periodic acid-Schiff, and immunohistochemistry staining showedhistopathological changes in lung tissues. Epithelial-mesenchymal transition (EMT) in human bronchial epithelial (16HBE) cells was assessed by immunofluorescence staining. Hydroxyproline content was used to evaluate collagen deposition. Polymerase chain reaction and Western blot were performed to measure messenger RNA and protein expression. We found that dioscin treatment (particularly at the dose of 80 mg/kg) significantly inhibited pulmonary inflammation in asthmatic mice, as evidenced by the decreased serum OVA-specific IgE/IgG1 and the reduced inflammatory cells and cytokines in BALFs and lung tissues. Moreover, dioscin effectively ameliorated the goblet cell hyperplasia, mucus hypersecretion, collagen deposition, and smooth muscle hyperplasia in the airways of asthmatic mice. Mechanistically, dioscin restrained the activated TGF-β1/Smad2/3 and protein kinase B(AKT) signal pathways in lung tissues and potently reversed the TGF-β1-induced EMT and phosphorylation of Smad2/3 and AKT in 16HBE cells. Collectively, dioscin displayed protective effects on OVA-induced asthmatic mice via adjusting TGF-β1/Smad2/3 and AKT signal pathways, supporting the fact that dioscin could be a candidate for chronic asthma prevention in the future.

Immunomodulatory effect and histological alteration of thermally oxidized sunflower oil in male Wistar rats

Many foods are prepared by deep-frying as this provides unique flavors/textures that improve overall palatability to consumers. Sunflower oil is one of the most widely-used frying oils in the world. However, during frying, fats in the foodstuff are heated to > 150° C and concurrently come into contact with agents found in the air, water, and other foods being cooked at the same time. Since long-term consumption of oxidized/oxidation products can contribute to the development of a variety of pathologies. Used cooking oil has become of increased concern to both health administrators and consumers. Few studies have sought to examine potential immunomodulatory effects from exposures to sunflower oil or its oxidized/oxidation products. To address this gap in knowledge, here, sunflower oil was used to fry potatoes at 190° C, every 30 min; a new 100 g batch of slices was cooked. Frying was performed continuously for 5h/day for 2 and 4 days (10 and 20 h total), and then the parental uncooked oil and each of the used oils were provided to Wistar rats in their diet (at 20% level) for a total of 10 weeks. Measures of body weight\food intake indicated that diets containing the used oils led to slightly reduced food intakes and host weights. Kidney weights were not affected by consumption of the two used oils, but the liver was enlarged in rats fed with the oil treated for 20 h. Evaluation of key lipid-serum parameters, i.e., total cholesterol, HDL cholesterol, and triglycerides, revealed a diet-related decrease in each; oxidized fats reduce their concentration compared to fresh fats. Conversely, serum LDL cholesterol levels were increased. Histological analyses indicated that consumption of the oxidized oils caused both kidney (e.g., tubular/glomerular dilation, vascular congestion, inflammation, tubular necrosis) and liver (e.g., vascular congestion, inflammation, necrosis) damages. Assessments of host immune function, i.e., ability to form antibody to ovalbumin (OVA) challenge, indicated that in rats fed the used oil, there were significant decreases in serum anti-OVA antibody levels. This suggested that host immunocompetence could be compromised as a result of long-term consumption of a diet containing a relatively high (i.e., 20%) content of used sunflower oils.

Magnesium isoglycyrrhizinate alleviate airway inflammatory responses in ovalbumin-induced mouse model of allergic asthma

Objective Asthma is a common chronic airway inflammatory disease, lacking effective therapeutic approaches. Magnesium isoglycyrrhizinate (MgIG) is an anti-inflammatory drug for treating chronic inflammation. However, it is still ambiguous whether MgIG can function in allergy induced asthma. In this study, we investigated the anti-inflammation effect of MgIG in mice with allergy induced asthma and explored the underlying mechanisms. Methods Mouse asthma model was established with ovalbumin (OVA) sensitization and challenge. Subsequently, mice sensitized with OVA were randomly assigned into fourgroups: asthma model group (MDL), dexamethasone group (DXM), MgIG group (MgIG), and normal mice were used as normal control (CON). The mice in MgIG, MDL were given 0.2 mg/mL MgIG solution by atomization inhalation for 30 min before 1% (w/v) OVA challenge. At the completion of model establishment and drug treatment, cells in bronchoalveolar lavage fluid were classified, inflammatory factors in serum were determined, histopathological analysis was performed by H&E staining, and expression of MUC5AC, NLRP3, and cleaved caspase-1 in the lung tissue was also determined by immunohistochemistry and western blotting, respectively. Key findings In comparison to MDL group, MgIG treatment could significantly inhibit the recruitment of white blood cells, neutrophils, and eosinophils in BALF, reduced the production of IL-6, TNF-α, and IgE in serum, and reduced mucus secretion and the infiltration of inflammatory cells. Also, an increase of NLRP3 and Caspase-1 protein levels were suppressed by MgIG treatment. Conclusion Our study findings support that nebulizer inhalation of MgIG as an effective therapy in treating the allergy induced asthma.

Synergistic effect of roflumilast with dexamethasone in a neutrophilic asthma mouse model.

Asthma is a chronic airway inflammatory disease with heterogeneous features. Most cases of asthma are steroid sensitive, but 5%-10% are unresponsive to steroids, leading to challenges in treatment. Neutrophilic asthma is steroid-resistant and characterized by the absence or suppression of the T-helper type II (TH 2) process and an increase in the TH 1 and/or TH 17 process. Roflumilast (ROF) has anti-inflammatory effects and has been used to treat chronic inflammatory airway diseases, such as chronic pulmonary obstructive disease. It is unclear whether ROF may have a therapeutic role in neutrophilic asthma. In this study, we investigated the synergistic effect of ROF with dexamethasone (DEX) in a neutrophilic asthma mouse model. C57BL/6 female mice sensitized to ovalbumin (OVA) were exposed to five intranasal OVA treatments and three intranasal lipopolysaccharide (LPS) treatments for an additional 10days. During the intranasal OVA challenge, ROF was administrated orally, and DEX was injected intraperitoneally. Protein, pro-inflammatory cytokines, inflammatory cytokines and other suspected markers were identified by enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and western blot. Following exposure to LPS in OVA-induced asthmatic mice, neutrophil predominant airway inflammation rather than eosinophil predominant inflammation was observed, with increases in airway hyperresponsiveness (AHR). The lungs of animals treated with ROF exhibited less airway inflammation and hyperresponsiveness. To investigate the mechanism underlying this effect, we examined the expression of proinflammatory cytokines suspected to be involved in inflammatory cytokines and proteins. Roflumilast reduced total protein in bronchioalveolar lavage fluid; levels of interleukin (IL)-17A, IL-1β messenger RNA, interferon γ and tumour necrosis factor α; and recovered histone deacetylase-2 (HDAC2) activity. Combination therapy with ROF and DEX further reduced the levels of IL-17, IL-22 and IL-1β mRNA and proinflammatory cytokines. The combination of ROF and DEX reduced lung inflammation and AHR much more than one of them alone. Roflumilast reduces AHR and lung inflammation in the neutrophilic asthma mouse model. Furthermore, additive effects were observed when DEX was added to ROF treatment, possibly because of recovery of HDAC2/β-actin activity. This study demonstrates the anti-inflammatory properties of ROF in a neutrophilic asthma mouse model.

The anti-inflammatory effect of dapsone on ovalbumin-induced allergic rhinitis in balb/c mice

AimsAllergic rhinitis (AR), a major chronic inflammatory disease of the respiratory system, is a public health issue because of its substantial negative impact on quality of life and work efficiency alongside its high prevalence and costs. Dapsone is a sulfone chemical with reported anti-inflammatory and antibacterial properties. Accordingly, we investigated the anti-inflammatory impact of dapsone on ovalbumin-induced allergic rhinitis in balb/c mice. Main methodsIntraperitoneal ovalbumin and hydroxide aluminum injection followed by intranasal ovalbumin administration sensitized female Balb/c mice. Mice received intraperitoneal dapsone either acute (5, 10, 20 mg/kg) 30 min before the last ovalbumin challenge, or chronic (20 mg/kg) on days 21 to 35. Key findingsBoth acute and chronic intraperitoneal usage of dapsone showed a considerable decrease in the nasal scratching behavior, the number of sneezing, serum IL-4 and IgE levels of ovalbumin-induced AR in balb/c mice, but there was a significant increase in serum IFNγ level. Histopathological analysis demonstrated a significant reduction of eosinophil numbers, following dapsone injection. Goblet cell hyperplasia and respiratory epithelial-thickness decreased significantly in the acute and chronic 20 mg/kg dapsone groups compared to the ovalbumin-induced controls. SignificanceThis study shows that there is an association between acute and chronic dapsone treatment and some anti-allergic effects through an inflammation cascade.

The STAT6 inhibitor AS1517499 reduces the risk of asthma in mice with 2,4-dinitrochlorobenzene-induced atopic dermatitis by blocking the STAT6 signaling pathway

BackgroundEpidemiological studies have revealed a link between atopic dermatitis (AD) and asthma. AS1517499, a selective signal transducer and activation of transcription 6 (STAT6) inhibitor, has been shown to effectively block this connection. In this study, we further explored the underlying mechanism by constructing an AD mouse model.MethodsFemale BALB/c mice were randomly divided into four groups (n = 10/group). The AD mouse model was established by 2,4-dinitrochlorobenzene induction with repeated ovalbumin challenge. AS1517499 and corn oil were used as treatment interventions. The features of airway inflammation, remodeling, and hyperactivity were analyzed.ResultsActive use of AS1517499 in AD mice effectively reduced Th2-related cytokine levels, alleviated airway eosinophil and lymphocyte infiltration, and regulated GATA3/Foxp3 levels and subepithelial collagen deposition. These changes might be due to specific blockade of the STAT6 signaling pathway.ConclusionAS1517499 could partially block the association between AD and asthma by specifically inhibiting the STAT6 signaling pathway.

Anxiety-like behavior induced by allergen is associated with decreased irregularity of breathing pattern in rats

Allergic rhinitis (AR) is a chronic inflammatory disorder associated with a high prevalence of anxiety symptoms and respiratory disorders that adversely affect the quality of life. Studies have shown that allergen exposure induces anxiety-like behaviors. On the other hand, stress impairs the breathing pattern. However, the effect of stress on respiration and the relationship between anxiety-like behavior and stress-induced changes in breathing pattern has not been evaluated in AR. We assessed the impact of ovalbumin (OVA)-induced anxiety-like behaviors on stress-induced breathing pattern changes. Our findings showed that the allergic rhinitis induced by OVA challenge in sensitized rats induces anxiety-like behavior. Also, we found that stress decreases respiratory irregularity and increases respiratory variability, as well as the synchronization between IBI and RV time-series in AR animals. Moreover, in AR animals, we found a significant positive correlation between anxiety-like behavior and respiratory irregularity under non-stress conditions. Besides, a significant negative correlation was observed under stress conditions. The findings showed that anxiety-related behaviors may contribute to respiratory impairments under stress conditions in AR.

Dexmedetomidine alleviates airway hyperresponsiveness and allergic airway inflammation through the TLR4/NF‑κB signaling pathway in mice.

Dexmedetomidine (DEX) suppresses inflammatory responses and protects against organ injury. The aim of the present study was to investigate the effect of DEX on airway hyperresponsiveness (AHR) and allergic airway inflammation, as well as its underlying mechanism of action in a murine model of ovalbumin (OVA)-induced asthma. A total of 30 female BALB/c mice were divided into 6 groups (n=5 mice/group): Control, OVA, OVA + DEX (20, 30 or 50 µg/kg) and OVA + TAK-242 [a toll-like receptor 4 (TLR4) inhibitor]. The mice were intraperitoneally injected with 20, 30 or 50 µg/kg DEX 1 h before OVA challenge. AHR to inhaled methacholine (Mch) was measured, and the mice were sacrificed 24 h after the last challenge. AHR following Mch inhalation was measured using the FlexiVent apparatus. Hematoxylin and eosin, periodic acid-Schiff and Wright-Giemsa staining was performed to evaluate inflammatory cell infiltration in the lung tissue. The levels of IL-4, IL-5 and IL-13 in the bronchoalveolar lavage fluid were analyzed using ELISA, and their mRNA expression levels in the lung tissue were examined using reverse transcription-quantitative PCR. The protein expression of TLR4, NF-κB and phosphorylated (p)NF-κB in the lung tissue was also detected using immunohistochemistry. In the murine OVA-induced asthma model, DEX decreased AHR following Mch inhalation and reduced the infiltration of inflammatory cells. IL-4, IL-5 and IL-13 levels in the bronchoalveolar lavage fluid were significantly lower following DEX treatment. Furthermore, DEX treatment inhibited the expression of TLR4, NF-κB and p-NF-κB in the lung tissue and exhibited a similar effect to TAK-242 treatment. In conclusion, DEX may attenuate AHR and allergic airway inflammation by inhibiting the TLR4/NF-κB pathway. These results suggested that DEX may represent a potential anti-inflammatory agent for the treatment and management of patients with asthma.

Has2 Regulates the Development of Ovalbumin-Induced Airway Remodeling and Steroid Insensitivity in Mice.

HAS2 is a member of the gene family encoding the hyaluronan synthase 2, which can generate high-molecular-weight hyaluronan (HMW-HA). Our previous study identified HAS2 as a candidate gene for increased susceptibility to adult asthma. However, whether HAS2 dysfunction affects airway remodeling and steroid insensitivity is still limited. Therefore, this study aimed to clarify the Has2 dysfunction, triggering severe airway remodeling and steroid insensitivity in a murine model of asthma. Has2 heterozygous-deficient (Has2 +/−) mice and their wild-type littermates have been evaluated in a model of chronic ovalbumin (OVA) sensitization and challenge. Mice present a higher sensitivity to OVA and higher IL-17 release as well as eosinophilic infiltration. RNA sequencing demonstrated the downregulation of EIF2 signaling pathways, TGF-β signaling pathways, and heat shock proteins with Th17 bias in Has2 +/−-OVA mice. The combined treatment with anti-IL-17A antibody and dexamethasone reduces steroid insensitivity in Has2 +/−-OVA mice. Has2 attenuation worsens eosinophilic airway inflammation, airway remodeling, and steroid insensitivity. These data highlight that HAS2 and HMW-HA are important for controlling intractable eosinophilic airway inflammation and remodeling and could potentially be exploited for their therapeutic benefits in patients with asthma.