Activation of the Complement and Coagulation Systems in the Small Airways in Asthma.

BACKGROUND: Several studies have shown the importance of the complement and coagulation systems in the pathogenesis of asthma. OBJECTIVES: We explored whether we could detect differentially abundant complement and coagulation proteins in the samples obtained from the small airway lining fluid by collection of exhaled particles in patients with asthma and whether these proteins are associated with small airway dysfunction and asthma control. METHOD: Exhaled particles were obtained from 20 subjects with asthma and 10 healthy controls (HC) with the PExA method and analysed with the SOMAscan proteomics platform. Lung function was assessed by nitrogen multiple breath washout test and spirometry. RESULTS: 53 proteins associated with the complement and coagulation systems were included in the analysis. Nine of those proteins were differentially abundant in subjects with asthma as compared to HC, and C3 was significantly higher in inadequately controlled asthma as compared to well-controlled asthma. Several proteins were associated with physiological tests assessing small airways. CONCLUSIONS: The study highlights the role of the local activation of the complement and coagulation systems in the small airway lining fluid in asthma and their association with both asthma control and small airway dysfunction. The findings highlight the potential of complement factors as biomarkers to identify different sub-groups among patients with asthma that could potentially benefit from a therapeutic approach targeting the complement system.

Neonatal endotoxin stimulation is associated with a long-term bronchiolar epithelial expression of innate immune and anti-allergic markers that attenuates the allergic response.

Allergic asthma is the most common phenotype of the pathology, having an early-onset in childhood and producing a Th2-driven airways remodeling process that leads to symptoms and pathophysiological changes. The avoidance of aeroallergen exposure in early life has been shown to prevent asthma, but without repeated success and with the underlying preventive mechanisms at the beginning of asthma far to be fully recognized. In the present study, we aimed to evaluate if neonatal LPS-induced boost in epithelial host defenses contribute to prevent OVA-induced asthma in adult mice. To this, we focused on the response of bronchiolar club cells (CC), which are highly specialized in maintaining the epithelial homeostasis in the lung. In these cells, neonatal LPS administration increased the expression of TLR4 and TNFα, as well as the immunodulatory/antiallergic proteins: club cell secretory protein (CCSP) and surfactant protein D (SP-D). LPS also prevented mucous metaplasia of club cells and reduced the epidermal growth factor receptor (EGFR)-dependent mucin overproduction, with mice displaying normal breathing patterns after OVA challenge. Furthermore, the overexpression of the epithelial Th2-related molecule TSLP was blunted, and normal TSLP and IL-4 levels were found in the bronchoalveolar lavage. A lower eosinophilia was detected in LPS-pretreated mice, along with an increase in phagocytes and regulatory cells (CD4+CD25+FOXP3+ and CD4+IL-10+), together with higher levels of IL-12 and TNFα. In conclusion, our study demonstrates stable asthma-preventive epithelial effects promoted by neonatal LPS stimulation, leading to the presence of regulatory cells in the lung. These anti-allergic dynamic mechanisms would be overlaid in the epithelium, favored by an adequate epidemiological environment, during the development of asthma.

IL-13 and IL-4, but not IL-5 nor IL-17A, induce hyperresponsiveness in isolated human small airways.

BACKGROUND: Specific inflammatory pathways are indicated to contribute to severe asthma, but their individual involvement in the development of airway hyperresponsiveness remains unexplored. OBJECTIVE: This experimental study in human small bronchi aimed to provide insight into which of the type 2 and type 17 cytokines cause hyperresponsiveness of airway smooth muscle. METHODS: Explanted small bronchi isolated from human lung tissue and human airway smooth muscle cells were treated for 2 and 1 day(s), respectively, with 100 ng/mL of IL-4, IL-5, IL-13, or IL-17A, and contractile responses, Ca2+ mobilization, and receptor expression were assessed. RESULTS: Treatment with IL-13 increased the potency of histamine, carbachol, and leukotriene D4 as contractile agonists. IL-4, but not IL-5 or IL-17A, also increased the potency of histamine. In human airway smooth muscle cells, IL-13 and IL-4, but not IL-5 and IL-17A, enhanced the histamine-induced Ca2+ mobilization that was accompanied with increased mRNA expression of histamine H1 and cysteinyl leukotriene CysLT1 receptors. RNA sequencing of isolated bronchi confirmed the IL-13-mediated upregulation of H1 and CysLT1 receptors, without showing an alteration of muscarinic M3 receptors. Dexamethasone had no effects on IL-13-induced hyperresponsiveness in human bronchi, the increased Ca2+ mobilization, or the enhanced receptor expression. In contrast, antagonism of the common receptor for IL-13 and IL-4 by the biologic dupilumab prevented the effects of both IL-13 and IL-4 in human bronchi and human airway smooth muscle cells. CONCLUSIONS: The glucocorticoid-insensitive hyperrresponsiveness in isolated human airways induced by IL-13 and IL-4 provides further evidence that the IL-4Rα pathway should be targeted as a new strategy for the treatment of airway hyperresponsiveness in asthma.

Exposure to lipopolysaccharide (LPS) reduces contractile response of small airways from GSTCD-/- mice.

INTRODUCTION: Genome-Wide Association Studies suggest glutathione S transferase C terminal domain (GSTCD) may play a role in development of Chronic Obstructive Pulmonary Disease. We aimed to define the potential role of GSTCD in airway inflammation and contraction using precision cut lung slice (PCLS) from wild-type (GSTCD+/+) and GSTCD knockout mice (GSTCD-/-). METHODS: PCLS from age and gender matched GSTCD+/+ and GSTCD-/- mice were prepared using a microtome. Contraction was studied after applying either a single dose of Methacholine (Mch) (1 µM) or different doses of Mch (0.001 to 100 µM). Each slice was then treated with lipopolysaccharide (LPS) or vehicle (PBS) for 24 hours. PCLS contraction in the same airway was repeated before and after stimulation. Levels of TNFα production was also measured. RESULTS: There were no differences in contraction of PCLS from GSTCD+/+ and GSTCD-/- mice in response to Mch (EC50 of GSTCD+/+ vs GSTCD-/- animals: 100.0±20.7 vs 107.7±24.5 nM, p = 0.855, n = 6 animals/group). However, after LPS treatment, there was a 31.6% reduction in contraction in the GSTCD-/- group (p = 0.023, n = 6 animals). There was no significant difference between PBS and LPS treatment groups in GSTCD+/+ animals. We observed a significant increase in TNFα production induced by LPS in GSTCD-/- lung slices compared to the GSTCD+/+ LPS treated slices. CONCLUSION: GSTCD knockout mice showed an increased responsiveness to LPS (as determined by TNFα production) that was accompanied by a reduced contraction of small airways in PCLS. These data highlight an unrecognised potential function of GSTCD in mediating inflammatory signals that affect airway responses.

Airway M Cells Arise in the Lower Airway Due to RANKL Signaling and Reside in the Bronchiolar Epithelium Associated With iBALT in Murine Models of Respiratory Disease.

Microfold (M) cells residing in the follicle-associated epithelium of mucosa-associated lymphoid tissues are specialized for sampling luminal antigens to initiate mucosal immune responses. In the past decade, glycoprotein 2 (GP2) and Tnfaip2 were identified as reliable markers for M cells in the Peyer's patches of the intestine. Furthermore, RANKL-RANK signaling, as well as the canonical and non-canonical NFκB pathways downstream, is essential for M-cell differentiation from the intestinal stem cells. However, the molecular characterization and differentiation mechanisms of M cells in the lower respiratory tract, where organized lymphoid tissues exist rarely, remain to be fully elucidated. Therefore, this study aimed to explore M cells in the lower respiratory tract in terms of their specific molecular markers, differentiation mechanism, and functions. Immunofluorescence analysis revealed a small number of M cells expressing GP2, Tnfaip2, and RANK is present in the lower respiratory tract of healthy mice. The intraperitoneal administration of RANKL in mice effectively induced M cells, which have a high capacity to take up luminal substrates, in the lower respiratory epithelium. The airway M cells associated with lymphoid follicles were frequently detected in the pathologically induced bronchus-associated lymphoid tissue (iBALT) in the murine models of autoimmune disease as well as pulmonary emphysema. These findings demonstrate that RANKL is a common inducer of M cells in the airway and digestive tracts and that M cells are associated with the respiratory disease. We also established a two-dimensional culture method for airway M cells from the tracheal epithelium in the presence of RANKL successfully. This model may be useful for functional studies of M cells in the sampling of antigens at airway mucosal surfaces.

An obligatory role for club cells in preventing obliterative bronchiolitis in lung transplants.

Obliterative bronchiolitis (OB) is a poorly understood airway disease characterized by the generation of fibrotic bronchiolar occlusions. In the lung transplant setting, OB is a pathological manifestation of bronchiolitis obliterans syndrome (BOS), which is a major impediment to long-term recipient survival. Club cells play a key role in bronchiolar epithelial repair, but whether they promote lung transplant tolerance through preventing OB remains unclear. We determined if OB occurs in mouse orthotopic lung transplants following conditional transgene-targeted club cell depletion. In syngeneic lung transplants club cell depletion leads to transient epithelial injury followed by rapid club cell-mediated repair. In contrast, allogeneic lung transplants develop severe OB lesions and poorly regenerate club cells despite immunosuppression treatment. Lung allograft club cell ablation also triggers the recognition of alloantigens, and pulmonary restricted self-antigens reported associated with BOS development. However, CD8+ T cell depletion restores club cell reparative responses and prevents OB. In addition, ex-vivo analysis reveals a specific role for alloantigen-primed effector CD8+ T cells in preventing club cell proliferation and maintenance. Taken together, we demonstrate a vital role for club cells in maintaining lung transplant tolerance and propose a new model to identify the underlying mechanisms of OB.

Microbial volatile communication in human organotypic lung models.

We inhale respiratory pathogens continuously, and the subsequent signaling events between host and microbe are complex, ultimately resulting in clearance of the microbe, stable colonization of the host, or active disease. Traditional in vitro methods are ill-equipped to study these critical events in the context of the lung microenvironment. Here we introduce a microscale organotypic model of the human bronchiole for studying pulmonary infection. By leveraging microscale techniques, the model is designed to approximate the structure of the human bronchiole, containing airway, vascular, and extracellular matrix compartments. To complement direct infection of the organotypic bronchiole, we present a clickable extension that facilitates volatile compound communication between microbial populations and the host model. Using Aspergillus fumigatus, a respiratory pathogen, we characterize the inflammatory response of the organotypic bronchiole to infection. Finally, we demonstrate multikingdom, volatile-mediated communication between the organotypic bronchiole and cultures of Aspergillus fumigatus and Pseudomonas aeruginosa.

Aggregation and Its Influence on the Immunomodulatory Activity of Synthetic Innate Defense Regulator Peptides.

There is increasing interest in developing cationic host defense peptides (HDPs) and their synthetic derivatives as antimicrobial, immunomodulatory, and anti-biofilm agents. These activities are often evaluated without considering biologically relevant concentrations of salts or serum; furthermore certain HDPs have been shown to aggregate in vitro. Here we examined the effect of aggregation on the immunomodulatory activity of a synthetic innate defense regulator peptide, 1018 (VRLIVAVRIWRR-NH2). A variety of salts and solutes were screened to determine their influence on 1018 aggregation, revealing that this peptide "salts out" of solution in an anion-specific and concentration-dependent manner. Furthermore, the immunomodulatory activity of 1018 was found to be inhibited under aggregation-promoting conditions. A series of 1018 derivatives were synthesized with the goal of disrupting this self-assembly process. Indeed, some derivatives exhibited reduced aggregation while maintaining certain immunomodulatory functions, demonstrating that it is possible to engineer optimized synthetic HDPs to avoid unwanted peptide aggregation.

Systematic Analysis of Cell-Type Differences in the Epithelial Secretome Reveals Insights into the Pathogenesis of Respiratory Syncytial Virus-Induced Lower Respiratory Tract Infections.

Lower respiratory tract infections from respiratory syncytial virus (RSV) are due, in part, to secreted signals from lower airway cells that modify the immune response and trigger airway remodeling. To understand this process, we applied an unbiased quantitative proteomics analysis of the RSV-induced epithelial secretory response in cells representative of the trachea versus small airway bronchiolar cells. A workflow was established using telomerase-immortalized human epithelial cells that revealed highly reproducible cell type-specific differences in secreted proteins and nanoparticles (exosomes). Approximately one third of secretome proteins are exosomal; the remainder are from lysosomal and vacuolar compartments. We applied this workflow to three independently derived primary human cultures from trachea versus bronchioles. A total of 577 differentially expressed proteins from control supernatants and 966 differentially expressed proteins from RSV-infected cell supernatants were identified at a 1% false discovery rate. Fifteen proteins unique to RSV-infected primary human cultures from trachea were regulated by epithelial-specific ets homologous factor. A total of 106 proteins unique to RSV-infected human small airway epithelial cells was regulated by the transcription factor NF-κB. In this latter group, we validated the differential expression of CCL20/macrophage-inducible protein 3α, thymic stromal lymphopoietin, and CCL3-like 1 because of their roles in Th2 polarization. CCL20/macrophage-inducible protein 3α was the most active mucin-inducing factor in the RSV-infected human small airway epithelial cell secretome and was differentially expressed in smaller airways in a mouse model of RSV infection. These studies provide insights into the complexity of innate responses and regional differences in the epithelial secretome participating in RSV lower respiratory tract infection-induced airway remodeling.

The Lymphatic Phenotype of Lung Allografts in Patients With Bronchiolitis Obliterans Syndrome and Restrictive Allograft Syndrome.

BACKGROUND: Chronic lung allograft dysfunction (CLAD), presenting as bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS) is the major limiting factor of long-term survival in lung transplantation. Its pathogenesis is still obscure. In BOS, persistent alloimmune injury and chronic airway inflammation are suggested. One of the main tasks of the lymphatic vessel (LV) system is the promotion of immune cell trafficking. The formation of new LVs has been shown to trigger chronic allograft rejection in kidney transplants. We therefore sought to address the role of lymphangiogenesis in CLAD. METHODS: Formalin-fixed paraffin-embedded tissue samples of 22 patients receiving a lung retransplantation due to BOS or RAS were collected. Lymphatic vessel density (LVD) was determined by immunohistochemical staining for podoplanin. Lung tissue obtained from 13 non-CLAD patients served as control. The impact of LVD on graft survival was assessed. RESULTS: Lymphatic vessel density in CLAD patients did not differ from those in control subjects (median number of LVs per bronchiole: 4.75 (BOS), 6.47 (RAS), 4.25 (control), P = 0.97). Moreover, the number of LVs was not associated with regions of cellular infiltrates (median number of LVs per bronchiole: with infiltrates, 5.00 (BOS), 9.00 (RAS), 4.00 (control), P = 0.62; without infiltrates, 4.5 (BOS), 0.00 (RAS), 4.56 (control), P = 0.74). Lymphatic vessel density did not impact the time to development of BOS or RAS in lung transplantation (low vs high LVD: 38.5 vs 86.0 months, P = 0.15 [BOS]; 60.5 vs 69.5 months, P = 0.80 [RAS]). CONCLUSIONS: Unlike chronic organ failure in kidney transplantation, lymphangiogenesis is not altered in CLAD patients. Our findings highlight unique immunological processes leading to BOS and RAS.

Effects of ceftaroline on the innate immune and on the inflammatory responses of bronchial epithelial cells exposed to cigarette smoke.

The tobacco smoking habit interferes with the innate host defence system against infections. Recurrent infections accelerated the functional respiratory decline. The present study assessed the effects of ceftaroline on TLR2 and TLR4 and on pro-inflammatory responses in airway epithelial cells (16HBE cell line and primary bronchial epithelial cells) with or without cigarette smoke extracts (CSE 10%). TLR2, TLR4, LPS binding and human beta defensin 2 (HBD2) were assessed by flow cytometry, NFkB nuclear translocation by western blot analysis, IL-8 and HBD2 mRNA by Real Time PCR; the localization of NFkB on the HBD2 and IL-8 promoters by ChiP Assay. CSE increased TLR4, TLR2 expression, LPS binding and IL-8 mRNA; CSE decreased HBD2 (protein and mRNA), activated NFkB and promoted the localization of NFkB on IL-8 promoter and not on HBD2 promoter. Ceftaroline counteracted the CSE effect on TLR2 expression, on LPS binding, on IL-8 mRNA, HBD2 and NFkB in 16HBE. The effects of ceftaroline on HBD2 protein and on IL-8 mRNA were confirmed in primary bronchial epithelial cells. In conclusion, ceftaroline is able to counteract the effects of CSE on the innate immunity and pro-inflammatory responses modulating TLR2, LPS binding, NFkB activation and activity, HBD2 and IL-8 expression in bronchial epithelial cells.

Apoptosis of the Tracheal Epithelium Can Increase the Number of Recipient Bone Marrow-Derived Myofibroblasts in Allografts and Exacerbate Obliterative Bronchiolitis After Tracheal Transplantation in Mice.

BACKGROUND: The long-term outcome of lung transplantation is impeded by the development of obliterative bronchiolitis (OB). We sought to investigate the relationship between the apoptosis of tracheal epithelial cells and bone marrow-derived myofibroblasts in the process of OB. METHODS: The mouse orthotopic tracheal transplant model was established. The allografts and syngrafts were harvested at 1, 2, 3, and 4 weeks after tracheal transplant. The percentage of tracheal lumen occlusion was assayed via histology and morphometry. Immunofluorescence staining was used to detect the apoptotic epithelial cells and recipient-derived myofibroblasts. The expression of SDF-1α and TGF-ß and the infiltrations of CD4 and CD8 T cells in the grafts were detected using immunohistochemical staining. RESULTS: We found that there were more apoptotic epithelia in the allograft group than in the syngraft group and that the level of tracheal lumen occlusion was higher at different time points. Moreover, the increase in the apoptosis of the tracheal epithelium occurred earlier than that of occlusion of the tracheal lumen. There were more myofibroblasts derived from the recipient's bone marrow and more CD4 and CD8 T cells in the allografts. The expression of SDF-1α and TGF-ß was higher in the epithelium from allografts than in those of the syngrafts. CONCLUSIONS: Our study indicated that the apoptotic tracheal epithelia in the OB model might increase the amount of myofibroblasts derived from the recipient's bone marrow. Therapeutic methods aimed at preventing apoptosis of the tracheal epithelium may improve the outcome of lung transplantation.

Anti-infective control in human bronchiolar epithelial cells by mucin phenotypic changes following uptake of N-acetyl-L-cysteine.

PURPOSE: Aspiration pneumonia is infection of the respiratory tract resulting from accumulation of sputum in the larynx. N-acetyl-L-cysteine (NAC) might regulate mucin (MUC) expression and activate inherent anti-infective system in bronchiolar epithelial cells after cellular uptake, and therefore, serve as the preventative agent for chronic lung disease including aspiration pneumonia. The purpose of this in vitro study was to evaluate the effect of uptake of NAC by human bronchiolar epithelial cells on bacterial infection and regulations of mucin expression in association with cellular redox status under co-culture with a representative pathogen for hospital- and community-acquired pneumonia, Streptococcus pneumoniae. MATERIALS AND METHODS: Human bronchiolar epithelial cells preincubated with or without 20 mM NAC for 3 h were co-cultured with or without bacteria for 8 h and evaluated with respect to cellular redox balance, expressions of various types of MUC, proinflammatory cytokines and mediators, and bacterial infection state by biochemical, genetic, and immunofluorescent assays. RESULTS: Markedly increased intracellular reactive oxygen species and oxidized glutathione levels plus increased release and expression of proinflammatory cytokines and mediators were observed in cells co-cultured with bacteria. These bacteria-induced cellular redox disturbance and proinflammatory events were prevented and alleviated by pretreatment with NAC. Cells co-cultured with bacteria did not increase expression of anti-infective membranous MUC4 but exhibited increases in gel-forming MUC5AC expression and bacterial infection. However, NAC-pretreated cells avoided bacterial infection along with enhancement of MUC4, but not MUC5AC, expression. CONCLUSION: Uptake of NAC by human bronchiolar epithelial cells prevented bacterial infection and upregulated membranous, but not gel-forming, MUC expression along with the increase in intracellular antioxidant level under co-culture conditions with S. pneumoniae.

Unsweetened natural cocoa has anti-asthmatic potential.

Unsweetened natural cocoa powder is enriched with nutraceutical abundance of anti-asthmatic compounds theobromine and theophylline. Cocoa powder, which is prepared after removal of the cocoa butter, contains about 1.9% theobromine and 0.21% caffeine. Anecdotal reports indicate that regular consumption of unsweetened natural cocoa powder (UNCP), a common practice in Ghana, West Africa, has the potential to reduce the tendency of asthmatic episodes. In the present paper we studied the effect of regular ingestion of aqueous extract of UNCP on hematological and histopathological changes that occur in ovalbumin (OVA)-sensitized guinea pigs. OVA-sensitized guinea pigs were challenged with aerosolized OVA 1 hour after ingestion of 300 mg/kg (low dose) or 600 mg/kg (high dose) of UNCP for 35 consecutive days. Histopathological and haematological changes in the OVA-sensitized guinea pigs were evaluated. Both negative and positive controls with distilled water and prednisolone, respectively, were used. OVA-sensitized guinea pigs demonstrated concentration-independent reduction in immune response to aerosolized OVA. There were no histo-architectural changes in the bronchiolar smooth muscles of the treated groups. Unsweetened natural cocoa powder has potential anti-asthmatic properties when administered orally at the doses tested.

A novel approach to partition central and peripheral airway nitric oxide.

BACKGROUND: Determining the site of airways inflammation may lead to the targeting of therapy. Nitric oxide (NO) is a biomarker of airway inflammation and can be measured at multiple exhalation flow rates to allow partitioning into bronchial (large/central airway maximal nitric oxide flux [J'awno]) and peripheral (peripheral/small airway/alveolar nitric oxide concentration [Cano]) airway contributions by linear regression. This requires a minimum of three exhalations. We developed a simple and practical method to partition NO. METHODS: In 29 healthy subjects (FEV1, 97% ± 3% predicted), 13 patients with asthma (FEV1, 90% ± 4% predicted), 14 patients with COPD (FEV1, 59% ± 3% predicted), and 12 patients with cystic fibrosis (CF) (FEV1, 60% ± 3% predicted), we measured the area under the curve of the NO concentration/exhalation time plot (AUC-NO) at exhalation flow rates of 50, 100, 200, and 300 mL/s. We determined the change of the total AUC-NO production (ΔAUC-NO) among the four different exhalation flow rates and compared these levels to Cano and J'awno indices measured conventionally by linear regression. RESULTS: The change in AUC-NO between increasing exhalation flow rates of 50 to 200 mL/s (ΔAUC-NO50-200) was strongly correlated with J'awno in all patient groups as follows: healthy subjects (r = 0.94, P < .001), patients with asthma (r = 0.98, P < .001), patients with COPD (r = 0.93, P < .001), and patients with CF (r = 0.74, P < .05). In all subjects, AUC-NO at an exhalation flow rate of 200 mL/s (AUC-NO200) correlated with Cano (r = 0.69, P < .01). CONCLUSIONS: The bronchial production of NO can be determined by measuring ΔAUC-NO50-200, whereas AUC-NO200 measures its peripheral concentration. This approach is simple, quick, and does not require sophisticated equipment or mathematical models.

Spatiotemporal quantification of cell dynamics in the lung following influenza virus infection.

Lung injury caused by influenza virus infection is widespread. Understanding lung damage and repair progression post infection requires quantitative spatiotemporal information on various cell types mapping into the tissue structure. Based on high content images acquired from an automatic slide scanner, we have developed algorithms to quantify cell infiltration in the lung, loss and recovery of Clara cells in the damaged bronchioles and alveolar type II cells (AT2s) in the damaged alveolar areas, and induction of pro-surfactant protein C (pro-SPC)-expressing bronchiolar epithelial cells (SBECs). These quantitative analyses reveal: prolonged immune cell infiltration into the lung that persisted long after the influenza virus was cleared and paralleled with Clara cell recovery; more rapid loss and recovery of Clara cells as compared to AT2s; and two stages of SBECs from Scgb1a1⁺ to Scgb1a1⁻. These results provide evidence supporting a new mechanism of alveolar repair where Clara cells give rise to AT2s through the SBEC intermediates and shed light on the understanding of the lung damage and repair process. The approach and algorithms in quantifying cell-level changes in the tissue context (cell-based tissue informatics) to gain mechanistic insights into the damage and repair process can be expanded and adapted in studying other disease models.

Critical role for IL-17A/F in the immunopathogenesis of obliterative airway disease induced by Anti-MHC I antibodies.

BACKGROUND: The IL-17 axis is implicated in pathogenesis of chronic rejection after human lung transplantation. Using a murine model of obliterative airway disease (OAD), we recently demonstrated that Abs to MHC class I antigens can induce immune responses to self-antigens that contributes to immunopathogenesis of chronic rejection. Using a murine model of OAD, we determined the role of IL-17 family members in induction of autoimmunity leading to OAD after ligation of MHC class I. METHODS: Anti-MHC class I or control antibodies (Abs) were administered intrabronchially to wild-type (WT) and IL-17a knock out (IL-17A-/-) C57BL/6. RESULTS: By day 30, anti-MHC I administered endobronchially in IL-17A-/- mice demonstrated significant reduction in cellular infiltration, a 36.8% reduction in CD4 T cells, 62.7% in CD11b macrophages, 37.5% in degree of fibrosis, 1.94 fold and 2.17 fold decrease in anti-KAT and anti-Col-V, respectively, when compared with wild-type mice. Analysis of lung infiltrating cells in anti-MHC I WT revealed increase in IL-17A (KAT:92+21,Col-V:103+19spm) and IL-17F (KAT:5.03%,Col-V:2.75%) secreting CD4+ T cells. However, administration of anti-MHC I in IL-17A-/- demonstrated increase only in IL-17F for KAT (13.70%) and Col-V (7.08%). Anti-IL-17(A-F) mAb administration after anti-MHC I abrogated OAD in both WT and IL-17A-/-. CONCLUSION: Our findings indicate that IL-17A and IL-17F secreted by CD4+Th17 cells specific to lung self-antigens are critical mediators of autoimmunity leading to the pathogenesis of OAD.

Corticosteroids and antigen avoidance decrease airway smooth muscle mass in an equine asthma model.

Recent studies suggest that airway smooth muscle remodeling is an early event in the course of asthma. Little is known of the effects of long-term antigen avoidance and inhaled corticosteroids on chronically established airway remodeling. We sought to measure the effects of inhaled corticosteroids and antigen avoidance on airway remodeling in the peripheral airways of horses with heaves, a naturally occurring asthma-like disease. Heaves-affected adult horses with ongoing airway inflammation and bronchoconstriction were treated with fluticasone propionate (with and without concurrent antigen avoidance) (n = 6) or with antigen avoidance alone (n = 5). Lung function and bronchoalveolar lavage were performed at multiple time points, and peripheral lung biopsies were collected before and after 6 and 12 months of treatment. Lung function improved more quickly with inhaled corticosteroids, but eventually normalized in both groups. Inflammation was better controlled with antigen avoidance. During the study period, corrected smooth muscle mass decreased from 12.1 ± 2.8 × 10(-3) and 11.3 ± 1.2 × 10(-3) to 8.3 ± 1.4 × 10(-3) and 7.9 ± 1.0 × 10(-3) in the antigen avoidance and fluticasone groups, respectively (P = 0.03). At 6 months, smooth muscle mass was significantly smaller compared with baseline only in the fluticasone-treated animals. The subepithelial collagen area was lower at 12 months than at baseline in both groups. During the study period, airway smooth muscle remodeling decreased by approximately 30% in both groups, although the decrease was faster in horses receiving inhaled corticosteroids. Inhaled corticosteroids may accelerate the reversal of smooth muscle remodeling, even if airway inflammation is better controlled with antigen avoidance.

Anti-malarial drug artesunate ameliorates oxidative lung damage in experimental allergic asthma.

Oxidative stress is a critical pathophysiological factor in the development of allergic airway inflammation, resulting in oxidative damage to lipids, proteins, and DNA. Our recent report revealed potent anti-inflammatory effects of the antimalarial drug artesunate in experimental allergic asthma. The present study investigated potential antioxidative effects of artesunate in a murine model of allergic asthma in comparison with dexamethasone, a potent corticosteroid. Mice were sensitized and challenged with ovalbumin and developed airway inflammation and oxidative lung damage. Artesunate markedly suppressed ovalbumin-induced increases in total cell, eosinophil, and neutrophil counts. In contrast, dexamethasone failed to inhibit neutrophil recruitment. Levels of the oxidative damage markers 8-isoprostane, 8-hydroxy-2-deoxyguanosine, and 3-nitrotyrosine were potently repressed by artesunate. However, dexamethasone showed weaker inhibitory effects on 3-nitrotyrosine production. Ovalbumin-induced increases in the expression of the pro-oxidants iNOS and NADPH oxidase (NOX1, 2, 3, and 4) were significantly abated by artesunate. Gene expression of regulatory subunits of NOX, p22phox and p67phox, was also reduced by artesunate. The expression and activities of the antioxidants superoxide dismutase and catalase were substantially reversed with artesunate in ovalbumin-challenged mice. Artesunate significantly enhanced nuclear levels of nuclear factor erythroid-2-related factor 2 (Nrf2) in lung tissues from ovalbumin-challenged mice and in TNF-α-stimulated human bronchial epithelial cells. Our findings implicate a potential therapeutic value for artesunate in the treatment of asthma via the amelioration of oxidative damage in allergic airways, and it may act by suppressing pro-oxidants and restoring the activities and expression of antioxidants via activation of Nrf2. Artesunate may be a potential novel anti-asthma drug capable of controlling both inflammation and oxidative damage in chronic severe asthma.