Chronic Asthmatic Mice Research Articles

The effect of serine protease inhibitors on airway inflammation in a chronic allergen-induced asthma mouse model.

Serine protease inhibitors reportedly attenuated airway inflammation and had antioxidant in multiorgan. However, the effects of the serine protease inhibitors nafamostat mesilate (FUT), gabexate mesilate (FOY), and ulinastatin (UTI) on a long-term challenged mouse model of chronic asthma are unclear. BALB/c mice (6 mice/group) were intratracheally inoculated with five doses of Dermatophagoides pteronyssinus (Der p; 50 μL, 1 mg/mL) at one-week intervals. Therapeutic doses of FUT (0.0625 mg/kg), FOY (20 mg/kg), or UTI (10,000 U/kg) were, respectively, injected intraperitoneally into these mice. Control mice received sterile PBS. At 3 days after the last challenge, mice were sacrificed to assess airway hyperresponsiveness (AHR), remodeling, and inflammation; lung histological features; and cytokine expression profiles. Compared with untreated controls, mice treated with FUT, FOY, and UTI had decreased AHR and goblet cell hyperplasia, decreased eosinophil and neutrophil infiltration, decreased Der p-induced IL-4 levels in serum and IL-5, IL-6, IL-13, and IL-17 levels in bronchoalveolar lavage fluid, and inhibited nuclear factor (NF)-κB activity in lung tissues. The serine protease inhibitors FUT, FOY, and UTI have potential therapeutic benefits for treating asthma by downregulating Th2 cytokines and Th17 cell function and inhibiting NF-κB activation in lung tissue.

Preventive effect of galectin-9 on double-stranded RNA-induced airway hyperresponsiveness in an exacerbation model of mite antigen-induced asthma in mice

ABSTRACTBackground. Viral respiratory infection is the most common cause of acute asthma exacerbation in patients with stable asthma. The replication of most respiratory viruses requires the generation of double-stranded RNA (dsRNA), resulting in the activation of host immune responses. Synthetic dsRNA, polyinosinic–polycytidylic acid (PolyIC), mimics the effects of viruses in various cell types. To evaluate new therapies for mite antigen-induced chronic asthma, we developed an acute exacerbation model of mouse chronic asthma using mite antigen and PolyIC. We also examined the preventive effects of recombinant galectin-9 (Gal-9) on acute asthma exacerbation in this model. Methods. Airway hyperresponsiveness (AHR) was examined to evaluate the exacerbation of chronic asthma. To analyze airway inflammation, the numbers of inflammatory cells and concentrations of cytokines in the bronchoalveolar lavage fluid (BALF) were estimated by flow cytometry and enzyme-linked immunosorbent assay, respectively. Results. AHR was accelerated by intranasal administration of PolyIC in addition to mite antigen. Levels of cytokines that contribute to AHR, including interferon-γ, tumor necrosis factor-α, and RANTES (CCR5), and of Gal-9 in the BALF were elevated in this acute asthma exacerbation mouse model. Intranasal administration of recombinant Gal-9 reduced the PolyIC-induced AHR and levels of these cytokines in the BALF. Further, Gal-9 suppressed the production of cytokines induced by PolyIC in the alveolar macrophages. Conclusions. Our findings demonstrated that exogenous Gal-9 suppressed dsRNA-induced AHR in an acute exacerbation model of chronic asthma in mice, and suggest that recombinant Gal-9 could be therapeutically effective for preventing acute asthma exacerbation.

In-depth assessment of acute and chronic house dust mite-induced asthma mouse models

Human asthmatic disease is described as a chronic inflammatory disease of the airways. However, the underlying immunological processes involved in asthmatic disease are not fully understood. Animal models have been used to uncover patho-physiologic mechanisms which relate to human disease, leading to discovery and evaluation of therapeutic targets. We have temporally characterized two models of asthma in mice, an acute and a chronic House Dust Mite (HDM) model to elucidate comparative pathways in each model and ultimately link these to human disease. Specific mechanisms of asthma were evaluated including: mucus overproduction, Th2 cytokine response, airway remodeling, airway constriction, and IgE production. The acute HDM model in female Balb/c mice is a 10 day consecutive intranasal challenge with house dust mite extract. The model has an early phase cytokine response shown through significant increases of G-CSF, TNFa, IP-10 and KC in the lung on day 1 which could be linked to mechanisms driving inflammation such as chemotaxis of neutrophils and macrophages/monocytes. The height of the inflammatory phase in the acute model is at day 7 with resolution seen by day 16. In contrast, the chronic HDM model is a 5 week model in female Balb/c mice, challenging intranasally 5 times per week with house dust mite extract. The chronic HDM model reveals significant mucus overproduction and airway remodeling characteristics such as significant upregulation of soluble collagen in the lung and tissue inhibitors of metalloproteinase -1 (TIMP-1) which has been shown to be increased in sputum and lung biopsies from asthmatic patients. By modeling the essential mechanisms involved in asthma through either the acute or chronic HDM model; we will more fully understand human disease and discover superior therapeutics to combat asthma.

Effect of mesenchymal stem cells on inhibiting airway remodeling and airway inflammation in chronic asthma

Previous studies proved that bone marrow-derived mesenchymal stem cells (BMSCs) could improve a variety of immune-mediated disease by its immunomodulatory properties. In this study, we investigated the effect on airway remodeling and airway inflammation by administrating BMSCs in chronic asthmatic mice. Forty-eight female BALB/c mice were randomly distributed into PBS group, BMSCs treatment group, BMSCs control group, and asthmatic group. The levels of cytokine and immunoglobulin in serum and bronchoalveolar lavage fluid were detected by enzyme-linked immunosorbent assay. The number of CD4(+) CD25(+) regulatory T cells and morphometric analysis was determined by flow cytometry, hematoxylin-eosin, immunofluorescence staining, periodic-acid Schiff, and masson staining, respectively. We found that airway remodeling and airway inflammation were evident in asthmatic mice. Moreover, low level of IL-12 and high levels of IL-13, IL-4, OVA-specific IgG1, IgE, and IgG2a and the fewer number of CD4(+) CD25(+) regulatory T cells were present in asthmatic group. However, transplantation of BMSCs significantly decreased airway inflammation and airway remodeling and level of IL-4, OVA-specific IgE, and OVA-specific IgG1, but elevated level of IL-12 and the number of CD4 + CD25 + regulatory T cells in asthma (P < 0.05). However, BMSCs did not contribute to lung regeneration and had no significant effect on levels of IL-10, IFN-Y, and IL-13. In our study, BMSCs engraftment prohibited airway inflammation and airway remodeling in chronic asthmatic group. The beneficial effect of BMSCs might involved the modulation imbalance cytokine toward a new balance Th1-Th2 profiles and up-regulation of protective CD4 + CD25 + regulatory T cells in asthma, but not contribution to lung regeneration.

Aldose Reductase Inhibition Prevents Allergic Airway Remodeling through PI3K/AKT/GSK3β Pathway in Mice

BackgroundLong-term and unresolved airway inflammation and airway remodeling, characteristic features of chronic asthma, if not treated could lead to permanent structural changes in the airways. Aldose reductase (AR), an aldo-sugar and lipid aldehyde metabolizing enzyme, mediates allergen-induced airway inflammation in mice, but its role in the airway remodeling is not known. In the present study, we have examined the role of AR on airway remodeling using ovalbumin (OVA)-induced chronic asthma mouse model and cultured human primary airway epithelial cells (SAECs) and mouse lung fibroblasts (mLFs).MethodsAirway remodeling in chronic asthma model was established in mice sensitized and challenged twice a week with OVA for 6 weeks. AR inhibitor, fidarestat, was administered orally in drinking water after first challenge. Inflammatory cells infiltration in the lungs and goblet cell metaplasia, airway thickening, collagen deposition and airway hyper-responsiveness (AHR) in response to increasing doses of methacholine were assessed. The TGFβ1-induced epithelial-mesenchymal transition (EMT) in SAECs and changes in mLFs were examined to investigate AR-mediated molecular mechanism(s) of airway remodeling.ResultsIn the OVA-exposed mice for 6 wks inflammatory cells infiltration, levels of inflammatory cytokines and chemokines, goblet cell metaplasia, collagen deposition and AHR were significantly decreased by treatment with AR inhibitor, fidarestat. Further, inhibition of AR prevented TGFβ1-induced altered expression of E-cadherin, Vimentin, Occludin, and MMP-2 in SAECs, and alpha-smooth muscle actin and fibronectin in mLFs. Further, in SAECs, AR inhibition prevented TGFβ1- induced activation of PI3K/AKT/GSK3β pathway but not the phosphorylation of Smad2/3.ConclusionOur results demonstrate that allergen-induced airway remodeling is mediated by AR and its inhibition blocks the progression of remodeling via inhibiting TGFβ1-induced Smad-independent and PI3K/AKT/GSK3β-dependent pathway.

Lung Resident Cells Are Independently Capable of Maintaining Chronic Asthma in Mice After Immune Ablation

Lung Resident Cells Are Independently Capable of Maintaining Chronic Asthma in Mice After Immune Ablation

Experimental research HSP70/CD80 DNA vaccine inhibits airway remodeling by regulating the transcription factors T-bet and GATA-3 in a murine model of chronic asthma

IntroductionAirway remodeling is an important pathologic feature of chronic asthma. T-bet and GATA-3, the key transcription factors for differentiation toward Th1 and Th2 cells, play an important role in the pathogenesis of airway inflammation, airway hyperresponsiveness and airway remodeling. Previous studies showed that HSP70/CD80 DNA vaccine can reduce airway hyperresponsiveness and airway inflammation in acute asthmatic mice. The present study was designed to determine the effect of HSP70/CD80 DNA vaccine on airway remodeling through regulating the development of Th1/Th2.Material and methodsBefore being sensitized and challenged by ovalbumin, the BALB/c mice were immunized with DNA vaccine. Lung tissues were assessed by histological examinations. Interferon-γ (IFN-γ)/interleukin-4 (IL-4) levels in bronchoalveolar lavage fluid were determined by ELISA and expressions of IFN-γ, IL-4, T-bet and GATA-3 in spleen were evaluated by real-time polymerase chain reaction.ResultsChronic asthmatic mice had higher airway hyperresponsiveness, a thicker airway wall, more PAS-positive goblet cells, more subepithelial extracellular matrix deposition and more proliferating airway smooth muscle (ASM)-like cells than control mice (p < 0.05). Compared with the chronic asthmatic mice, the treatment with HSP70/CD80 DNA vaccine could reduce airway hyperreactivity, mucus secretion, subepithelial collagen deposition, and smooth muscle cell proliferation (p < 0.05). DNA vaccination also increased levels of IFN-γ/IL-4 in BAL fluid (p < 0.05), and expression of T-bet/GATA-3 in the spleen (p < 0.05).ConclusionsHSP70/CD80 DNA vaccine can inhibit airway remodeling through regulating the development of Th1/Th2 subsets in asthmatic mice.

Grape Seed Proanthocyanidin Extract Attenuates Allergic Inflammation in Murine Models of Asthma

Antioxidants have been suggested to alleviate the pathophysiological features of asthma, and grape seed proanthocyanidin extract (GSPE) has been reported to have powerful antioxidant activity. This study was performed to determine whether GSPE has a therapeutic effect on allergic airway inflammation in both acute and chronic murine model of asthma. Acute asthma model was generated by intraperitoneal sensitization of ovalbumin (OVA) with alum followed by aerosolized OVA challenges, whereas chronic asthma model was induced by repeated intranasal challenges of OVA with fungal protease twice a week for 8weeks. GSPE was administered by either intraperitoneal injection or oral gavage before OVA challenges. Airway hyperresponsiveness (AHR) was measured, and airway inflammation was evaluated by bronchoalveolar lavage (BAL) fluid analysis and histopathological examination of lung tissue. Lung tissue levels of various cytokines, chemokines, and growth factors were analyzed by quantitative polymerase chain reaction and ELISA. Glutathione assay was done to measure oxidative burden in lung tissue. Compared to untreated asthmatic mice, mice treated with GSPE showed significantly reduced AHR, decreased inflammatory cells in the BAL fluid, reduced lung inflammation, and decreased IL-4, IL-5, IL-13, and eotaxin-1 expression in both acute and chronic asthma models. Moreover, airway subepithelial fibrosis was reduced in the lung tissue of GSPE-treated chronic asthmatic mice compared to untreated asthmatic mice. Reduced to oxidized glutathione (GSH/GSSG) ratio was increased after GSPE treatment in acute asthmatic lung tissue. GSPE effectively suppressed inflammation in both acute and chronic mouse models of asthma, suggesting a potential role of GSPE as a therapeutic agent for asthma.

Xiao-Qing-Long-Tang attenuates allergic airway inflammation and remodeling in repetitive Dermatogoides pteronyssinus challenged chronic asthmatic mice model

Ethnopharmacological relevanceXiao-Qing-Long-Tang (XQLT) has been used for centuries in Asia to effectively treat patients with bronchial asthma. Aim of the studyWe previously found that single and multiple doses of XQLT administered to sensitized mice before allergen challenge resulted in suppressed airway hyper-responsiveness and airway inflammation. In this study we aimed to investigate whether XQLT has the potential to attenuate the severity of asthma symptoms, and immunomodulatory mechanism of XQLT in a repetitive Dermatogoides pteronyssinus (D. pteronyssinus)-challenged chronic asthmatic mice model. Materials and methodsBALB/c mice were intratracheally (i.t.) inoculated with five doses of D. pteronyssinus (50μl, 1mg/ml) and orally administered of XQLT (1g/kg) at 1-week intervals. At three days after the last challenge, mice were sacrificed to evaluate airway remodeling, inflammation, lung histological features, and the expression profiles of cytokines and various genes. ResultsXQLT significantly reduced bronchial inflammatory cell infiltration and airway remodeling. It inhibited D. pteronyssinus-induced total IgE and D. pteronyssinus-specific IgG1 in serum, and changed the “TH2-bios” in BALF by inhibiting the activation of NF-κB. Collagen assay and Histopathology indicated that XQLT reduced airway remodeling in the lung. Simultaneously, the RT-PCR analysis showed that XQLT downregulated IL-10, IL-13, RANTES, Eotaxin, and MCP-1 mRNA expression in the lung. Moreover, EMSA and immunohistochemistry staining demonstrated that XQLT inhibited NF-κB expression in the nucleus of bronchial epithelial cells. ConclusionsThese results suggest that XQLT exhibits anti-airway inflammatory, anti-airway remodeling, and specific immunoregulatory effects in a chronic asthmatic mice model.

The Immunomodulatory Effect of You-Gui-Wan onDermatogoides-pteronyssinus-Induced Asthma

The traditional Chinese medicine You-Gui-Wan (YGW) contains ten species of medicinal plants and has been used to improve health in remissive states of asthma for hundreds of years in Asia. However, little is known about the immunomodulatory mechanisms in vivo. Therefore, this study investigated the pathologic and immunologic responses to YGW in mice that had been repeatedly exposed to Dermatogoides-pteronyssinus (Der p). YGW reduced Der-p-induced airway hyperresponsiveness and total IgE in serum. It also inhibited eosinophil infiltration by downregulating the protein expression of IL-5 in serum and changed the Th2-bios in BALF by upregulating IL-12. Results of the collagen assay and histopathologic examination showed that YGW reduced airway remodeling in the lung. In addition, after YGW treatment there was a relative decrease in mRNA expression of TGF-β1, IL-13, eotaxin, RANTES, and MCP-1 in lung in the YGW group. The results of EMSA and immunohistochemistry revealed that YGW inhibited NF-κB expression in epithelial lung cells. YGW exerts its regulative effects in chronic allergic asthmatic mice via its anti-inflammatory activity and by inhibiting the progression of airway remodeling.

Long-Term Bortezomib Treatment Reduces Allergen-Specific IgE but Fails to Ameliorate Chronic Asthma in Mice

Background: Allergen-specific immunoglobulin (Ig) E initiates the effector cascade of allergic asthma and has been identified as a valuable target for therapeutic treatment of this disease. The proteasome inhibitor bortezomib was previously shown to deplete Ig-secreting plasma cells and to efficiently suppress Ig serum titers. The present study aimed at evaluating the therapeutic potential of the proteasome inhibitor bortezomib in allergic bronchial asthma. Methods: To address this question, a chronic experimental asthma mouse model was used in a therapeutic setting. Mice were sensitized to ovalbumin (OVA) and challenged with OVA aerosol for 12 weeks. After 6 weeks of challenge, bortezomib treatment was started and continued for 1 week (short-term) or 6 weeks (long-term) with a dosage of 0.75 mg/kg body weight twice a week. Lung function, lung histology, Ig serum titers and plasma cell numbers were assessed. Results: Whereas short-term treatment lowered bronchoalveolar lavage eosinophils, long-term treatment considerably reduced serum titers of anti-OVA IgE in mice with chronic experimental asthma. However, neither short-term nor long-term treatment significantly reduced plasma cell numbers, anti-OVA IgG1 serum titers or allergic airway inflammation or ablated airway hyperresponsiveness. Conclusion: Our results suggest that bortezomib treatment has only limited value as plasma cell-depleting therapy against allergic bronchial asthma.

Long-term Bortezomib treatment reduces allergen-specific IgE but fails to ameliorate chronic asthma in mice

Background: Allergen-specific immunoglobulin (Ig) E initiates the effector cascade of allergic asthma and has been identified as a valuable target for therapeutic treatment of this disease. The proteasome inhibitor bortezomib was previously shown to deplete Ig-secreting plasma cells and to efficiently suppress Ig serum titers. The present study aimed at evaluating the therapeutic potential of the proteasome inhibitor bortezomib in allergic bronchial asthma. Methods: To address this question, a chronic experimental asthma mouse model was used in a therapeutic setting. Mice were sensitized to ovalbumin (OVA) and challenged with OVA aerosol for 12 weeks. After 6 weeks of challenge, bortezomib treatment was started and continued for 1 week (short-term) or 6 weeks (long-term) with a dosage of 0.75 mg/kg body weight twice a week. Lung function, lung histology, Ig serum titers and plasma cell numbers were assessed. Results: Whereas short-term treatment lowered bronchoalveolar lavage eosinophils, long-term treatment considerably reduced serum titers of anti-OVA IgE in mice with chronic experimental asthma. However, neither short-term nor long-term treatment significantly reduced plasma cell numbers, anti-OVA IgG1 serum titers or allergic airway inflammation or ablated airway hyperresponsiveness. Conclusion: Our results suggest that bortezomib treatment has only limited value as plasma cell-depleting therapy against allergic bronchial asthma.

Nogo-B regulates migration and contraction of airway smooth muscle cells by decreasing ARPC 2/3 and increasing MYL-9 expression

BackgroundAbnormal proliferation, apoptosis, migration and contraction of airway smooth muscle (ASM) cells in airway remodeling in asthma are basically excessive repair responses to a network of inflammatory mediators such as PDGF, but the mechanisms of such responses remain unclear. Nogo-B, a member of the reticulum family 4(RTN4), is known to play a key role in arteriogenesis and tissue repair. Further studies are needed to elucidate the role of Nogo-B in airway smooth muscle abnormalities.MethodsA mouse model of chronic asthma was established by repeated OVA inhalation and subjected to Nogo-B expression analysis using immunohistochemistry and Western Blotting. Then, primary human bronchial smooth muscle cells (HBSMCs) were cultured in vitro and a siRNA interference was performed to knockdown the expression of Nogo-B in the cells. The effects of Nogo-B inhibition on PDGF-induced HBSMCs proliferation, migration and contraction were evaluated. Finally, a proteomic analysis was conducted to unveil the underlying mechanisms responsible for the function of Nogo-B.ResultsTotal Nogo-B expression was approximately 3.08-fold lower in chronic asthmatic mice compared to naïve mice, which was obvious in the smooth muscle layer of the airways. Interference of Nogo-B expression by siRNA resulted nearly 96% reduction in mRNA in cultured HBSMCs. In addition, knockdown of Nogo-B using specific siRNA significantly decreased PDGF-induced migration of HBSMCs by 2.3-fold, and increased the cellular contraction by 16% compared to negative controls, but had limited effects on PDGF-induced proliferation. Furthermore, using proteomic analysis, we demonstrate that the expression of actin related protein 2/3 complex subunit 5 (ARPC 2/3) decreased and, myosin regulatory light chain 9 isoform a (MYL-9) increased after Nogo-B knockdown.ConclusionsThese data define a novel role for Nogo-B in airway remodeling in chronic asthma. Endogenous Nogo-B, which may exert its effects through ARPC 2/3 and MYL-9, is necessary for the migration and contraction of airway smooth muscle cells.

The Role of Bone Marrow-Derived Adult Stem Cells in a Transgenic Mouse Model of Allergic Asthma

Background: Asthmatic airway remodeling is an abnormal injury/repair process of the small airways caused by chronic inflammation in which the quantities of multiple cells increase dramatically. However, the origin of these proliferative cells is still undetermined. Objective: The aim of this study was to examine whether bone marrow (BM)-derived adult stem cells are responsible for the proliferative cells in asthmatic airway remodeling. Methods: Adult mice were durably engrafted with BM isolated from green fluorescent protein (GFP) transgenic mice. Using GFP BM chimera mice, an ovalbumin (OVA)-induced chronic asthma mouse model was established. The distribution of BM-derived GFP+ cells in the lungs of chronic asthma mice was detected by fluorescence microscopy. The phenotype of BM-derived GFP+ cells in the lung tissues of chronic asthma mice was analyzed by flow cytometry. Results: BM chimera mice were successfully generated, with no detectable radioactive inflammation observed. Using BM chimera mice, we established a mouse model of chronic asthma characterized by a significant increase in the thickness of the airway subepithelial basement membrane and smooth muscle layers. OVA treatment caused many GFP+ cells to appear at sites of small airway inflammation. The extravascular localization of some GFP+ cells and their morphology were not consistent with leukocytes. Flow cytometric analysis of lung cells revealed a significant increase in type I collagen (Col I)+GFP+ cells and α-smooth muscle actin (α-SMA)+GFP+ cells in OVA-treated GFP BM chimera mice. Conclusions: Considerable numbers of Col I- and α-SMA-producing cells originated from BM in the lung tissues of mice with OVA-induced chronic asthma.

Gene Expression Profiling in Lungs of Chronic Asthmatic Mice Treated with Galectin-3: Downregulation of Inflammatory and Regulatory Genes

Background. Asthma is a disorder characterized by a predominance of Th2 cells and eosinophilic inflammation. Suppressors of cytokine signaling (SOCS) proteins act as negative regulators of cytokine signaling. In particular, SOCS1 and SOCS3 play an important role in immune response by controlling the balance between Th1 and Th2 cells. In a previous study, we demonstrated that treatment of chronic asthmatic mice with gene therapy using plasmid encoding galectin-3 (Gal-3) led to an improvement in Th2 allergic inflammation. Methods. Using a microarray approach, this study endeavored to evaluate the changes produced by therapeutic Gal-3 delivered by gene therapy in a well-characterized mouse model of chronic airway inflammation. Results were confirmed by real-time RT-PCR, Western blot and immunohistochemical analysis. Results. We identify a set of genes involved in different pathways whose expression is coordinately decreased/increased in mice treated with Gal-3 gene therapy. We report a correlation between Gal-3 treatment and inhibition of SOCS1 and SOCS3 expression in lungs. Conclusion. These results suggest that negative regulation of SOCS1 and 3 following Gal-3 treatment could be a valuable therapeutic approach in allergic disease.

Pulmonary histone deacetylase is involved in phenotype transformation of airway smooth muscle cells in chronic asthmatic mice

Objective To investigate the changes of histone deacetylase ( HDAC) activity during chronic asthma and its effects on the phenotype and biological activities of airway smooth muscle cells. Methods Chronic asthma model was established with mice using repeated sensitization and challenge with OVA,and the lung was homogenated for total HDAC activity assay. Rat airway smooth muscle cells and human bronchial smooth muscle cells were stimulated with trichostatin A ( TSA) ,an HDAC inhibitor. The effect of HDAC inhibition on phenotype switching was detected by Western Blotting analysis,and its effects on proliferation,migration and contraction of smooth muscle cells were examined by MTT,Transwell and gel contraction,respectively. Results The total HDAC activity was significantly decreased in chronic asthmatic mice compared with saline -treated controls( [0. 371 ± 0. 054]vs[0. 603 ± 0. 034]μmol/( L·μg) ,P 0. 01). Incubation of the rat trachea ring and human bronchial smooth muscle cells with TSA ( 0. 5 μmol/ L) for 12 -24 h increased the expression of α -sm -actin and SM22 -α. TSA significantly decreased cell number after 24 h treatment ( [1. 719 ±0. 044) ×104 vs( [1. 911 ±0. 048]×104,P 0. 05) and 48 h[1. 808 ±0. 009]×104 vs[2. 537 ±0. 01]×104,P 0. 05) compared with DMSO controls. TSA treatment for 24 h also significantly decreased the migrated cells compared with the PDGF -treated cells( 52 ± 7. 5 vs 88 ± 7. 632,P 0. 05). Furthermore,the gel contraction rate was significantly lower in the TSA -treated cells than in the DMSO or PDGF-treated cells( [9. 885 ± 7. 084]% vs [44. 844 ± 3. 808]% and [41. 315 ± 7. 943]% ,P 0. 05). Conclusion HDAC activity is decreased in the lung of chronic asthmatic mice,which may be related to switching of the airway smooth muscle cells to a "contractic" phenotype,but with no increase of their contraction capability.

TRPC expressions in the lung tissue of chronic asthmatic mice

TRPC expressions in the lung tissue of chronic asthmatic mice

Increased Expression of Angiopoietins and Tie2 in the Lungs of Chronic Asthmatic Mice

Angiopoietin (Ang)1 and Ang2 are ligands for Tie2 tyrosine kinase receptor (Tie2). Elevated levels of Ang1 and Ang2 in induced sputum of patients with asthma have been reported, with a positive correlation of Ang2 levels with the severity of airway occlusion. Although studies have shown Tie2-mediated regulation of nonvascular cells in some pathological conditions, current knowledge on Tie2 signaling in asthma is limited to the vasculature. We examined the expression pattern of Ang1, Ang2, vascular endothelial growth factor (VEGF), and Tie2 and their correlation with the degree of airway remodeling in the lung of ovalbumin (OVA)-sensitized and OVA-challenged mice with airway hyperresponsiveness. Lung tissues were isolated from Balb/c mice after OVA sensitization and challenge. Hematoxylin and eosin, periodic acid-Schiff, and trichrome staining were used to show the lung pathology. The expression of Ang1, Ang2, VEGF, and Tie2 was examined using immunofluorescence, Western blot, ELISA, and real-time PCR. In the lung of normal mice, Tie2 expression was detected only in the blood vessels. However, in the lung of OVA-sensitized and OVA-challenged mice, Tie2 was abundantly expressed in airway epithelial cells and in a subset of macrophages in addition to constitutive expression in pulmonary vessels. The increase in Tie2 expression correlated with the severity of airway remodeling. Macrophages and airway epithelial cells express Ang2 and VEGF only in allergic models. Ang1 was constitutively expressed, with a decrease in mRNA level in allergic models. In conclusion, increased expression of Tie2 and Ang2 in allergic airway epithelium and alveolar macrophages correlates with the severity of airway remodeling.

Regulatory T Cells Negatively Regulate Neovasculature of Airway Remodeling via DLL4-Notch Signaling

Regulatory T cells (Treg) have been shown to prevent the development of allergic asthma; however, the role of Treg in asthma with established airway remodeling is unknown. To address this, we exploited an OVA-induced chronic asthma mouse model wherein Treg were adoptively transferred to the mice at chronic stage of the model. We found that among the structural alterations of airway remodeling, Treg selectively reduced the vessel numbers in both peritracheal and peribronchial regions and the lung parenchyma. Extracellular matrix deposition, mucus metaplasia, muscular hyperplasia, and vasodilation, as were also induced by chronic allergen challenge, were not affected by Treg. TUNEL staining of the lung sections revealed an increased endothelial cell (EC) apoptosis in mice receiving Treg transfers compared with their asthmatic counterparts. By using Matrigel angiogenesis assays, we showed that Treg inhibited EC angiogenesis both in vitro and in vivo. Treg preferentially expressed Notch ligand DLL4, and an anti-DLL4 blocking Ab abrogated the inhibitory effect of Treg on EC tube formation. In vivo, decreased airway and lung vessel numbers as well as ameliorated airway hyperresponsiveness after Treg transfers were reverted when Treg-derived DLL4 signal was blocked by the anti-DLL4 Ab. Our findings demonstrate a novel function of Treg whereby Treg down-regulate remodeling angiogenesis via proapoptotic DLL4-Notch signaling, and suggest a therapeutic potential of Treg in alleviating airway hyperresponsiveness of chronic asthma.

Combined sensitization of mice to extracts of dust mite, ragweed, and Aspergillus species breaks through tolerance and establishes chronic features of asthma

Existing asthma models develop tolerance when chronically exposed to the same allergen. We sought to establish a chronic model that sustains features of asthma long after discontinuation of allergen exposure. We immunized and exposed mice to a combination of single, double, or triple allergens (dust mite, ragweed, and Aspergillus species) intranasally for 8 weeks. Airway hyperreactivity (AHR) and morphologic features of asthma were studied 3 weeks after allergen exposure. Signaling effects of the allergens were studied on dendritic cells. Sensitization and repeated exposure to a single allergen induced tolerance. Sensitization to double and especially triple allergens broke through tolerance and established AHR, eosinophilic inflammation, mast cell and smooth muscle hyperplasia, mucus production, and airway remodeling that persisted at least 3 weeks after allergen exposure. Mucosal exposure to triple allergens in the absence of an adjuvant was sufficient to induce chronic airway inflammation. Anti-IL-5 and anti-IL-13 antibodies inhibited inflammation and AHR in the acute asthma model but not in the chronic triple-allergen model. Multiple allergens produce a synergy in p38 mitogen-activated protein kinase signaling and maturation of dendritic cells, which provides heightened T-cell costimulation at a level that cannot be achieved with a single allergen. Sensitivity to multiple allergens leads to chronic asthma in mice. Multiple allergens synergize in dendritic cell signaling and T-cell stimulation that allows escape from the single allergen-associated tolerance development.