Ovalbumin-induced Airway Inflammation Research Articles

Selaginella uncinata flavonoids ameliorated ovalbumin-induced airway inflammation in a rat model of asthma

Ethnopharmacological relevanceSelaginella uncinata (Desv.) Spring, known as “Cuiyuncao”, is a perennial herb widely distributed in the Southeast Asian countries. In the folk medicine, the local minority commonly use it to treat cough and asthma for centuries. Aim of the studyThis study was carried out to investigate the protective mechanisms of total flavonoids from S. uncinata (SUF) on airway hyperresponsiveness, cytokine release and bitter taste receptors (T2Rs) signaling with emphasis on inflammatory responses in a rat model of ovalbumin (OVA)-induced asthma. Materials and methodsRats were sensitized and challenged with OVA to induce typical asthmatic reactions. Pathological changes of lung tissue were examined by HE staining. The serum levels of T cell-associated cytokines (IFN-γ, IL-4, IL-5 and IL-13), total IgE and OVA-specific IgE were determined by enzyme-linked immunosorbent assay (ELISA). Gene expressions of T2R10, IP3R1 and Orai1 in lung tissue were assayed by fluorescence quantitative real-time polymerase chain reaction (FQ-PCR) while protein expressions of NFAT1 and c-Myc were assayed by western blot analysis. The activation of SUF was investigated on tansgentic T2R10-GFP HEK293 cells. ResultsSUF treatment attenuated airway hyperresponsiveness and goblet cell hyperplasia compared with OVA-challenged asthmatic rats. The serum levels of IL-4, IL-5 and IL-13 as well as total and OVA-specific IgE were decreased while serum IFN-γ was increased in SUF-treated rats. SUF treatment significantly up-regulated T2R10 gene expression, down-regulated IP3R1 and Orai1 gene expression. SUF further suppressed eotaxin, NFAT1 and c-Myc protein expression in lung tissues of OVA-challenged rats. ConclusionsThese results imply that SUF exerts anti-inflammatory function through the T2R10/IP3R1/NFAT1 dependent signaling pathway, and may warrant further evaluation as a possible agent for the treatment of asthma.

Secretoglobin Superfamily Protein SCGB3A2 Alleviates House Dust Mite-Induced Allergic Airway Inflammation in Mice

Background: Secretoglobin (SCGB) 3A2, a novel, lung-enriched, cytokine-like, secreted protein of small molecular weight, was demonstrated to exhibit various biological functions including anti-inflammatory, antifibrotic and growth-factor activities. Anti-inflammatory activity was uncovered using the ovalbumin-induced allergic airway inflammation model. However, further validation of this activity using knockout mice in a different allergic inflammation model is necessary in order to establish the antiallergic inflammatory role for this protein. Methods:Scgb3a2-null (Scgb3a2^-/-) mice were subjected to nasal inhalation of Dermatophagoides pteronyssinus extract for 5 days/week for 5 consecutive weeks; control mice received nasal inhalation of saline as a comparator. Airway inflammation was assessed by histological analysis, the number of inflammatory cells and various Th2-type cytokine levels in the lungs and bronchoalveolar lavage fluids by qRT-PCR and ELISA, respectively. Results: Exacerbated inflammation was found in the airway of Scgb3a2^-/- mice subjected to house dust mite (HDM)-induced allergic airway inflammation compared with saline-treated control groups. All the inflammation end points were increased in the Scgb3a2^-/- mice. The Ccr4 and Ccl17 mRNA levels were higher in HDM-treated lungs of Scgb3a2^-/- mice than wild-type mice or saline-treated Scgb3a2^-/- mice, whereas no changes were observed for Ccr3 and Ccl11 mRNA levels. Conclusions: These results demonstrate that SCGB3A2 has an anti-inflammatory activity in the HDM-induced allergic airway inflammation model, in which SCGB3A2 may modulate the CCR4-CCL17 pathway. SCGB3A2 may provide a useful tool to treat allergic airway inflammation, and further studies on the levels and function of SCGB3A2 in asthmatic patients are warranted.

Investigation of anti-asthmatic potential of Kanakasava in ovalbumin-induced bronchial asthma and airway inflammation in rats

Ethno-pharmacological relevanceKanakasava is an Indian traditional Ayurvedic formulation containing Datura (Datura metel), Vasaca (Adhatoda vasica), Dhataki (Woodfordia fruticosa) and Grape (Vitis vinifera) extracts as major constituents and used to treat pulmonary diseases including coughing, breathing difficulty and asthma. The present study was designed to assess the safety and therapeutic efficacy of Kanakasava against ovalbumin-induced bronchial asthma and related airway inflammation in rats due to lack of evidence based therapeutic efficacy data. Material and methodsMale wistar rats were sensitized with allergen (ovalbumin, 40mg/rat+aluminum hydroxide, 2.0mg/rat) and treated orally with standard dexamethasone (2.5mg/kg, b.w.) or Kanakasava (1.23 and 2.46ml/kg, b.w.) from day 1 to day 28. Inflammatory markers, including cell counts and cytokines such as interleukins (IL-4, IL-5, IL-1β), tumor necrosis factor (TNF-α), leukotriene (LTD-4), immunoglobulin (IgE), nitric oxide and nitrite levels in both blood and broncheo alveolar lavaged fluid (BALF) were analyzed. Abdominal mesentery was studied histologically for mast cell degranulation, whereas lung functions were investigated by spirometer. Method was also developed to quantify gallic acid and ethyl gallate content in Kanakasava by HPTLC for its quality control. ResultsNone of the rats exhibited mortality and Kanakasava was found to be safe at the tested doses. Treatment with Kanakasava significantly (P<0.01) reversed elevated levels of IgE, cytokines, nitrites and influx of eosinophils and neutrophils in blood and BALF. These findings were further supported by the significant improvement in lung functions (P<0.01) and suppression (P<0.01) of degranulation of mast cells. The content of gallic acid and ethyl gallate in Kanakasava was found to be 1.94% and 0.98%, respectively. ConclusionThese findings demonstrated the preventive effect of Kanakasava in allergen induced model of asthma providing scientific basis for its traditional use in Ayurveda, since long time.

Endosomal recognition of Lactococcus lactis G121 and its RNA by dendritic cells is key to its allergy-protective effects

Bacterial cowshed isolates are allergy protective in mice; however, the underlying mechanisms are largely unknown. We examined the ability of Lactococcus lactis G121 to prevent allergic inflammatory reactions. We sought to identify the ligands and pattern recognition receptors through which L lactis G121 confers allergy protection. L lactis G121-induced cytokine release and surface expression of costimulatory molecules by untreated or inhibitor-treated (bafilomycin and cytochalasin D) human monocyte-derived dendritic cells (moDCs), bone marrow-derived mouse dendritic cells (BMDCs), and moDC/naive CD4+ T-cell cocultures were analyzed by using ELISA and flow cytometry. The pathology of ovalbumin-induced acute allergic airway inflammation after adoptive transfer of BMDCs was examined by means of microscopy. L lactis G121-treated murine BMDCs and human moDCs released TH1-polarizing cytokines and induced TH1 Tcells. Inhibiting phagocytosis and endosomal acidification in BMDCs or moDCs impaired the release of TH1-polarizing cytokines, costimulatory molecule expression, and T-cell activation on L lactis G121 challenge. Invivo allergy protection mediated by L lactis G121 was dependent on endosomal acidification in dendritic cells (DCs). Toll-like receptor (Tlr) 13-/- BMDCs showed a weak response to L lactis G121 and were unresponsive to its RNA. The TH1-polarizing activity of L lactis G121-treated human DCs was blocked by TLR8-specific inhibitors, mediated by L lactis G121 RNA, and synergistically enhanced by activation of nucleotide-binding oligomerization domain-containing protein (NOD) 2. Bacterial RNA is the main driver of L lactis G121-mediated protection against experimentally induced allergy and requires both bacterial uptake by DCs and endosomal acidification. In mice L lactis G121 RNA signals through TLR13; however, the most likely intracellular receptor in human subjects is TLR8.

Extracellular superoxide dismutase ameliorates house dust mite-induced atopic dermatitis-like skin inflammation and inhibits mast cell activation in mice.

Extracellular superoxide dismutase (EC-SOD) is an enzyme that catalyses the dismutation of superoxide anions. It has multiple functions, such as reactive oxygen species scavenging, anti-angiogenic, anti-inflammatory, antichemotatic and antitumor activities. Recently, we demonstrated that EC-SOD inhibits ovalbumin-induced allergic airway inflammation in mice. However, the anti-allergic effect of EC-SOD on skin tissue and the role of EC-SOD in mast cells, which are important for allergic responses, have not been well studied. In this study, we investigated whether EC-SOD can alleviate atopic dermatitis in mice and inhibit mast cell activation. Treatment with human recombinant EC-SOD ameliorated house dust mite-induced atopic dermatitis in mice. Furthermore, the levels of pro-allergic cytokine gene expression and histamine release increased in EC-SOD KO mast cells and decreased in EC-SOD overexpressing mast cells, suggesting that EC-SOD inhibits mast cell activation. Consistently, a passive cutaneous anaphylaxis experiment showed more blood leakage from EC-SOD KO mouse ear skin, implying that the lack of EC-SOD increases allergic responses. These results suggest that EC-SOD inhibits mast cell activation and atopic dermatitis and that the loss of EC-SOD causes more severe allergic responses, implying that EC-SOD might be a good drug candidate for treatment of allergic disorders, such as atopic dermatitis.

Phytochemical profiles and inhibitory effects of Tiger Milk mushroom (Lignosus rhinocerus) extract on ovalbumin-induced airway inflammation in a rodent model of asthma.

BackgroundLignosus rhinocerus (L. rhinocerus), which is known locally as Tiger Milk mushroom, is traditionally used in the treatment of asthma by indigenous communities in Malaysia. However, to date, its efficacy on asthma has not been confirmed by scientific studies and there is also sparse information available on its active constituents. In this study, the volatile constituent of L. rhinocerus hot water extract was investigated using gas chromatography mass spectrometry (GC-MS). The potential effects of L. rhinocerus extract for anti-asthmatic activity was further investigated on ovalbumin (OVA)-sensitized asthmatic Sprague Dawley rats.MethodsSequential extraction using five solvents (petroleum ether, diethyl ether, hexane, ethyl acetate and methanol) was conducted prior to GC-MS analysis. Male Sprague Dawley rats were divided into the following four groups of five animals each: 1) normal rats, 2) sensitization plus OVA-challenged rats 3) sensitization plus OVA-challenged with L. rhinocerus treatment and 4) sensitization plus OVA-challenged with dexamethasone treatment. The levels of immunoglobulin E (IgE) in the serum and T-helper 2 cytokines, including interleukin (IL)-4, IL-5 and IL-13, in bronchoalveolar lavage fluid (BALF), as well as eosinophil infiltration in the lungs, were investigated.ResultsGC-MS analysis revealed the presence of five main groups (alkane, fatty acids, benzene, phenol and dicarboxylic acid) with a total of 18 constituents. Linoleic acid (21.35 %), octadecane (11.82 %) and 2,3-dihydroxypropyl elaidate (10.47 %) were present in high amounts. The extract significantly ameliorated the increase in total IgE in serum and IL-4, IL-5 and IL-13 levels in BALF and also effectively suppressed eosinophils numbers in BALF while attenuating eosinophil infiltrations in the lungs.ConclusionL. rhinocerus hot water extract has the potential to be used as an alternative for the treatment of acute asthma.

Toxic and adjuvant effects of silica nanoparticles on ovalbumin-induced allergic airway inflammation in mice.

BackgroundSilica nanoparticles (SNPs) can easily enter in respiratory system via inhalation because of their low molecular weight and ease of dispersion. Toxicity and adverse effects of SNPs vary according to the physical characteristics of the particle.MethodsTo evaluate the toxic and adjuvant effects of 3 types of SNPs in the airway system, six-week-old female BALB/c mice were intranasally administered 3 types of SNPs (spherical [S-SNP], mesoporous [M-SNP], and polyethylene glycol-conjugated [P-SNP]) alone or SNPs/ovalbumin (OVA), three times weekly for 2 weeks. Airway hyper-responsiveness (AHR), bronchoalveolar lavage fluid (BALF), cytokine levels, and histology of the lungs were analyzed.ResultsThe S-SNPs/OVA group and M-SNPs/OVA group showed significant AHR, compared to the control group. Among all SNP-treated groups, the group administered SNPs/OVA showed greater inflammatory cell infiltration in BALF, extensive pathological changes, and higher cytokine levels (IL-5, IL-13, IL-1β, and IFN-γ) than those administered SNPs alone or saline/OVA.ConclusionExposure to SNPs alone and SNPs/OVA induced toxicity in the respiratory system. SNPs alone showed significant toxic effects on the airway system. Meanwhile, SNPs/OVA exerted adjuvant effects to OVA of inducing allergic airway inflammation. In particular, M-SNPs showed the most severe airway inflammation in both direct toxicity and adjuvant effect assays. P-SNPs induced less inflammation than the other types of SNPs in both models.

PLZF(+) Innate T Cells Support the TGF-β-Dependent Generation of Activated/Memory-Like Regulatory T Cells.

PLZF-expressing invariant natural killer T cells and CD4 T cells are unique subsets of innate T cells. Both are selected via thymocyte-thymocyte interaction, and they contribute to the generation of activated/memory-like CD4 and CD8 T cells in the thymus via the production of IL-4. Here, we investigated whether PLZF+ innate T cells also affect the development and function of Foxp3+ regulatory CD4 T cells. Flow cytometry analysis of the thymus and spleen from both CIITA transgenic C57BL/6 and wild-type BALB/c mice, which have abundant PLZF+ CD4 T cells and invariant natural killer T cells, respectively, revealed that Foxp3+ T cells in these mice exhibited a CD103+ activated/memory-like phenotype. The frequency of CD103+ regulatory T cells was considerably decreased in PLZF+ cell-deficient CIITATgPlzflu/lu and BALB/c.CD1d−/− mice as well as in an IL-4-deficient background, such as in CIITATgIL-4−/− and BALB/c.lL-4−/− mice, indicating that the acquisition of an activated/memory-like phenotype was dependent on PLZF+ innate T cells and IL-4. Using fetal thymic organ culture, we further demonstrated that IL-4 in concert with TGF-β enhanced the acquisition of the activated/memory-like phenotype of regulatory T cells. In functional aspects, the activated/memory-like phenotype of Treg cells was directly related to their suppressive function; regulatory T cells of CIITATgPIV−/− mice more efficiently suppressed ovalbumin-induced allergic airway inflammation compared with their counterparts from wild-type mice. All of these findings suggest that PLZF+ innate T cells also augmented the generation of activated/memory-like regulation via IL-4 production.

CXCR4 inhibitor attenuates ovalbumin-induced airway inflammation and hyperresponsiveness by inhibiting Th17 and Tc17 cell immune response.

Accumulating evidence suggests that chemokine (C-X-C motif) ligand 12 (CXCL12) and its receptor chemokine (C-X-C motif) receptor 4 (CXCR4) may contribute to the pathogenesis of allergic asthma. However, the underlying molecular mechanisms remain to be fully understood. T-helper 17 cells (Th17) and T-cytotoxic 17 cells (Tc17) have been implicated in the development of several allergic disorders, including asthma. The present study aimed to explore the association between CXCL12 signaling and Th17/Tc17 cells in the development of asthma. Ovalbumin (OVA)-sensitized BALB/c mice were treated with AMD3100, a specific CXCR4 antagonist, prior to OVA challenge. Following the final allergen (OVA) challenge, airway responsiveness to methacholine, influx of inflammatory cells to the airway, and cytokine levels in the bronchoalveolar lavage fluids (BALF) and lung homogenate were assessed. Interleukin (IL)-17-expressing CD3+CD8- lymphocytes (Th17 cells) and IL-17+CD3+CD8+ lymphocytes (Tc17 cells) isolated from lung tissue samples were detected by flow cytometry. The results of the present study demonstrated that administration of AMD3100 significantly decreased airway responsiveness to methacholine, attenuated the influx of inflammatory cells to the airway and reduced the levels of IL-4, IL-5 and IL-13 in the BALF. Furthermore, AMD3100 significantly reduced the increased number of lung Th17 and Tc17 cells as well as the levels of IL-17 in the lung homogenate induced by OVA challenge. In conclusion, the CXCR4 inhibitor suppresses the asthmatic response, which is associated with attenuation of the Th17 and Tc17 cell immune response.

Dietary Fiber Intake Regulates Intestinal Microflora and Inhibits Ovalbumin-Induced Allergic Airway Inflammation in a Mouse Model.

BackgroundRecently, academic studies suggest that global growth of airway allergic disease has a close association with dietary changes including reduced consumption of fiber. Therefore, appropriate dietary fiber supplementation might be potential to prevent airway allergic disease (AAD).ObjectiveWe investigated whether dietary fiber intake suppressed the induction of AAD and tried to elucidate the possible underlying mechanisms.MethodsThe control mice and AAD model mice fed with 4% standard-fiber chow, while low-fiber group of mice fed with a 1.75% low-fiber chow. The two fiber-intervened groups including mice, apart from a standard-fiber diet, were also intragastric (i.g.) administrated daily with poorly fermentable cellulose or readily fermentable pectin (0.4% of daily body weight), respectively. All animals except normal mice were sensitized and challenged with ovalbumin (OVA) to induce airway allergic inflammation. Hallmarks of AAD were examined by histological analysis and ELISA. The variation in intestinal bacterial composition was assessed by qualitative analysis of 16S ribosomal DNA (rDNA) content in fecal samples using real-time PCR.ResultsLow-fiber diet aggravated inflammatory response in ovalbumin-induced allergic mice, whereas dietary fiber intake significantly suppressed the allergic responses, attenuated allergic symptoms of nasal rubbing and sneezing, decreased the pathology of eosinophil infiltration and goblet cell metaplasia in the nasal mucosa and lung, inhibited serum OVA-specific IgE levels, and lowered the levels of Th2 cytokines in NALF and BALF, but, increased Th1 (IFN-γ) cytokines. Additionally, dietary fiber intake also increased the proportion of Bacteroidetes and Actinobacteria, and decreased Firmicutes and Proteobacteria. Levels of probiotic bacteria, such as Lactobacillus and Bifidobacterium, were upgraded significantly.ConclusionLong-term deficiency of dietary fiber intake increases the susceptibility to AAD, whereas proper fiber supplementation promotes effectively the balance of Th1/Th2 immunity and then attenuates allergic inflammatory responses significantly, as well as optimizes the structure of intestinal microbiota, which suggests potential for novel preventive and therapeutic intervention.

Heme oxygenase-1 inhibits basophil maturation and activation but promotes its apoptosis in T helper type 2-mediated allergic airway inflammation.

The anti-inflammatory role of heme oxygenase-1 (HO-1) has been studied extensively in many disease models including asthma. Many cell types are anti-inflammatory targets of HO-1, such as dendritic cells and regulatory T cells. In contrast to previous reports that HO-1 had limited effects on basophils, which participate in T helper type 2 immune responses and antigen-induced allergic airway inflammation, we demonstrated in this study, for the first time, that the up-regulation of HO-1 significantly suppressed the maturation of mouse basophils, decreased the expression of CD40, CD80, MHC-II and activation marker CD200R on basophils, blocked DQ-ovalbumin uptake and promoted basophil apoptosis both invitro and invivo, leading to the inhibition of T helper type 2 polarization. These effects of HO-1 were mimicked by exogenous carbon monoxide, which is one of the catalytic products of HO-1. Furthermore, adoptive transfer of HO-1-modified basophils reduced ovalbumin-induced allergic airway inflammation. The above effects of HO-1 can be reversed by the HO-1 inhibitor Sn-protoporphyrin IX. Moreover, conditional depletion of basophils accompanying hemin treatment further attenuated airway inflammation compared with the hemin group, indicating that the protective role of HO-1 may involve multiple immune cells. Collectively, our findings demonstrated that HO-1 exerted its anti-inflammatory function through suppression of basophil maturation and activation, but promotion of basophil apoptosis, providing a possible novel therapeutic target in allergic asthma.

Is a high-fiber diet able to influence ovalbumin-induced allergic airway inflammation in a mouse model?

Background:More recently, a large amount of experimental and clinical discovered that dietary- fiber intake would decrease the susceptibility to allergic airway disease (AAD) and respiratory inflammation.Objective:To investigate whether a fiber-intake supplement is able to influence the induction of AAD and to elucidate the interactive relationship.Methods:AAD model mice and control mice were raised on a fundamental diet with standard 4% fiber content, whereas other mice were fed a 10% fiber-content diet in the high fiber-content group, along with a 25% fiber-content diet instead in very-high fiber-content group. All experimental mice were sensitized and challenged with ovalbumin to induce allergic inflammation in both the upper and lower airways. Hallmarks of AAD were examined in terms of eosinophil infiltration and goblet cell metaplasia in subepithelial mucosa, T-helper type 1 (Th1) to Th2 skewing of the immune response. Furthermore, to elucidate the interrelations, we generated 16S ribosomal DNA from fecal samples and further validated the variation of colony composition in each group.Results:The excessive high-fiber supplement induced a promoting effect rather than a suppressive effect, including a rise in nasal rubbing and sneezing, an increase in eosinophil inflammation and goblet cell metaplasia in subepithelial mucosa, and promoted Th2 skewing of the immune response as well as the production of serum levels of ovalbumin-specific immunoglobulin E. Moreover, overconsumption of dietary fiber greatly altered the construction of bacterial flora in the intestinal tract, including an increased proportion of Firmicutes, Actinobacteria, and Proteobacteria, and a decreased proportion of Bacteroidetes.Conclusion:Our work indicated that, instead of a protecting impact, excessive fiber intake preformed a negative influence on the induction of AAD. Therefore, we suspected that an excessive supplement of dietary fiber might not be an advisable method for the prevention and treatment of AADs.

Morin Attenuates Ovalbumin-Induced Airway Inflammation by Modulating Oxidative Stress-Responsive MAPK Signaling.

Asthma is one of the most common inflammatory diseases characterized by airway hyperresponsiveness, inflammation, and remodeling. Morin, an active ingredient obtained from Moraceae plants, has been demonstrated to have promising anti-inflammatory activities in a range of disorders. However, its impacts on pulmonary diseases, particularly on asthma, have not been clarified. This study was designed to investigate whether morin alleviates airway inflammation in chronic asthma with an emphasis on oxidative stress modulation. In vivo, ovalbumin- (OVA-) sensitized mice were administered with morin or dexamethasone before challenge. Bronchoalveolar lavage fluid (BALF) and lung tissues were obtained to perform cell counts, histological analysis, and enzyme-linked immunosorbent assay. In vitro, human bronchial epithelial cells (BECs) were challenged by tumor necrosis factor alpha (TNF-α). The supernatant was collected for the detection of the proinflammatory proteins, and the cells were collected for reactive oxygen species (ROS)/mitogen-activated protein kinase (MAPK) evaluations. Severe inflammatory responses and remodeling were observed in the airways of the OVA-sensitized mice. Treatment with morin dramatically attenuated the extensive trafficking of inflammatory cells into the BALF and inhibited their infiltration around the respiratory tracts and vessels. Morin administration also significantly suppressed goblet cell hyperplasia and collagen deposition/fibrosis and dose-dependently inhibited the OVA-induced increases in IgE, TNF-α, interleukin- (IL-) 4, IL-13, matrix metalloproteinase-9, and malondialdehyde. In human BECs challenged by TNF-α, the levels of proteins such as eotaxin-1, monocyte chemoattractant protein-1, IL-8 and intercellular adhesion molecule-1, were consistently significantly decreased by morin. Western blotting and the 2′,7′-dichlorofluorescein assay revealed that the increases in intracellular ROS and MAPK phosphorylation were abolished by morin, implying that ROS/MAPK signaling contributes to the relief of airway inflammation. Our findings indicate for the first time that morin alleviates airway inflammation in chronic asthma, which probably occurs via the oxidative stress-responsive MAPK pathway, highlighting a novel profile of morin as a potent agent for asthma management.

Nickel oxide nanoparticles can recruit eosinophils in the lungs of rats by the direct release of intracellular eotaxin.

BackgroundInstillation of highly soluble nanoparticles (NPs) into the lungs of rodents can cause acute eosinophilia without any previous sensitizations by the role of dissolved ions. However, whether gradually dissolving NPs can cause the same type of eosinophilia remains to be elucidated. We selected nickel oxide (NiO) as a gradually dissolving NP and evaluated the time course pulmonary inflammation pattern as well as its mechanisms.MethodsNiO NPs were intratracheally instilled into female Wistar rats at various concentrations (50, 100, and 200 cm2/rat) and the lung inflammation was evaluated at various time-points (1, 2, 3, and 4 days). As positive controls, NiCl2 and the ovalbumin-induced allergic airway inflammation model was applied. NiCl2 was instilled at 171.1 μg Ni/rat, which is equivalent nickel concentration of 200 cm2/rat of NiO NPs. Cytological analysis and biochemical analysis including lactate dehydrogenase (LDH), total protein, and pro-inflammatory cytokines were measured in bronchoalveolar lavage fluid (BALF). The levels of total immunoglobulin E (IgE) and anaphylatoxins (C3a and C5a) were measured in BALF and serum. The levels of eotaxin were measured in the alveolar macrophages and normal lung tissue before and after addition of cell lysis buffer to evaluate whether the direct lysis of cells can release intracellular eotaxin.ResultsNiO NPs produced acute neutrophilic inflammation throughout the study. However, eosinophils were recruited at 3 and 4 days post-instillation of NiO NPs and the magnitude and pattern of inflammation was similar with NiCl2 at 24 h post-instillation. The eosinophil recruitment by NiO NPs was not related with either the levels of total IgE or anaphylatoxins. The lysis of alveolar macrophages and normal lung tissue showed high levels of intracellular eotaxin and the levels of LDH showed positive correlation with the levels of eotaxin.ConclusionsInstillation of NiO NPs produced neutrophilia at 1 and 2 days after instillation, while the mixed type of neutrophilic and eosinophilic inflammation was produced at 3 and 4 days post-instillation, which was consistent with NiCl2. The mechanism of the eosinophilia involves the direct release of intracellular eotaxin due to the rupture of cells by the accumulated solubilized nickel ions in the phagolysosome.Electronic supplementary materialThe online version of this article (doi:10.1186/s12989-016-0142-8) contains supplementary material, which is available to authorized users.

Soshiho-tang water extract inhibits ovalbumin-induced airway inflammation via the regulation of heme oxygenase-1.

BackgroundSoshiho-tang, known as Xio-hai-Hu-Tang in Chinese and Sho-Saiko-to in Japanese, has been widely used as a therapeutic agent. Its pharmacological effects include anti-inflammatory, antioxidant, antihepatic fibrosis, antitumor and immunomodulating activities. However, little is known regarding its effects on allergic asthma. Therefore, the aim of the present study was to investigate whether the Soshiho-tang water extract (SSTW) has antiasthmatic effects on airway inflammation in an ovalbumin (OVA)-induced mouse model.MethodsBALB/c mice were used as a model of asthma after induction by sensitization and challenge with OVA. We measured change in eosinophils, other inflammatory cells, and T helper 2 (Th2)-type cytokines, such as interleukin (IL)-4, IL-5, IL-13, IL-17, IL-33, and chemokine (eotaxin) in bronchoalveolar lavage fluid (BALF), presence of total and OVA-specific immunoglobulin (Ig)E in plasma, and expression of mucus production and heme oxygenase (HO)-1 protein in lung tissue.ResultsOur results show that SSTW had a suppressive effect on eosinophil influx into BALF and decreased the levels of Th2-type cytokines. Moreover, SSTW exhibited a marked decrease in mucus hypersecretion, total and OVA-specific IgE levels, and significantly induced HO-1 protein expression.ConclusionsThese results suggest that SSTW may be used as a valuable therapeutic agent for treating various inflammatory diseases including allergic asthma.

RhoA orchestrates glycolysis for TH2 cell differentiation and allergic airway inflammation

Mitochondrial metabolism is known to be important for T-cell activation. However, its involvement in effector T-cell differentiation has just begun to gain attention. Importantly, how metabolic pathways are integrated with T-cell activation and effector cell differentiation and function remains largely unknown. We sought to test our hypothesis that RhoA GTPase orchestrates glycolysis for TH2 cell differentiation and TH2-mediated allergic airway inflammation. Conditional RhoA-deficient mice were generated by crossing RhoA(flox/flox) mice with CD2-Cre transgenic mice. Effects of RhoA on TH2 differentiation were evaluated based on invitro TH2-polarized culture conditions and invivo in ovalbumin-induced allergic airway inflammation. Cytokine levels were measured by using intracellular staining and ELISA. T-cell metabolism was measured by using the Seahorse XF24 Analyzer and flow cytometry. Disruption of RhoA inhibited T-cell activation and TH2 differentiation invitro and prevented the development of allergic airway inflammation invivo, with no effect on TH1 cells. RhoA deficiency in activated T cells led to multiple defects in metabolic pathways, such as glycolysis and oxidative phosphorylation. Importantly, RhoA couples glycolysis to TH2 cell differentiation and allergic airway inflammation through regulating IL-4 receptor mRNA expression and TH2-specific signaling events. Finally, inhibition of Rho-associated protein kinase, an immediate downstream effector of RhoA, blocked TH2 differentiation and allergic airway inflammation. RhoA is a key component of the signaling cascades leading to TH2 differentiation and allergic airway inflammation at least in part through control of T-cell metabolism and the Rho-associated protein kinase pathway.

Hyperoxia promotes polarization of the immune response in ovalbumin-induced airway inflammation, leading to a TH17 cell phenotype.

Previous studies have demonstrated that hyperoxia-induced stress and oxidative damage to the lungs of mice lead to an increase in IL-6, TNF-α, and TGF-β expression. Together, IL-6 and TGF-β have been known to direct T cell differentiation toward the TH17 phenotype. In the current study, we tested the hypothesis that hyperoxia promotes the polarization of T cells to the TH17 cell phenotype in response to ovalbumin-induced acute airway inflammation. Airway inflammation was induced in female BALB/c mice by intraperitoneal sensitization and intranasal introduction of ovalbumin, followed by challenge methacholine. After the methacholine challenge, animals were exposed to hyperoxic conditions in an inhalation chamber for 24 h. The controls were subjected to normoxia or aluminum hydroxide dissolved in phosphate buffered saline. After 24 h of hyperoxia, the number of macrophages and lymphocytes decreased in animals with ovalbumin-induced airway inflammation, whereas the number of neutrophils increased after ovalbumin-induced airway inflammation. The results showed that expression of Nrf2, iNOS, T-bet and IL-17 increased after 24 of hyperoxia in both alveolar macrophages and in lung epithelial cells, compared with both animals that remained in room air, and animals with ovalbumin-induced airway inflammation. Hyperoxia alone without the induction of airway inflammation lead to increased levels of TNF-α and CCL5, whereas hyperoxia after inflammation lead to decreased CCL2 levels. Histological evidence of extravasation of inflammatory cells into the perivascular and peribronchial regions of the lungs was observed after pulmonary inflammation and hyperoxia. Hyperoxia promotes polarization of the immune response toward the TH17 phenotype, resulting in tissue damage associated with oxidative stress, and the migration of neutrophils to the lung and airways. Elucidating the effect of hyperoxia on ovalbumin-induced acute airway inflammation is relevant to preventing or treating asthmatic patients that require oxygen supplementation to reverse the hypoxemia.

Chenodeoxycholic acid attenuates ovalbumin-induced airway inflammation in murine model of asthma by inhibiting the TH2 cytokines

Asthma is a complex highly prevalent airway disease that is a major public health problem for which current treatment options are inadequate. Recently, farnesoid X receptor (FXR) has been shown to exert anti-inflammatory actions in various disease conditions, but there have been no reported investigations of Chenodeoxycholic acid (CDCA), a natural FXR agonist, in allergic airway inflammation. To test the CDCA effectiveness in airway inflammation, ovalbumin (OVA)-induced acute murine asthma model was established. We found that lung tissue express FXR and CDCA administration reduced the severity of the murine allergic airway disease as assessed by pathological and molecular markers associated with the disease. CDCA treatment resulted in fewer infiltrations of cells into the airspace and peribronchial areas, and decreased goblet cell hyperplasia, mucus secretion and serum IgE levels which was increased in mice with OVA-induced allergic asthma. The CDCA treatment further blocked the secretion of TH2 cytokines (IL-4, IL-5 and IL-13) and proinflammatory cytokine TNF-α indicate that the FXR and its agonists may have potential for treating allergic asthma.

Rapamycin inhibition of eosinophil differentiation attenuates allergic airway inflammation in mice

The mammalian target of rapamycin (mTOR) signalling pathway regulates immune responses, and promotes cell growth and differentiation. Inhibition of mTOR with rapamycin modulates allergic asthma, while the underlying molecular mechanisms remain elusive. Here, we demonstrate that rapamycin, effectively inhibits eosinophil differentiation, contributing to its overall protective role in allergic airway inflammation. Rapamycin was administered in a mouse model of ovalbumin-induced allergic airway inflammation, and the eosinophil differentiation was analysed in vivo and in vitro. Rapamycin significantly attenuated allergic airway inflammation and markedly decreased the amount of eosinophils in local airways, peripheral blood and bone marrow, independently of levels of interleukin-5 (IL-5). In vitro colony forming unit assay and liquid culture demonstrated that rapamycin directly inhibited IL-5-induced eosinophil differentiation. In addition, rapamycin reduced the production of IL-6 and IL-13 by eosinophils. Rapamycin was also capable of reducing the eosinophil levels in IL-5 transgenic NJ.1638 mice, again regardless of the constitutive high levels of IL-5. Interestingly, rapamycin inhibition of eosinophil differentiation in turn resulted in an accumulation of eosinophil lineage-committed progenitors in bone marrow. Altogether these results clearly demonstrate a direct inhibitory role of rapamycin in eosinophil differentiation and function, and reemphasize the importance of rapamycin and possibly, mTOR, in allergic airway disease.

Saponins, Especially Platyconic Acid A, from Platycodon grandiflorum Reduce Airway Inflammation in Ovalbumin-Induced Mice and PMA-Exposed A549 Cells

We investigated the inhibitory effects of Platycodon grandiflorum root-derived saponins (Changkil saponins: CKS) on ovalbumin-induced airway inflammation in mice. CKS suppressed leukocytes number, IgE, Th1/Th2 cytokines, and MCP-1 chemokine secretion in bronchoalveolar lavage fluid. Also, ovalbumin-increased MUC5AC, MMP-2/9, and TIMP-1/-2 mRNA expression, NF-κB activation, leukocytes recruitment, and mucus secretion were inhibited by CKS treatment. Moreover, the active component of CKS, platyconic acid A (PA), suppressed PMA-induced MUC5AC mRNA expression (from 2.1 ± 0.2 to 1.1 ± 0.1) by inhibiting NF-κB activation (from 2.3 ± 0.2 to 1.2 ± 0.1) via Akt (from 3.7 ± 0.3 to 2.1 ± 0.2) (p < 0.01) in A549 cells. Therefore, we demonstrate that CKS or PA suppressed the development of respiratory inflammation, hyperresponsiveness, and remodeling by reducing allergic responses, and they may be potential herbal drugs for allergen-induced respiratory disease prevention.