ABSTRACT
Background and objective
A new taxonomic and management approach, termed treatable traits, has been proposed for airway diseases including severe asthma. This study examined whether ...treatable traits could be identified using registry data and whether particular treatable traits were associated with future exacerbation risk.
Methods
The Australasian Severe Asthma Web‐Based Database (SAWD) enrolled 434 participants with severe asthma and a comparison group of 102 participants with non‐severe asthma. Published treatable traits were mapped to registry data fields and their prevalence was described. Participants were characterized at baseline and every 6 months for 24 months.
Results
In SAWD, 24 treatable traits were identified in three domains: pulmonary, extrapulmonary and behavioural/risk factors. Patients with severe asthma expressed more pulmonary and extrapulmonary treatable traits than non‐severe asthma. Allergic sensitization, upper‐airway disease, airflow limitation, eosinophilic inflammation and frequent exacerbations were common in severe asthma. Ten traits predicted exacerbation risk; among the strongest were being prone to exacerbations, depression, inhaler device polypharmacy, vocal cord dysfunction and obstructive sleep apnoea.
Conclusion
Treatable traits can be assessed using a severe asthma registry. In severe asthma, patients express more treatable traits than non‐severe asthma. Traits may be associated with future asthma exacerbation risk demonstrating the clinical utility of assessing treatable traits.
We assessed the prevalence of treatable traits in severe asthma compared with non‐severe asthma, and assessed the relationship between treatable traits and future exacerbation risk. We demonstrate the usefulness of the treatable traits approach in severe asthma and which specific treatable traits are predictive of future asthma attacks.
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Immunosuppression therapy after lung transplantation fails to prevent bronchiolitis obliterans syndrome (BOS) in many patients, primarily a disease of the small airways. We have reported that BOS is ...associated with a lack of suppression of cytotoxic mediators, and proinflammatory cytokines, in peripheral blood T, NKT-like (particularly CD8+) and NK cells. We also showed a loss of glucocorticoid receptor (GCR) in proinflammatory lymphocytes after transplant. It is unknown whether these proinflammatory lymphocytes target the small and/or large airways in BOS.
Blood, bronchoalveolar lavage, large proximal, and small distal airway brushings were collected from patients with BOS (n = 10), stable lung transplant patients (n = 18), and healthy aged-matched controls (n = 10). Intracellular cytotoxic mediators (perforin/granzyme B), proinflammatory cytokines (IFNγ/TNFα), and expression of GCR were determined in lymphocytes subsets from cultured blood using flow cytometry.
Increases in CD8 T cells, NKT-like cells, and NK cells were found in the small distal airways in BOS compared with stable patients and controls. An increase in perforin, granzyme B, IFNγ, TNFα, and a loss of GCR from these lymphocyte subsets was also found in BOS. GCR expression by CD8+ T cells from small airways correlated with FEV1 (R = 0.834, P = 0.039). Many of these changes significantly differed from those in the large airways.
BOS is associated with increased cytotoxic/proinflammatory CD8+ T, NKT-like, and NK cells in the small airways. Treatments that increase GCR in these lymphocyte subsets may improve graft survival.
Background and objective
Idiopathic, familial and secondary pulmonary arterial hypertension (PAH) are associated with reduced bone morphogenetic protein receptor type 2 (BMPR2) expression, and in ...some contexts, TGF‐β upregulation. Our aims were to assess BMPR2 gene therapy in a PAH mouse model and to assess the impact on TGF‐β signalling.
Methods
Using a targeted in vivo gene delivery approach, we assessed the impact of BMPR2 gene delivery in a transgenic mouse model in which PAH was first induced by doxycycline driven expression of a dominant negative BMPR2 mutant (R899X). We also assessed the impact of BMPR2 gene delivery on TGF‐β‐induced changes in cell signalling in human pulmonary vascular endothelial and smooth muscle cells.
Results
In the mouse model, changes in TGF‐β levels were not detected, but BMPR2 gene delivery reversed the increase in right ventricle systolic pressure (RVSP) and Fulton Index (FI), associated with a trend to increased pulmonary endothelial nitric oxide synthase (eNOS) gene expression. In vitro, BMPR2 gene transfer reduced TGF‐β effects on Smad2, Smad1/5/8 and Erk1/2 phosphorylation in human pulmonary arterial smooth muscle cells (HPASMC). BMPR2 was also found to upregulate nitric oxide (NO) production in lung derived human microvascular endothelial cells (HMVEC‐L).
Conclusion
This study provides further evidence that BMPR2 modulation may have therapeutic potential.
See Editorial, page 406
Upregulation of BMPR2 by gene delivery ameliorates PAH in a BMPR2‐mutant mouse model, increases nitric oxide production, and counteracts a number of TGF‐β‐induced effects on vascular cells in culture. This work adds to the evidence that BMPR2 upregulation has therapeutic potential in PAH.
See Editorial, page 406
Introduction: Pro-inflammatory CD8+ T cells are increased in the lungs and also in the peripheral circulation of both smokers and chronic obstructive pulmonary disease (COPD) patients. The reason for ...this is unclear but has been described as a spillover from cells in the lungs that may cause the systemic inflammation noted in COPD. We have recently shown an increase in steroid-resistant CD28nullCD8+ senescent lymphocytes in the lungs and peripheral blood in COPD. Leukotreine B4 (LB4) receptor 1 (BLTR1) is involved in recruitment of CD8+ T cells to sites of inflammation, and we hypothesized that it may be involved in the migration of these senescent lymphocytes from the lungs in COPD. Methods: Via flow cytometry and Western blot BLTR1, IFNγ, and TNFα expression were measured in peripheral blood, BAL, and large proximal and small distal airway CD28±, CD8± T, and NKT-like cells from COPD patients and healthy control subjects (±prednisolone) following in vitro stimulation. Chemotaxis of leucocyte subsets was determined (±LB4 ± prednisolone). Results: There was an increase in BLTR1-CD28nullCD8+ lymphocytes in the lungs and blood in patients with COPD compared with controls. BLTR1-CD28nullCD8+ T and NKT-like cells produce more IFN/TNF than BLTR+ cells and fail to migrate to LTB4. Treatment with 1 µM prednisolone in vitro resulted in upregulation of BLTR1 expression in pro-inflammatory CD28nullCD8+ cells and migration to LB4. Conclusions: Loss of BLTR1 is associated with an increased inflammatory potential of CD28nullCD8+ T cells and may allow these pro-inflammatory steroid-resistant cells to migrate to peripheral blood. Treatment strategies that upregulate BLTR1 may reduce systemic inflammation and associated co-morbidity in patients with COPD.
We reported defective efferocytosis associated with cigarette smoking and/or airway inflammation in chronic lung diseases, including chronic obstructive pulmonary disease, severe asthma, and ...childhood bronchiectasis. We also showed defects in phagocytosis of nontypeable
(NTHi), a common colonizer of the lower airway in these diseases. These defects could be substantially overcome with low-dose azithromycin; however, chronic use may induce bacterial resistance. The aim of the present study was therefore to investigate two novel macrolides-2'-desoxy-9-(S)-erythromycylamine (GS-459755) and azithromycin-based 2'-desoxy molecule (GS-560660)-with significantly diminished antibiotic activity against
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We tested their effects on efferocytosis, phagocytosis of NTHi, cell viability, receptors involved in recognition of apoptotic cells and/or NTHi (flow cytometry), secreted and cleaved intracellular IL-1β (cytometric bead array, immunofluorescence/confocal microscopy), and nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) using primary alveolar macrophages and THP-1 macrophages ± 10% cigarette smoke extract. Dose-response experiments showed optimal prophagocytic effects of GS-459755 and GS-560660 at concentrations of 0.5-1 µg/ml compared with our findings with azithromycin. Both macrolides significantly improved phagocytosis of apoptotic cells and NTHi (e.g., increases in efferocytosis and phagocytosis of NTHi: GS-459755, 23 and 22.5%,
= 0.043; GS-560660, 23.5 and 22%,
= 0.043, respectively). Macrophage viability remained >85% following 24 h exposure to either macrolide at concentrations up to 20 µg/ml. Secreted and intracellular-cleaved IL-1β was decreased with both macrolides with no significant changes in recognition molecules c-mer proto-oncogene tyrosine kinase; scavenger receptor class A, member 1; Toll-like receptor 2/4; or CD36. Particulate cytoplasmic immunofluorescence of NLRP3 inflammasome was also reduced significantly. We conclude that GS-459755 and GS-560660 may be useful for reducing airway inflammation in chronic lung diseases without inducing bacterial resistance.
Background
The AMAZES randomized controlled trial demonstrated that long‐term low‐dose azithromycin treatment reduces exacerbations of poorly controlled asthma, but the therapeutic mechanisms remain ...unclear. Dysregulation of the inflammatory tumour necrosis factor (TNF) pathway is implicated in asthma and could be suppressed by azithromycin. We aimed to determine the inflammatory and clinical associations of soluble TNF signalling proteins (TNF receptors TNFR 1 and 2, TNF) in sputum and serum, and to test the effect of 48 weeks of azithromycin vs placebo on TNF markers.
Methods
Sputum supernatant and serum TNFR1, TNFR2 (n = 142; 75 azithromycin‐treated, 67 placebo‐treated) and TNF (n = 48; 22 azithromycin‐treated, 26 placebo‐treated) were measured by ELISA in an AMAZES trial sub‐population at baseline and end of treatment. Baseline levels were compared between sputum inflammatory phenotypes, severe/non‐severe asthma and frequent/non‐frequent exacerbators. Effect of azithromycin on markers was tested using linear mixed models.
Results
Baseline sputum TNFR1 and TNFR2 were significantly increased in neutrophilic vs non‐neutrophilic asthma phenotypes, while serum markers did not differ. Sputum TNFR1 and TNFR2 were increased in severe asthma and correlated with poorer lung function, worse asthma control and increasing age. Serum TNFR1 was also increased in severe asthma. Sputum and serum TNFR2 were increased in frequent exacerbators. Azithromycin treatment significantly reduced sputum TNFR2 and TNF relative to placebo, specifically in non‐eosinophilic participants.
Conclusions
We demonstrate dysregulation of TNF markers, particularly in the airways, that relates to clinically important phenotypes of asthma including neutrophilic and severe asthma. Suppression of dysregulated TNF signalling by azithromycin could contribute to its therapeutic mechanism.
Increased sputum and serum TNF markers are associated with neutrophilic asthma, severe asthma and frequent exacerbation history. Azithromycin treatment reduces airway and systemic TNF markers, suggesting an anti‐inflammatory mechanism. Azithromycin effect on TNF markers is most pronounced in non‐eosinophilic asthma. Effect on serum but not sputum markers is related to sputum bacteria‐positive culture, linking antibiotic effect to modulation of systemic inflammation.
Abbreviations: AMAZES‐RCT, Asthma and Macrolides: The Azithromycin Efficacy and Safety study—Randomized Control Trial; TNF, tumor necrosis factor; TNFR, TNF receptor.
Recently identified molecular targets in pulmonary artery hypertension (PAH) include sphingosine‐1‐phosphate (S1P) and zinc transporter ZIP12 signaling. This study sought to determine linkages ...between these pathways, and with BMPR2 signaling. Lung tissues from a rat model of monocrotaline‐induced PAH and therapeutic treatment with bone marrow–derived endothelial‐like progenitor cells transduced to overexpress BMPR2 were studied. Multifluorescence quantitative confocal microscopy (MQCM) was applied for analysis of protein expression and localization of markers of vascular remodeling (αSMA and BMPR2), parameters of zinc homeostasis (zinc transporter SLC39A/ZIP family members 1, 10, 12 and 14; and metallothionein MT3) and S1P extracellular signaling (SPHK1, SPNS2, S1P receptor isoforms 1, 2, 3, 5) in 20–200 µm pulmonary microvessels. ZIP12 expression in whole lung tissue lysates was assessed by western blot. Spearman nonparametric correlations between MQCM readouts and hemodynamic parameters, Fulton index (FI), and right ventricular systolic pressure (RVSP) were measured. In line with PAH status, pulmonary microvessels in monocrotaline‐treated animals demonstrated significant (p < .05, n = 6 per group) upregulation of αSMA (twofold) and downregulation of BMPR2 (20%). Upregulated ZIP12 (92%), MT3 (57.7%), S1PR2 (54.8%), and S1PR3 (30.3%) were also observed. Significant positive and negative correlations were demonstrated between parameters of zinc homeostasis (ZIP12, MT3), S1P signaling (S1PRs, SPNS2), and vascular remodeling (αSMA, FI, RVSP). MQCM and western blot analysis showed that monocrotaline‐induced ZIP12 upregulation could be partially negated by BMPR2‐targeted therapy. Our results indicate that altered zinc transport/storage and S1P signaling in the monocrotaline‐induced PAH rat model are linked to each other, and could be alleviated by BMPR2‐targeted therapy.
Background:
The class III NAD-dependent histone deacetylase (HDAC) sirtuin 1 (SIRT1) is an important regulator of senescence, aging, and inflammation. SIRT1de-acetylates chromatin histones, thereby ...silencing inflammatory gene transcription. We have reported increased steroid-resistant senescent pro-inflammatory CD28nullCD8+ T cells in patients with chronic obstructive pulmonary disease (COPD). We hypothesized that SIRT1 is reduced in these cells in COPD, and that treatment with SIRT1 activators (resveratrol, curcumin) and agents preventing NAD depletion (theophylline) would upregulate SIRT1 and reduce pro-inflammatory cytokine expression in these steroid-resistant cells.
Methods:
Blood was collected from n = 10 COPD and n = 10 aged-matched controls. Expression of CD28, SIRT1, and pro-inflammatory cytokines was determined in CD8+ and CD8– T and natural killer T (NKT)-like cells cultured in the presence of ±1 µM prednisolone, ±5 mg/L theophylline, ±1 µM curcumin, ±25 µM resveratrol, using flow cytometry and immunofluorescence.
Results:
There was an increase in the percentage of CD28nullCD8+ T and NKT-like cells in COPD patients compared with controls. Decreased SIRT1 expression was identified in CD28nullCD8+T and NKT-like cells compared with CD28+ counterparts from both patients and controls (e.g. CD28null 11 ± 3% versus CD28+ 57 ± 9%). Loss of SIRT1 was associated with increased production of IFNγ and TNFα, steroid resistance, and disease severity. SIRT1 expression was upregulated in the presence of all drugs and was associated with a decrease in steroid resistance and IFNγ and TNFα production by CD28nullCD8+T and NKT-like cells. The presence of the SIRT1 inhibitor, EX-527 negated by 92 ± 12% (median ± SEM) the effect of the SIRT1 activator SRT720 on the percentage of CD8+ T cells producing IFNγ and TNFα.
Conclusions:
Steroid resistance in pro-inflammatory CD28nullCD8+ T and NKT-like cells is associated with decreased SIRT1 expression. Treatment with prednisolone, in combination with theophylline, curcumin or resveratrol increases SIRT1 expression, restores steroid sensitivity, and inhibits pro-inflammatory cytokine production from these cells and may reduce systemic inflammation in COPD.
The reviews of this paper are available via the supplemental material section.
Chronic obstructive pulmonary disease is a highly prevalent, complex disease, usually caused by cigarette smoke. It causes serious morbidity and mortality and costs the global community billions of ...dollars per year. While chronic inflammation, extracellular matrix destruction and increased airway epithelial cell apoptosis are reported in chronic obstructive pulmonary disease, the understanding of the basic pathogenesis of the disease is limited and there are no effective treatments. We hypothesized that the accumulation of apoptotic airway epithelial cells chronic obstructive pulmonary disease in could be due to defective phagocytic clearance by alveolar macrophages. There have been no previous studies of the phagocytic capacity of alveolar macrophages in chronic obstructive pulmonary disease using physiologically relevant apoptotic airway epithelial cells as phagocytic targets. We developed a phagocytosis assay whereby cultured 16HBE airway epithelial cells were induced to apoptosis with ultraviolet radiation and stained with mitotracker green. Alveolar macrophages from bronchoalveolar lavage from eight control and six chronic obstructive pulmonary disease subjects were analysed following 1.5 h incubation with apoptotic airway epithelial cells, then staining with macrophage marker anti CD33. CD33+/mitotracker green + events (i.e., alveolar macrophages which had phagocytosed apoptotic airway epithelial cells) were analysed using flow cytometry. Phagocytosis of polystyrene microbeads was investigated in parallel. A significantly reduced proportion of alveolar macrophages from chronic obstructive pulmonary disease subjects ingested apoptotic airway epithelial cells compared with controls (11.6 ± 4.1% for chronic obstructive pulmonary disease versus 25.6 ± 9.2% for control group). Importantly, the deficiency was not observed using polystyrene beads, suggesting that the failure to resolve epithelial damage in chronic obstructive pulmonary disease may result, at least partially, from specific defects in phagocytic ability of alveolar macrophages to ingest apoptotic airway epithelial cells.
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