Paradoxical effects of cigarette smoke and COPD on SARS-CoV-2 infection and disease.

BACKGROUND: How cigarette smoke (CS) and chronic obstructive pulmonary disease (COPD) affect severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection and severity is controversial. We investigated the effects of COPD and CS on the expression of SARS-CoV-2 entry receptor ACE2 in vivo in COPD patients and controls and in CS-exposed mice, and the effects of CS on SARS-CoV-2 infection in human bronchial epithelial cells in vitro. METHODS: We quantified: (1) pulmonary ACE2 protein levels by immunostaining and ELISA, and both ACE2 and/or TMPRSS2 mRNA levels by RT-qPCR in two independent human cohorts; and (2) pulmonary ACE2 protein levels by immunostaining and ELISA in C57BL/6 WT mice exposed to air or CS for up to 6 months. The effects of CS exposure on SARS-CoV-2 infection were evaluated after in vitro infection of Calu-3 cells and differentiated human bronchial epithelial cells (HBECs), respectively. RESULTS: ACE2 protein and mRNA levels were decreased in peripheral airways from COPD patients versus controls but similar in central airways. Mice exposed to CS had decreased ACE2 protein levels in their bronchial and alveolar epithelia versus air-exposed mice. CS treatment decreased viral replication in Calu-3 cells, as determined by immunofluorescence staining for replicative double-stranded RNA (dsRNA) and western blot for viral N protein. Acute CS exposure decreased in vitro SARS-CoV-2 replication in HBECs, as determined by plaque assay and RT-qPCR. CONCLUSIONS: ACE2 levels were decreased in both bronchial and alveolar epithelial cells from COPD patients versus controls, and from CS-exposed versus air-exposed mice. CS-pre-exposure potently inhibited SARS-CoV-2 replication in vitro. These findings urge to investigate further the controversial effects of CS and COPD on SARS-CoV-2 infection.

Noneosinophilic asthma in children: relation with airway remodelling.

Noneosinophilic asthma is increasingly recognised as an important clinical-pathological phenotype in adults. However, this entity has scarcely been investigated in children. In particular, it is unknown whether airway remodelling would develop in children with non-eosinophilic asthma to the same degree as in children with eosinophilic disease. We analysed bronchial biopsies from 80 children undergoing bronchoscopy for appropriate clinical indications: 21 with noneosinophilic asthma, 34 with eosinophilic asthma and 25 control children. Features of airway remodelling - basement membrane thickening, epithelial loss and angiogenesis - and immune activation - inflammatory infiltrate, interleukin (IL)-4, IL-5, transforming growth factor (TGF)-ß, TGF-ß receptor type II - were quantified by histology and immunohistochemistry. The main components of airway remodelling were present in children with noneosinophilic asthma just as in those with eosinophilic disease. Indeed, compared with control children, both noneosinophilic and eosinophilic asthmatic children had thickened basement membrane, increased epithelial loss and higher number of vessels. Moreover, in both groups of asthmatics, expression of IL-4 and IL-5 was increased, while that of TGF-ß receptor type II was reduced, compared with controls. This study demonstrates that structural changes typical of asthma develop in asthmatic children even in the absence of a prominent eosinophilic infiltrate, indicating that other mechanisms, besides eosinophilic inflammation, may promote airway remodelling early in life.

Markers of eosinophilic and neutrophilic inflammation in bronchoalveolar lavage of asthmatic and atopic children.

BACKGROUND: Recent studies performing fiberoptic bronchoscopy in children have improved our understanding of asthma pathophysiology. Eosinophilic, but also neutrophilic, inflammation has been described in asthma, but the relationship with atopy was incompletely investigated. The aim of this study is to examine inflammatory cells and mediators in children with asthma compared to the appropriate controls, i.e. atopic children without asthma and children with no atopy or asthma. Moreover, asthmatic children were analysed separately based on the presence of atopy and stratified by age. METHODS: We recruited 191 children undergoing fiberoptic bronchoscopy for appropriate indications: 91 asthmatics (aged 1.4-17 years), 44 atopics without asthma (1.6-17.8 years) and 56 nonasthmatic nonatopic controls (1.4-14 years). In bronchoalveolar lavage, total and differential cell counts and inflammatory mediators, including ECP, eotaxin, IL-8 and TNFalpha, were analysed. RESULTS: Eosinophils and ECP levels were increased in asthmatic children when compared to controls (P = 0.002 and P = 0.01, respectively), but also atopic children without asthma had increased ECP levels compared to controls (P = 0.0001). Among asthmatic children, eosinophils and ECP levels were not different between atopic and nonatopic individuals. Neither neutrophils nor the related mediators (IL-8 and TNFalpha) differed significantly in the three groups. This pattern of inflammation was observed in both preschool and school-aged asthmatic children. CONCLUSIONS: This study suggests that markers of eosinophilic, but not neutrophilic inflammation, are increased in asthmatic children and also in atopic children without asthma. Of interest, in asthmatic children, the activation of the eosinophilic response is not solely because of the presence of atopy.

Paradoxical effects of cigarette smoke and COPD on SARS-CoV2 infection and disease.

INTRODUCTION: How cigarette smoke (CS) and chronic obstructive pulmonary disease (COPD) affect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severity is controversial. We investigated the protein and mRNA expression of SARS-CoV-2 entry receptor ACE2 and proteinase TMPRSS2 in lungs from COPD patients and controls, and lung tissue from mice exposed acutely and chronically to CS. Also, we investigated the effects of CS exposure on SARS-CoV-2 infection in human bronchial epithelial cells. METHODS: In Cohort 1, ACE2-positive cells were quantified by immunostaining in FFPE sections from both central and peripheral airways. In Cohort 2, we quantified pulmonary ACE2 protein levels by immunostaining and ELISA, and both ACE2 and TMPRSS2 mRNA levels by RT-qPCR. In C57BL/6 WT mice exposed to air or CS for up to 6 months, pulmonary ACE2 protein levels were quantified by triple immunofluorescence staining and ELISA. The effects of CS exposure on SARS-CoV-2 infection were evaluated after 72hr in vitro infection of Calu-3 cells. After SARS-CoV-2 infection, the cells were fixed for IF staining with dsRNA-specific J2 monoclonal Ab, and cell lysates were harvested for WB of viral nucleocapsid (N) protein. Supernatants (SN) and cytoplasmic lysates were obtained to measure ACE2 levels by ELISA. RESULTS: In both human cohorts, ACE2 protein and mRNA levels were decreased in peripheral airways from COPD patients versus both smoker and NS controls, but similar in central airways. TMPRSS2 levels were similar across groups. Mice exposed to CS had decreased ACE2 protein levels in their bronchial and alveolar epithelia versus air-exposed mice exposed to 3 and 6 months of CS. In Calu3 cells in vitro, CS-treatment abrogated infection to levels below the limit of detection. Similar results were seen with WB for viral N protein, showing peak viral protein synthesis at 72hr. CONCLUSIONS: ACE2 levels were decreased in both bronchial and alveolar epithelial cells from uninfected COPD patients versus controls, and from CS-exposed versus air-exposed mice. CS-pre-treatment did not affect ACE2 levels but potently inhibited SARS-CoV-2 replication in this in vitro model. These findings urge to further investigate the controversial effects of CS and COPD on SARS-CoV2 infection.

Bronchial vascular remodelling in patients with COPD and its relationship with inhaled steroid treatment.

BACKGROUND: Only a few studies have evaluated microvascular changes and proangiogenetic mediators in the bronchial mucosa of patients with chronic obstructive pulmonary disease (COPD), and the results have been discordant. Furthermore, the role of inhaled corticosteroids (ICS) in COPD has not been extensively studied. A study was undertaken to evaluate vascular remodelling, its relationship with inflammatory cells and treatment effects in the bronchial mucosa of patients with COPD. METHODS: The study comprised three groups: (1) 10 non-treated patients with COPD (COPD); (2) 10 patients with COPD treated with nebulised beclomethasone dipropionate 1600-2400 mug daily (equivalent to 800-1200 mug via metered dose inhaler) (COPD/ICS); and (3) 8 control subjects (CS). Bronchial biopsies were evaluated for number and size of vessels and vascular area. Specimens were also examined for vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and transforming growth factor beta (TGF-beta) expression and inflammatory cell counts were performed. RESULTS: Vascular area, vessel size, VEGF+ cells, bFGF+ cells and TGF-beta+ cells were significantly increased in the COPD group compared with the COPD/ICS and CS groups (all p<0.05). In addition, bFGF+ cells were significantly increased in the COPD/ICS group compared with the CS group, and CD8+ and CD68+ cells were significantly increased in the COPD group compared with the COPD/ICS and CS groups (p<0.05). In the COPD group the VEGF+ cells correlated with the number of vessels (p<0.05), vascular area (p<0.01) and vessel size (p<0.05), and TGF-beta+ cells correlated significantly with vascular area (p<0.05). CONCLUSION: Bronchial vascular remodelling in patients with COPD is mainly related to morphological changes of the mucosal microvessels rather than to new vessel formation, and may be reduced in patients treated with steroids.

Increased activation of p38 MAPK in COPD.

Inflammation, oxidative stress and apoptosis, which are involved in chronic obstructive pulmonary disease (COPD) pathogenesis, may activate the p38 subgroup of mitogen-activated protein kinases (MAPKs). Therefore, the aim of the present study was to evaluate the expression of the phosphorylated, active form of p38 MAPK (phospho-p38) in the lungs of COPD patients. Surgical specimens were obtained from 18 smokers with COPD at different stages of disease severity, plus nine smoking and eight nonsmoking subjects with normal lung function. Phospho-p38+ cells were quantified by immunohistochemistry in both alveolar spaces and alveolar walls. Moreover, a Western blot analysis of phospho-p38 and total p38alpha isoform expressed by alveolar macrophages was performed. Phospho-p38+ alveolar macrophages and phospho-p38+ cells in alveolar walls were increased in patients with severe and mild/moderate COPD, compared with smoking and nonsmoking controls. Moreover, they were inversely correlated to values of forced expiratory volume in one second (FEV(1)) and FEV(1)/forced vital capacity. Western blot analysis showed that phosphorylated p38, but not the total p38alpha isoform, was specifically increased in alveolar macrophages from COPD patients. Activation of the p38 mitogen-activated protein kinase pathway appears to be involved in the pathogenesis of chronic obstructive pulmonary disease. The present findings suggest that this protein may be a suitable pharmacological target for therapeutic intervention.

Upregulation of basic fibroblast growth factor in smokers with chronic bronchitis.

The aim of the study was to investigate the expression of basic fibroblast growth factor (bFGF) and its receptor, fibroblast growth factor receptor (FGFR)-1, in the central airways of smokers with chronic bronchitis. The lobar bronchi from 17 subjects undergoing thoracotomy for solitary nodules were examined. All had a history of cigarette smoking, nine had symptoms of chronic bronchitis and airflow limitation, and eight were asymptomatic with normal lung function. Using immunohistochemical methods, bFGF and FGFR-1 expression in the total airway wall and the different airway compartments, i.e. bronchial glands, submucosal vessels and smooth muscle, was quantified. Moreover, to investigate the role of bFGF in angiogenesis, the number of submucosal vessels was quantified. Smokers with chronic bronchitis had an increased bFGF expression in the total airway wall compared with asymptomatic smokers, which was mainly due to bFGF upregulation in bronchial glands. By contrast, the expression of FGFR-1 and the number of submucosal vessels was similar in the two groups of subjects examined. In conclusion, smokers with chronic bronchitis have an increased expression of basic fibroblast growth factor in the central airways, which is mainly due to an increased expression in bronchial glands, suggesting the involvement of this growth factor in the pathogenesis of chronic bronchitis.

Transforming growth factor-beta type II receptor in pulmonary arteries of patients with very severe COPD.

A mild-to-moderate increase in pulmonary arterial pressure is often associated with severe chronic obstructive pulmonary disease (COPD). Transforming growth factor (TGF)-beta is a cytokine involved in the maintenance of integrity of vasculature. The aim of the study was to investigate whether the TGF-beta pathway might be involved in the development of pulmonary hypertension associated with COPD. Surgical specimens from 14 patients undergoing lung transplantation for very severe COPD (forced expiratory volume in one second 17 +/- 2% of the predicted value) and from seven donors were examined. The expression of TGF-beta1 and TGF-beta type II receptor (TGF-betaRII), cell proliferation index and structural changes in pulmonary arteries were quantified immunohistochemically. In severe COPD patients, increased expression of TGF-betaRII was observed in both the tunica media and intima, which was associated with a normal proliferation index in both layers. Conversely, significant thickening of the tunica intima, which was not present in the tunica media, was observed, suggesting that mechanisms other than cell proliferation may be involved in intimal thickening. In conclusion, in the pulmonary arteries of patients with severe chronic obstructive pulmonary disease, there is upregulation of transforming growth factor-beta type II receptor expression associated with a normal proliferation index. These findings suggest the activation of an antiproliferative pathway, which might explain the relatively low degree of pulmonary hypertension observed in these subjects.

Vascular endothelial growth factor up-regulation and bronchial wall remodelling in asthma.

BACKGROUND: There is increasing in vitro evidence to support a role for vascular endothelial growth factor (VEGF), a major regulator of angiogenesis, as a mediator of fibrosis associated with neovascularization. OBJECTIVE: We tested the hypothesis that VEGF is involved both in increased airway mucosal vascularity and in the subepithelial fibrosis of asthmatic patients. METHODS: Bronchial biopsies were performed in 24 asthmatic patients and eight healthy controls. Immunostaining, using computerized image analysis, was performed using monoclonal antibodies against VEGF(+) cells, type IV collagen, to outline the basement membrane thickness, and tryptase and EG2, to identify mast cells and eosinophils, respectively. RESULTS: The counts of VEGF(+) cells (P<0.05), mast cells and EG2(+) cells (both P<0.01) were higher in asthmatics than in controls. The number of vessels, the vascular area in the lamina propria, and the basement membrane thickness were significantly higher in asthmatics than in healthy volunteers (P<0.01). Moreover, in asthmatic patients, the number of VEGF(+) cells was significantly related to the number of vessels (P<0.01), to mast cells (P<0.01) and to basement membrane thickness (P<0.01). A colocalization study also revealed that mast cells were a relevant cellular source of VEGF. High doses of inhaled fluticasone propionate significantly reduced VEGF(+) cells (P<0.05), vessel number (P<0.05), vascular area (P<0.05) and basement membrane thickness (P<0.05) in a subgroup of asthmatic patients. CONCLUSIONS: This study shows that VEGF, in addition to being involved in the vascular component of airway remodelling, may play a role in the thickening of the basement membrane in asthma.

Decreased expression of TGF-beta type II receptor in bronchial glands of smokers with COPD.

BACKGROUND: The role of transforming growth factor-beta1 (TGF-beta1) in chronic obstructive pulmonary disease is still controversial, but it has been proposed that it may protect from mucus hypersecretion since it is able to downregulate mucin production. A study was undertaken to investigate the expression of TGF-beta1 and its type II receptor (TGF-beta RII) in the bronchial glands of smokers with COPD. METHODS: The expression of TGF-beta(1) and TGF-beta RII were examined immunohistochemically in the bronchial glands of 24 smokers undergoing lung resection for solitary peripheral nodules: 12 with airflow limitation (smokers with COPD) and 12 with normal lung function. RESULTS: The expression of TGF-beta1 in bronchial glands was similar in the two groups of subjects while that of TGF-beta RII was lower in smokers with COPD than in smokers with normal lung function (p=0.004). TGF-beta RII expression was inversely correlated with the values of Reid's index, a measure of gland size (p=0.02, r=-0.50). CONCLUSIONS: In the bronchial glands of smokers with COPD there is decreased expression of TGF-beta RII which is associated with bronchial gland enlargement. These findings support the view that the absence of TGF-beta signalling may induce structural changes in the bronchial glands which, in turn, may promote mucus hypersecretion.

Occludin dephosphorylation in early development of Xenopus laevis.

Using immunoblot and immunofluorescence analysis with a cross-reacting antiserum, we identified Xenopus laevis occludin as a 57-61 kDa antigen colocalized with cingulin in epithelial junctions of embryos. Occludin was completely extracted from unfertilized eggs and embryos with a solution containing 0.1% Triton X-100 and 1% NP40. Maternal occludin in unfertilized eggs migrated by SDS-PAGE as a 61 kDa protein. In fertilized eggs and in early cleavages up to blastula stage 8 it migrated as a series of polypeptides with 57-60 kDa. In gastrulae, neurulae and tailbud stage embryos, it migrated as a 57 kDa polypeptide. The electrophoretic mobility downshift was specifically reproduced by treatment of extracts with acid phosphatase, indicating that it is due to dephosphorylation. The correlation of occludin dephosphorylation with the de novo assembly of tight junction in native epithelia of Xenopus embryos suggests a possible role of occludin dephosphorylation in the events leading to tight junction assembly. To identify kinases which can phosphorylate occludin, recombinant chicken occludin (cytoplasmic domain) was subjected to in vitro phosphorylation. Occludin was phosphorylated on serine and threonine residues by protein kinase CK2 and p34cdc2/cyclin B complex, but was not significantly phosphorylated by mitogen-activated protein kinase, protein kinase CK1 and p38Syk tyrosine kinase. We noted that occludin sequences contain a motif matching the activation loop of the cytoplasmic domain of insulin receptor kinase.

Partial reversibility of airflow limitation and increased exhaled NO and sputum eosinophilia in chronic obstructive pulmonary disease.

We investigated the relationship between the reversibility of airflow limitation, the concentration of nitric oxide (NO) in exhaled air, and the inflammatory cells in the sputum of patients with stable chronic obstructive pulmonary disease (COPD). We examined nine normal healthy control subjects and 20 nonatopic patients with COPD. Ten patients had no reversibility of airflow limitation (increase in FEV(1) of < 12% and < 200 ml after 200 microg of inhaled salbutamol), and 10 patients had partial reversibility of airflow limitation (increase in FEV(1) of < 12% but > 200 ml after 200 microg of inhaled salbutamol). Exhaled NO levels were higher in COPD patients with partial reversibility of airflow limitation than in those with no reversibility of airflow limitation (median 24 [interquartile range 15.3 to 32] ppb versus 8.9 [4.6 to 14.7] ppb; p < 0.01). Compared with healthy control subjects, only COPD patients with partial reversibility of airflow limitation had increased concentrations of sputum eosinophils. We conclude that, in patients with stable COPD, even a partial bronchodilator response to inhaled salbutamol is associated with increased exhaled NO and sputum eosinophilia, suggesting that these patients may have a different response to treatment than do those without reversible airflow limitation.

Neutrophilic infiltration within the airway smooth muscle in patients with COPD.

BACKGROUND: COPD is an inflammatory disorder characterised by chronic airflow limitation, but the extent to which airway inflammation is related to functional abnormalities is still uncertain. The interaction between inflammatory cells and airway smooth muscle may have a crucial role. METHODS: To investigate the microlocalisation of inflammatory cells within the airway smooth muscle in COPD, surgical specimens obtained from 26 subjects undergoing thoracotomy (eight smokers with COPD, 10 smokers with normal lung function, and eight non-smoking controls) were examined. Immunohistochemical analysis was used to quantify the number of neutrophils, macrophages, mast cells, CD4+ and CD8+ cells localised within the smooth muscle of peripheral airways. RESULTS: Smokers with COPD had an increased number of neutrophils and CD8+ cells in the airway smooth muscle compared with non-smokers. Smokers with normal lung function also had a neutrophilic infiltration in the airway smooth muscle, but to a lesser extent. When all the subjects were analysed as one group, neutrophilic infiltration was inversely related to forced expiratory volume in 1 second (% predicted). CONCLUSIONS: Microlocalisation of neutrophils and CD8+ cells in the airway smooth muscle in smokers with COPD suggests a possible role for these cells in the pathogenesis of smoking induced airflow limitation.

Goblet cell hyperplasia and epithelial inflammation in peripheral airways of smokers with both symptoms of chronic bronchitis and chronic airflow limitation.

To quantify the number of goblet cells and inflammatory cells in the epithelium of peripheral airways in smokers with both symptoms of chronic bronchitis and chronic airflow limitation, we examined surgical specimens obtained from 25 subjects undergoing lung resection for localized pulmonary lesions: 10 smokers with symptoms of chronic bronchitis and chronic airflow limitation, six asymptomatic smokers with normal lung function, and nine nonsmoking control subjects. Peripheral airways were examined with histochemical methods to identify goblet cells and with immunohistochemical methods to identify total leukocytes (CD45(+) cells), neutrophils, macrophages, CD4(+) and CD8(+) cells in the epithelium. When compared with nonsmokers, smokers with both symptoms of chronic bronchitis and chronic airflow limitation had an increased number of goblet cells (p < 0.01), CD45(+) cells (p < 0. 01), macrophages (p < 0.05), and CD8(+) cells (p < 0.01) in the epithelium of peripheral airways. When all the smokers were grouped together, they showed an increased number of neutrophils (p < 0.05) along with an increased number of goblet cells, CD45(+) cells, macrophages and CD8(+) cells (p < 0.05) compared with nonsmokers. In conclusion, smokers with both symptoms of chronic bronchitis and chronic airflow limitation have an increased number of goblet cells and inflammatory cells in the epithelium of peripheral airways.

CD8+ve cells in the lungs of smokers with chronic obstructive pulmonary disease.

Previous studies have shown an increased number of inflammatory cells and, in particular, CD8+ve cells in the airways of smokers with chronic obstructive pulmonary disease (COPD). In this study we investigated whether a similar inflammatory process is also present in the lungs, and particularly in lung parenchyma and pulmonary arteries. We examined surgical specimens from three groups of subjects undergoing lung resection for localized pulmonary lesions: nonsmokers (n = 8), asymptomatic smokers with normal lung function (n = 6), and smokers with COPD (n = 10). Alveolar walls and pulmonary arteries were examined with immunohistochemical methods to identify neutrophils, eosinophils, mast cells, macrophages, and CD4+ve and CD8+ve cells. Smokers with COPD had an increased number of CD8+ve cells in both lung parenchyma (p < 0.05) and pulmonary arteries (p < 0.001) as compared with nonsmokers. CD8+ve cells were also increased in pulmonary arteries of smokers with COPD as compared with smokers with normal lung function (p < 0.01). Other inflammatory cells were no different among the three groups. The number of CD8+ve cells in both lung parenchyma and pulmonary arteries was significantly correlated with the degree of airflow limitation in smokers. These results show that an inflammatory process similar to that present in the conducting airways is also present in lung parenchyma and pulmonary arteries of smokers with COPD.

Direct effects of interleukin-13 on signaling pathways for physiological responses in cultured human airway smooth muscle cells.

Numerous studies have suggested an important role for the Th2 cytokines interleukin (IL)-13 and IL-4 in the development of allergic asthma. We tested the hypothesis that IL-13 and IL-4 have direct effects on cultured airway smooth muscle cells (HASM). Using RT-PCR, we showed that HASM cells express transcripts for IL-4alpha, IL-13RalphaI, and IL-13RalphaII, but not for the common IL-2Rgamma chain. We then analyzed the capacity of the two cytokines to activate signaling pathways in HASM cells. Both IL-13 and IL-4 caused STAT-6 phosphorylation, but the time course was different between the two cytokines, with peak effects occurring 15 min after addition of IL-4 and 1 h after addition of IL-13. Effects on signaling were observed at cytokine concentrations as low as 0.3 ng/ml. IL-4 and IL-13 also caused phosphorylation of ERK MAP kinase. As suggested by the signaling studies, the biological responses of the two cytokines were also different. We used magnetic twisting cytometry to measure cell stiffness of HASM cells and tested the capacity of IL-4 and IL-13 to interfere with the reductions in cell stiffness induced by the beta-agonist isoproterenol (ISO). IL-13 (50 ng/ml for 24 h), but not IL-4, significantly reduced beta-adrenergic responsiveness of HASM cells, and the MEK inhibitor U0126 significantly reduced the effects of IL-13 on ISO-induced changes in cell stiffness. We propose that these direct effect of IL-13 on HASM cells may contribute at least in part to the airway narrowing observed in patients with asthma.