Airway Remodeling In Mouse Model Research Articles

Effect of Calycosin on Airway Inflammation and Airway Remodeling in Allergic Asthma Mouse Model

Background: This study aimed to construct a TDI-induced mouse model of asthma, and evaluate the potential effects and possible molecular mechanisms of Calycosin on airway inflammation and airway remodeling in mouse model. Material and methods: ELISA method was applied to detect the total serum IgE level and the inflammatory cytokine level in the bronchoalveolar lavage fluid. The total number of cells and the proportion of inflammatory cells in BALF were evaluated under an optical microscope. HE was employed to assess and score the infiltration of peritracheal and perivascular inflammatory cells in lung tissue, and PAS staining was used to assess the proportion of goblet cells in the airway epithelium and the thickness of airway epithelial reticular basement membrane in each group of mice. WB was used to detect the expressions of HMGB1 and a-SMA in cells. Immunofluorescence staining was used to detect the expressions of HMGB1 and a-SMA in 16HBEs. Results: The airway hyperresponsiveness of the Calycosin TDI asthma mice decreased, the inflammatory factors in BALF and the total serum IgE levels decreased, the airway epithelial goblet cell metaplasia and the thickness of the airway epithelial reticular basement membrane were improved, thus reducing the up-regulation of HMGB1 and a-SMA expression of 16HBES induced by TDI-HSA. Conclusion: In our study, in the TDI-induced mouse model of asthma, the administration of drug to inhibit the activation of AKT can reduce airway inflammation and airway remodeling. These findings have enriched the current understanding of Calycosin and provided a basis for future research. However, there are also some limitations: How does TDI activate the AKT signaling pathway? After the activation of the AKT pathway, the mechanism by which the expressions of HMGB1, α-SMA and Collagen-I were up-regulated has not been fully elucidated.

House dust mite-induced Akt-ERK1/2-C/EBP beta pathway triggers CCL20-mediated inflammation and epithelial-mesenchymal transition for airway remodeling.

House dust mite (HDM) allergens cause inflammatory responses and chronic allergic diseases such as bronchial asthma and atopic dermatitis. Here, we investigate the mechanism by which HDM induces C-C chemokine ligand 20 (CCL20) expression to promote chronic inflammation and airway remodeling in an HDM-induced bronchial asthma mouse model. We showed that HDM increased CCL20 levels via the Akt-ERK1/2-C/EBPβ pathway. To investigate the role of CCL20 in chronic airway inflammation and remodeling, we made a mouse model of CCL20-induced bronchial asthma. Treatment of anti-CCL20Ab in this mouse model showed the reduced airway hyper-responsiveness and inflammatory cell infiltration into peribronchial region by neutralizing CCL20. In addition, CCL20 induced the Nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation through NLRP3 deubiquitination and transcriptional upregulation in BEAS-2B cells. As expected, anti-CCL20Ab markedly suppressed NLRP3 activation induced by CCL20. Moreover, HDM-induced CCL20 leads to epithelial-mesenchymal transition in the lung epithelium which appears to be an important regulator of airway remodeling in allergic asthma. We also found that anti-CCL20Ab attenuates airway inflammation and remodeling in an HDM-induced mouse model of bronchial asthma. Taken together, our results suggest that HDM-induced CCL20 is required for chronic inflammation that contributes airway remodeling in a mouse model of asthma.

Calcio-herbal formulation, Divya-Swasari-Ras, alleviates chronic inflammation and suppresses airway remodelling in mouse model of allergic asthma by modulating pro-inflammatory cytokine response

Asthma is a chronic allergic respiratory disease with limited therapeutic options. Here we validated the potential anti-inflammatory, anti-asthmatic and immunomodulatory therapeutic properties of calcio-herbal ayurvedic formulation, Divya-Swasari-Ras (DSR) in-vivo, using mouse model of ovalbumin (OVA) induced allergic asthma. HPLC analysis identified the presence of various bioactive indicating molecules and ICP-OES recognized the presence of Ca mineral in the DSR formulation. Here we show that DSR treatment significantly reduced cardinal features of allergic asthma including inflammatory cell accumulation, specifically lymphocytes and eosinophils in the Broncho-Alveolar Lavage (BAL) fluids, airway inflammation, airway remodelling, and pro-inflammatory molecules expression. Conversely, number of macrophages recoverable by BAL were increased upon DSR treatment. Histology analysis of mice lungs revealed that DSR attenuates inflammatory cell infiltration in lungs and thickening of bronchial epithelium. PAS staining confirmed the decrease in OVA-induced mucus secretion at the mucosal epithelium; and trichrome staining confirmed the decrease in peribronchial collagen deposition upon DSR treatment. DSR reduced the OVA-induced pro-inflammatory cytokines (IL-6, IL-1β and TNF-α) levels in BALF and whole lung steady state mRNA levels (IL-4, -5, -33, IFN-γ, IL-6 and IL-1β). Biochemical assays for markers of oxidative stress and antioxidant defence mechanism confirmed that DSR increases the activity of SOD, Catalase, GPx, GSH, GSH/GSSG ratio and decreases the levels of MDA activity, GSSG, EPO and Nitrite levels in whole lungs. Collectively, present study suggests that, DSR effectively protects against allergic airway inflammation and possess potential therapeutic option for allergic asthma management.

Sevoflurane Prevents Airway Remodeling via Downregulation of VEGF and TGF-β1 in Mice with OVA-Induced Chronic Airway Inflammation.

Asthma is characterized by chronic airway inflammation, which is the underlying cause of airway remodeling featured by goblet cell hyperplasia, subepithelial fibrosis, and proliferation of smooth muscle. Sevoflurane has been used to treat life-threatening asthma and our previous study shows that sevoflurane inhibits acute lung inflammation in ovalbumin (OVA)-induced allergic mice. However, the effect of sevoflurane on airway remodeling in the context of chronic airway inflammation and the underlying mechanism are still unknown. Here, female C57BL/6 mice were used to establish chronic airway inflammation model. Hematoxylin and eosin (H&E), periodic acid-Schiff (PAS), and Sirius red (SR) staining were used to evaluate airway remodeling. Protein levels of α-SMA, VEGF, and TGF-β1 in lung tissues were detected by western blotting analyses and immunohistochemistry staining. Results showed that inhalation of sevoflurane inhibited chronic airway inflammation including inflammatory cell infiltration and pro-inflammatory cytokine production in BALF of the OVA-challenged mice. Meanwhile, sevoflurane suppressed airway thickening, goblet cell hyperplasia, smooth muscle hyperplasia, collagen deposition, and fiber hyperplasia in the lung tissues of the mice with airway remodeling. Most notably, sevoflurane inhibited the OVA-induced expressions of VEGF and TGF-β1. These results suggested that sevoflurane effectively inhibits airway remodeling in mouse model of chronic airway inflammation, which may be due to the downregulation of VEGF and TGF-β1in lung tissues. Therefore, our results indicate a potential role of sevoflurane in inhibiting airway remodeling besides its known suppression effect on airway inflammation, and support the use of sevoflurane in treating severe asthma in ICU.

Effect of nintedanib on airway inflammation and remodeling in a murine chronic asthma model

ABSTRACTIntroduction: Nintedanib is a multi-tyrosine kinase receptor inhibitor recently approved for treatment of idiopathic pulmonary fibrosis. Although angiogenesis is a key process involved in airway structural changes in patients with bronchial asthma, the effect of nintedanib targeting the angiokinase pathway on airway inflammation and remodeling has not been evaluated. Methods: We used a 3-month ovalbumin (OVA) challenge mouse model of airway remodeling. Nintedanib was orally administrated during the challenge period, and the effects were examined based on the percentage of airway inflammatory cells, airway hyper-reactivity (AHR), peribronchial goblet cell hyperplasia, total lung collagen and smooth muscle area. The expression of growth factor receptors was analyzed in mice lung tissues. Results: The OVA challenged group showed a significant increase in airway eosinophilic inflammation, elevated Th2 cytokines, AHR, and airway remodeling compared to those in the control group. The airway remodeling process, as evaluated by goblet cell hyperplasia, total lung collagen level, and airway smooth muscle area, was suppressed by nintedanib compared to that by OVA. Nintedanib effectively suppressed the phosphorylation of vascular endothelial growth factor/ platelet derived growth factor subunit2/fibroblast growth factor3 receptors in the mice lung. Conclusions: Nintedanib effectively ameliorated airway inflammation and remodeling in an OVA-induced chronic asthma model. These results suggest that nintedanib could be a new treatment agent targeting airway remodeling in patients with severe asthma.

LIGHT and IL-1β contribute to airway remodeling in a mouse model of recurrent rhinovirus infection

Abstract Airway remodeling is defined by several structural changes including mucus metaplasia, increased peribronchial smooth muscle thickness and subepithelial fibrosis. Rhinoviruses (RVs) have been demonstrated to upregulate many airway inflammatory and remodeling factors that are implicated in the pathogenesis of asthma. Studies from our lab previously identified a tumor necrosis factor family member, LIGHT (TNFSF14), as an essential mediator of airway remodeling in an allergen-driven mouse model of severe asthma. In the present study, we examined effect of RV infection on induction of LIGHT and airway remodeling. We observed increased LIGHT mRNA after RV infection in an A549 cell line as well as in vivo after infection in the lung, and furthermore neutrophils were found to be another potential source of LIGHT. Recurrent infection of RV induced salient features of airway remodeling resembling those found in severe asthmatics. LIGHT−/− mice showed reduced neutrophilia and impairment in fibrosis and smooth muscle mass and lung collagen. Blocking LIGHT signaling with LTβRFc also inhibited subepithelial fibrosis and smooth muscle thickness. Recurrent infection of RV in the presence of house dust mite allergen further exacerbated the smooth muscle thickness and subepithelial fibrosis and this was again significantly reduced in LIGHT−/− mice. Recurrent infection of RV also induced IL-1β mRNA and neutralizing IL-1β signaling further reduced the subepithelial collagen deposition and smooth muscle thickness. This study extends our present knowledge of how viruses might cause worsening of allergic airway inflammation and promote airway remodeling in asthma by identifying LIGHT and IL-1β as being active during the response to rhinovirus.

Effect of intranasal rosiglitazone on airway inflammation and remodeling in a murine model of chronic asthma.

Background/Aims:Asthma is characterized by airway hyperresponsiveness, inflammation, and remodeling. Peroxisome proliferator-activated receptors have been reported to regulate inflammatory responses in many cells. In this study, we examined the effects of intranasal rosiglitazone on airway remodeling in a chronic asthma model.Methods:We developed a mouse model of airway remodeling, including smooth muscle thickening, in which ovalbumin (OVA)-sensitized mice were repeatedly exposed to intranasal OVA administration twice per week for 3 months. Mice were treated intranasally with rosiglitazone with or without an antagonist during OVA challenge. We determined airway inflammation and the degree of airway remodeling by smooth muscle actin area and collagen deposition.Results:Mice chronically exposed to OVA developed sustained eosinophilic airway inflammation, compared with control mice. Additionally, the mice developed features of airway remodeling, including thickening of the peribronchial smooth muscle layer. Administration of rosiglitazone intranasally inhibited the eosinophilic inflammation significantly, and, importantly, airway smooth muscle remodeling in mice chronically exposed to OVA. Expression of Toll-like receptor (TLR)-4 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) was increased in the OVA group and decreased in the rosiglitazone group. Co-treatment with GW9660 (a rosiglitazone antagonist) and rosiglitazone increased the expression of TLR-4 and NF-κB.Conclusions:These results suggest that intranasal administration of rosiglitazone can prevent not only air way inf lammation but also air way remodeling associated with chronic allergen challenge. This beneficial effect is mediated by inhibition of TLR-4 and NF-κB pathways.

Effect of nilotinib on airway remodeling in a murine model of chronic asthma

ABSTRACTObjective: The tyrosine kinase inhibitor nilotinib has potent inhibitory activity against the stem cell growth factor receptor c-Kit and platelet-derived growth factor receptor (PDGFR). The present study aimed to determine whether nilotinib suppresses airway remodeling and whether its effect is associated with the c-Kit and PDGFR pathways. We also aimed to compare the effect of nilotinib and imatinib on remodeling. Methods: We developed a mouse model of airway remodeling, which includes smooth muscle thickening, in which ovalbumin (OVA)-sensitized mice were repeatedly exposed to intranasal OVA administration twice a week for 3 months. Mice were treated with nilotinib or imatinib during the OVA challenge. Results: Compared with control mice, the mice chronically exposed to OVA developed sustained eosinophilic airway inflammation, airway hyperresponsiveness (AHR), and exhibited features of airway remodeling, including thickening of the peribronchial smooth muscle layer. Administration of nilotinib significantly inhibited eosinophilic inflammation, AHR, and remodeling in mice chronically exposed to OVA. Nilotinib showed a trend of more potent effect than imatinib on attenuating remodeling in hydroxyproline assay and smooth muscle staining. Nilotinib treatment significantly reduced the expression of phosphorylated (p)-c-Kit, p-PDGFRβ, and p-extracellular signal-regulated kinase 1/2. The expression levels of the genes encoding c-Kit and PDGFRβ were also reduced by nilotinib treatment. Treatment with nilotinib did not affect significantly the level of OVA-specific IgE and IgG1 in serum. In vitro, nilotinib significantly inhibited cell proliferation of fibroblast. Conclusions: These results suggest that nilotinib administration can prevent airway inflammation, AHR, and airway remodeling associated with chronic allergen challenge.

Poster 1013: IL-4R alpha antibody inhibits IgE production and airway remodeling in mouse model of house dust mite-induced eosinophilic asthma

Background Allergic asthma is associated with T helper 2 (Th2) immune response to an allergen. IL-4 and IL-13, key cytokines involved in Th2 immunity, promote eosinophilic inflammation and B cell isotype switching to IgE. House Dust Mite (HDM) allergen has been shown to induce allergic asthma in a mouse model via Th2 immune response that drives eosinophilia and influx of effector T cells into lung. An IL-4Raplha antibody that blocks signaling of IL-4 and IL-13 through both Type I (IL-4Ralpha/ IL-2Rgamma) and Type II (IL-4Ralpha/IL-13R) receptors, and an IL-13Ra2-Fc fusion protein that prevents binding and signaling of IL-13 via Type II receptor, were both tested in the HDM-induced mouse model of asthma. Methods Mice were sensitized daily for 10 days with HDM, rested for 2 weeks, followed by challenge with HDM three times weekly for 8 weeks. Both anti-mouse IL-4Ralpha; antibody (Ab) and fully human anti-human IL-4Raplha Ab (dupilumab) were tested in wild type mice and mice humanized for IL-4 and IL-4Ralpha, respectively. Mice were treated with 50 mg/kg of either Ab twice weekly, starting at week 7 of the experiment. A separate group received mouse IL-13Raplha2-Fc protein using the same dose and regimen. At the end of the experiment, cells obtained by left lung lobe tissue digest were analyzed by flow cytometry. Lung collagen indicative of an airway remodeling was quantified using a Sircol Dye assay, and cardiac lung lobe was used for microarray analysis of gene signature. Levels of HDM-specific IgG1 and total IgE in serum were analyzed by ELISA. Results HDM sensitization and challenge resulted in increased levels of IgE and HDM-specific IgG1. IgE increase was blocked by IL-4Ra Ab but not by IL-13Ralpha2-Fc treatment; HDM-specific IgG1 levels were not affected by either treatment. Collagen content in lung of mice treated with IL-4Ralpha mAb was similar to that observed in mock sensitized and challenged mice. Dupilumab treatment also prevented the influx of eosinophils and inflammatory dendritic cells into lung. HDM-induced changes in gene expression were largely normalized upon dupilumab treatment, as compared to mock treated and sensitized mice.

Allergen-Induced Coexpression of bFGF and TGF-β1 by Macrophages in a Mouse Model of Airway Remodeling: bFGF Induces Macrophage TGF-β1 Expression in vitro

Background: Basic fibroblast growth factor (bFGF) is a cytokine that is mitogenic for fibroblasts and smooth muscle and may play a role in airway remodeling in asthma. We have used a mouse model of chronic ovalbumin (OVA) allergen-induced airway remodeling to determine whether bFGF and fibroblast growth factor receptor-1 are expressed and regulated by corticosteroids in the airway, as well as to determine whether bFGF mediates expression of another proremodeling cytokine, transforming growth factor (TGF)-β1. Methods: The airway levels and localization of bFGF, FGF receptor-1 and TGF-β1 were determined by ELISA, immunohistology and image analysis in the remodeled airways of chronic OVA-challenged mice treated with either corticosteroids or diluent. In vitro cultures of bone narrow-derived macrophages were used to determine whether bFGF induced TGF-β1 expression. Results: Mice chronically challenged with OVA developed significant airway remodeling that was associated with significantly increased levels of bFGF and TGF-β1. Immunohistochemistry demonstrated significantly increased bFGF and FGF receptor-1 expression by peri- bronchial F4/80+ cells. Double-label immunofluorescence microscopy studies demonstrated that peribronchial macrophages coexpressed bFGF and TGF-β1. In vitro studies demonstrated that incubation of bone marrow-derived macrophages with bFGF induced expression of TGF-β1. Mice treated with corticosteroids and subjected to chronic OVA challenge had significantly reduced levels of bFGF, FGF receptor-1, peribronchial TGF-β1+ cells and airway remodeling. Conclusions: Overall, this study demonstrates that allergen challenge stimulates peribronchial macrophages to coexpress bFGF and TGF-β1 and that bFGF may potentiate macrophage release of TGF-β1 through autocrine and/or paracrine pathways.

Effect of Peroxisome Proliferator-Activated Receptor-Gamma on Airway Smooth Muscle Thickening in a Murine Model of Chronic Asthma

Background: Asthma is characterized by airway hyperresponsiveness (AHR), inflammation and remodeling. Peroxisome proliferator-activated receptors (PPARs) were reported to regulate inflammatory responses in many cells. In this study we examined the effect of a PPAR-γ agonist on the airway smooth muscle and the production of transforming growth factor (TGF)-β1 and vascular endothelial growth factor (VEGF). Methods: We developed a mouse model of airway remodeling including smooth muscle thickening in which ovalbumin (OVA)-sensitized mice were repeatedly exposed to intranasal OVA administration twice a week for 3 months. Mice were treated intranasally with ciglitazone during OVA challenge. Results: Mice chronically exposed to OVA developed sustained eosinophilic airway inflammation and AHR to methacholine compared with control mice. In addition, the mice chronically exposed to OVA developed features of airway remodeling, including thickening of the peribronchial smooth muscle layer. Administration of ciglitazone intranasally significantly inhibited the development of AHR, eosinophilic inflammation, and importantly, airway smooth muscle remodeling in mice chronically exposed to OVA. However, intranasal ciglitazone treatment did not reduce the level of TGF-β1 and VEGF in bronchoalveolar lavage fluid. Conclusions: These results suggest that intranasal administration of ciglitazone can prevent not only airway inflammation, but also airway remodeling associated with chronic allergen challenge. The mechanism might not be related to VEGF and TGF production. Further study is needed.

Induction of airway remodeling of nasal mucosa by repetitive allergen challenge in a murine model of allergic rhinitis

Although many studies regarding airway remodeling in asthma have been reported, only a few studies have investigated airway remodeling in allergic rhinitis. To determine whether repetitive allergen challenge could induce airway remodeling in the nose and evaluate the effect of steroids using a murine model of allergic rhinitis. To develop a mouse model of airway remodeling, ovalbumin-sensitized mice were repeatedly exposed to inhaled ovalbumin administration twice a week for 1 month and 3 months. Matched control mice were challenged with phosphate-buffered saline, and the treatment group received intraperitoneal dexamethasone injection. Trichrome, periodic acid-Schiff, hematoxylin-eosin, and immunohistochemical staining against matrix metalloproteinase 9 and tissue inhibitors of metalloproteinase 1 were performed to nasal and lung tissues, and the level of transforming growth factor beta in the nasal lavage fluid was analyzed. Repetitive ovalbumin challenge for 3 months induced circumferential peribronchial fibrosis in the lung. In the nose, subepithelial fibrosis, increased matrix metalloproteinase 9 and tissue inhibitors of metalloproteinase 1 expression, goblet cell hyperplasia, and submucous gland hypertrophy were observed compared with the control group. Features of airway remodeling were more prominent in the lung tissue. Administration of dexamethasone significantly inhibited these histologic changes. Airway remodeling associated with long-term allergen challenge can occur in the nasal mucosa and the lung. Steroid treatment prevents airway inflammation in response to acute allergen challenge, as well as airway remodeling by long-term allergen challenge.

Inhaled corticosteroid prevents the thickening of airway smooth muscle in murine model of chronic asthma

Airway smooth muscle growth contributes to the mechanism of airway hyperresponsiveness (AHR) in asthma. Although current steroid use demonstrates anti-inflammatory activity, there is little reported on the action of corticosteroid on smooth muscle of the asthmatic airway. The present study investigated the effect of inhaled corticosteroid on the thickening of airway smooth muscle in bronchial asthma. We developed a mouse model of airway remodeling including smooth muscle thickening in which ovalbumin (OVA)-sensitized female BALB/c-mice were repeatedly exposed to intranasal OVA administration twice a week for 3 months. Mice were treated intranasally with fluticasone during the OVA challenge. Mice chronically exposed to OVA developed sustained eosinophilic airway inflammation compared with control mice. In addition, the mice chronically exposed to OVA developed features of airway remodeling, including thickening of the peribronchial smooth muscle layer. Intranasal administration of fluticasone inhibited the development of eosinophilic inflammation, and importantly, thickening of the smooth muscle layer. Moreover, intranasal fluticasone treatment reduced the transforming growth factor (TGF)- β1 level in bronchoalveolar lavage fluid and regulated active TGF- β1 signaling with a reduction in the expression of phospho-Smad2/3 and the concomitant up-regulation of Smad7 in lung tissue sections. These results suggest that intranasal administration of fluticasone can modulate the remodeling of airway smooth muscle via regulation of TGF- β1 production and active TGF- β1 signaling.

Remodeling associated expression of matrix metalloproteinase 9 but not tissue inhibitor of metalloproteinase 1 in airway epithelium: Modulation by immunostimulatory DNA

Matrix metalloproteinase 9 (MMP-9) and its tissue inhibitor of metalloproteinase 1 (TIMP-1) are hypothesized to play a role in the pathogenesis of airway remodeling in asthma. We have used a mouse model of airway remodeling to determine the pattern of expression of MMP-9 and TIMP-1 in airway epithelium and peribronchial cells, and assess whether TIMP-1, an inhibitor of MMP-9, is expressed at the same sites in the airway. In addition, we have investigated whether immunostimulatory sequences (ISSs) of DNA modulate levels of expression of MMP-9, TIMP-1, and peribronchial fibrosis. Levels of lung MMP-9 and TIMP-1 were assessed by zymography, ELISA, and immunohistochemistry. Repetitive ovalbumin challenge induced a significant increase in levels of MMP-9, TIMP-1, and peribronchial collagen deposition. The pattern of expression of MMP-9 and TIMP-1 in the remodeled airway was significantly different. MMP-9 but not TIMP-1 was expressed in airway epithelium, whereas both MMP-9 and TIMP-1 were expressed in peribronchial inflammatory cells. ISS significantly reduced expression of MMP-9 in airway epithelium (which immunostained positive for Toll receptor 9), as well as in peribronchial inflammatory cells. In vitro studies demonstrated that ISS inhibited bone marrow macrophage generation of MMP-9. Allergen-induced peribronchial fibrosis is associated with expression of MMP-9 and TIMP-1 at different anatomical sites in the remodeled airway. The ability of ISS to inhibit the expression of MMP-9 in airway epithelium (a site where its inhibitor TIMP-1 is not induced by allergen challenge) may be important in determining whether ISS contributes to reductions in airway remodeling by reducing levels of MMP-9. Immunostimulatory sequences of DNA, which are being investigated as novel therapeutics in asthma, inhibit airway remodeling in mice as well as epithelial expression of MMP-9, an enzyme that degrades the extracellular matrix proteins surrounding the airway.

ISS inhibits expression of MMP-9 and MMP-2 in a mouse model of airway remodeling

Rationale MMPs are involved in the regulation of collagen deposition in the extracellular matrix. We investigated whether repetitive allergen challenge in mice induces expression of MMPs and TIMP-1 in the remodeled airway and whether ISS modulates expression of MMPs and TIMP-1. Methods Mice were repetitively challenged with OVA for 3 months to assess levels of MMP and TIMP expression (Elisa, immunohistochemistry). Levels of total lung collagen were measured by the Sircol soluble collagen assay. The effect of ISS on MMP and TIMP-1 expression was assessed by pretreating ova challenged mice with ISS every 2 weeks. Results Repetitive ova challenge induced a significant increase in the levels of lung MMP-9, MMP-2, and TIMP-1 (p=0.01). ISS treatment of ova challenged mice significantly reduced the levels of MMP-9,-2 and TIMP-1 compared to ova challenged mice not treated with ISS (p=0.01). Repetitive ova challenge induced a significant increase in the levels of lung collagen(p=0.01). ISS treatment of ova challenged mice significantly reduced the levels of lung collagen compared to ova challenged mice not treated with ISS (p=0.01, n=16). Conclusion Repetitive ova challenge induces increased levels of lung collagen which is associated with increased levels of expression of MMP-9, -2, and TIMP-1. ISS reduces lung collagen levels, as well as levels of MMP-9, -2 and TIMP-1, suggesting a role for ISS in inhibiting airway remodeling.

Immunostimulatory DNA inhibits transforming growth factor-beta expression and airway remodeling.

Immunostimulatory sequences of DNA (ISS) inhibit eosinophilic airway inflammation, Th2 responses, and airway hyperreactivity (AHR) in mouse models of acute ovalbumin (OVA)-induced airway inflammation. To determine whether ISS inhibits airway remodeling, we developed a mouse model of airway remodeling in which OVA-sensitized mice were repeatedly exposed to intranasal OVA administration for 1-6 mo. Mice chronically exposed to OVA developed sustained eosinophilic airway inflammation and sustained AHR to methacholine compared with control mice. In addition, the mice chronically exposed to OVA developed features of airway remodeling, including thickening of the peribronchial smooth muscle layer, peribronchial myofibroblast accumulation, expression of the profibrotic growth factor transforming growth factor-beta, and subepithelial collagen deposition (assessed by quantitation of the area of peribronchial trichrome staining using image analysis, and immunostaining with anti-collagen V antibodies). Administration of ISS systemically every other week significantly inhibited the development of AHR, eosinophilic inflammation, airway mucus production, and importantly, airway remodeling in mice chronically exposed to OVA for 3-6 mo. In addition, ISS significantly reduced bronchoalveolar lavage and lung levels of the profibrotic cytokine transforming growth factor-beta. These studies demonstrate that ISS prevents not only Th2-mediated airway inflammation in response to acute allergen challenge, but also airway remodeling associated with chronic allergen challenge.