| 1. |
- Fakih, Dalia, et al.
(author)
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Attached stratified mucus separates bacteria from the epithelial cells in COPD lungs
- 2018
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In: Jci Insight. - : American Society for Clinical Investigation. - 2379-3708. ; 3:17
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Journal article (peer-reviewed)abstract
- The respiratory tract is normally kept essentially free of bacteria by cilia-mediated mucus transport, but in chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF), bacteria and mucus accumulates instead. To address the mechanisms behind the mucus accumulation, the proteome of bronchoalveolar lavages from COPD patients and mucus collected in an elastase-induced mouse model of COPD was analyzed, revealing similarities with each other and with the protein content in colonic mucus. Moreover, stratified laminated sheets of mucus were observed in airways from patients with CF and COPD and in elastase-exposed mice. On the other hand, the mucus accumulation in the elastase model was reduced in Muc5b-KO mice. While mucus plugs were removed from airways by washing with hypertonic saline in the elastase model, mucus remained adherent to epithelial cells. Bacteria were trapped on this mucus, whereas, in non-elastase-treated mice, bacteria were found on the epithelial cells. We propose that the adherence of mucus to epithelial cells observed in CF, COPD, and the elastase-induced mouse model of COPD separates bacteria from the surface cells and, thus, protects the respiratory epithelium.
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| 2. |
- McCrae, Cristopher
(author)
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Host-Virus Interactions in Asthma and COPD
- 2018
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Doctoral thesis (other academic/artistic)abstract
- Asthma and chronic obstructive pulmonary disease (COPD) are associated with periods of worsened symptoms, known as exacerbations. Severe exac-erbations can result in hospitalisation, irreversible decline of the disease and sometimes death. Thus, exacerbations are a major cause of morbidity, mortality and healthcare cost. Treatment or prevention of exacerbations is an area of unmet medical need as the current standard of care has insuffi-cient impact on exacerbation frequency and severity. Respiratory viral infections are hypothesized to be important triggers of exacerbations. It has been shown that 41-95% of asthma exacerbations and 22-57% of COPD exacerbations are associated with a respiratory virus in-fection, the most common agent being human rhinovirus (RV). Other vi-ruses frequently associated with exacerbations include respiratory syncytial virus and influenza. Prevention or attenuation of respiratory virus infec-tions could therefore have significant impact on exacerbation frequency and severity. The mechanisms by which viruses trigger exacerbations are poorly un-derstood, although there is evidence for defective anti-viral interferon (IFN) responses in cells from patients with asthma and COPD. Further investiga-tion of host-virus interactions and their impact on underlying airway dis-ease, may lead to novel therapeutic targets for the prevention of exacerba-tions. We investigated host-virus interactions in asthma and COPD through a multi-faceted approach. First, we performed an in vitro functional ge-nomics screen using RNA interference (RNAi), to identify targets that are essential for RV replication in primary normal human bronchial epithelial cells. Second, we evaluated the efficacy of inhaled IFNβ-1a for the preven-tion of severe asthma exacerbations in a Phase 2 trial. Finally, we per-formed an observational, longitudinal study in COPD patients to investi-gate the relationship between exacerbations, viral and bacterial infections, air pollution and anti-microbial peptides (AMPs). In the first study, we identified lanosterol synthase (LSS) as a potential therapeutic target which, when inhibited, blocks RV replication and en-hances the RV-induced IFNβ response. We discovered that the mechanism of this effect was related to the induction of a regulatory sterol, 24(S),25 epoxycholesterol. In our phase 2 trial (INEXAS), we found that inhaled IFNβ-1a did not prevent the occurrence of severe asthma exacerbations, but improved peak expiratory flow (PEF). In an exploratory analysis, we also identified poten-tial responder subgroups, based on blood eosinophil counts or serum inter-leukin (IL)-18 levels. In our COPD cohort, we found that both viral infections and increases in ambient air pollution were associated with exacerbations. Viral exacerba-tions were strongly associated with upregulation of the IFN response bi-omarkers, CXCL10, CXCL11 and IFNγ. We went on to discover that the levels of beta-defensin 2 (hBD-2), an AMP expressed by the lung epitheli-um, is reduced in the sputum of patients who experienced exacerbations, and further found an association between low hBD-2 levels at exacerbation and the presence of a respiratory virus. The studies presented in this thesis have identified and evaluated key components of host-virus interactions and applied those to the context of asthma and COPD. In all cases, we found the IFN response to be central, not only to the events that occur inside the virus-infected cell, but also to the downstream consequences of infection at the tissue and organ level, likely playing a key role in both anti-bacterial and anti-viral host defense. Despite the extraordinary complexity of the interaction between the virus and its host, this thesis demonstrates that key drivers of this interplay can be identified, manipulated and, hopefully, developed into future medicines for the prevention of asthma and COPD exacerbations.
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| 3. |
- McCrae, Cristopher, et al.
(author)
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INEXAS: A Phase 2 Randomized Trial of On-demand Inhaled Interferon Beta-1a in Severe Asthmatics
- 2021
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In: Clinical and Experimental Allergy. - : Wiley. - 0954-7894 .- 1365-2222. ; 51:2, s. 273-283
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Journal article (peer-reviewed)abstract
- Background: Upper respiratory tract infections (URTIs) are important triggers for asthma exacerbations. We hypothesized that inhalation of the anti-viral cytokine, interferon (IFN)-β, during URTI, could prevent these exacerbations. Objective: To evaluate the efficacy of on-demand inhaled IFN-β1a (AZD9412) to prevent severe asthma exacerbations following symptomatic URTI. Methods: This was a randomized, double-blind, placebo-controlled trial in which patients with severe asthma (GINA 4-5; n=121) reporting URTI symptoms were randomized to 14days of once-daily nebulized AZD9412 or placebo. The primary endpoint was severe exacerbations during treatment. Secondary endpoints included 6-item asthma control questionnaire (ACQ-6) and lung function. Exploratory biomarkers included IFN-response markers in serum and sputum, blood leucocyte counts and serum inflammatory cytokines. Results: Following a pre-planned interim analysis, the trial was terminated early due to an unexpectedly low exacerbation rate. Asthma worsenings were generally mild and tended to peak at randomization, possibly contributing to the lack of benefit of AZD9412 on other asthma endpoints. Numerically, AZD9412 did not reduce severe exacerbation rate, ACQ-6, asthma symptom scores or reliever medication use. AZD9412 improved lung function (morning peak expiratory flow; mPEF) by 19.7 L/min. Exploratory post hoc analyses indicated a greater mPEF improvement by AZD9412 in patients with high blood eosinophils (>0.3×109/L) at screening and low serum interleukin-18 relative change at pre-treatment baseline. Pharmacodynamic effect of AZD9412 was confirmed using IFN-response markers. Conclusions & Clinical Relevance: Colds did not have the impact on asthma patients that was expected and, due to the low exacerbation rate, the trial was stopped early. On-demand AZD9412 treatment did not numerically reduce the number of exacerbations, but did attenuate URTI-induced worsening of mPEF. Severe asthma patients with high blood eosinophils or low serum interleukin-18 response are potential subgroups for further investigation of inhaled IFN-β1a. @2020 AstraZeneca. International Journal of Cosmetic Science published by John Wiley & Sons
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| 4. |
- McCrae, Cristopher, et al.
(author)
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Lanosterol Synthase Regulates Human Rhinovirus Replication in Human Bronchial Epithelial Cells
- 2018
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In: American Journal of Respiratory Cell and Molecular Biology. - 1044-1549. ; 59:6, s. 713-722
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Journal article (peer-reviewed)abstract
- Human rhinovirus (RV) infections are a significant risk factor for exacerbations of asthma and chronic obstructive pulmonary disease. Thus, approaches to prevent RV infection in such patients would give significant benefit. Through RNA interference library screening, we identified lanosterol synthase (LSS), a component of the cholesterol biosynthetic pathway, as a novel regulator of RV replication in primary normal human bronchial epithelial cells. Selective knock down of LSS mRNA with short interfering RNA inhibited RV2 replication in normal human bronchial epithelial cells. Small molecule inhibitors of LSS mimicked the effect of LSS mRNA knockdown in a concentration-dependent manner. We further demonstrated that the antiviral effect is not dependent on a reduction in total cellular cholesterol but requires a 24-hour preincubation with the LSS inhibitor. The rank order of antiviral potency of the LSS inhibitors used was consistent with LSS inhibition potency; however, all compounds showed remarkably higher potency against RV compared with the LSS enzyme potency. We showed that LSS inhibition led to an induction of 24(S),25 epoxycholesterol, an important regulator of the sterol pathway. We also demonstrated that LSS inhibition led to a profound increase in expression of the innate antiviral defense protein, IFN-beta. We found LSS to be a novel regulator of RV replication and innate antiviral immunity and identified a potential molecular mechanism for this effect, via induction of 24(S),25 epoxycholesterol. Inhibition of LSS could therefore be a novel therapeutic target for prevention of RV-induced exacerbations.
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