scholarly journals Th1/17-Biased Inflammatory Environment Associated with COPD Alters the Response of Airway Epithelial Cells to Viral and Bacterial Stimuli

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Yifan Chen ◽  
Rakesh K. Kumar ◽  
Paul S. Thomas ◽  
Cristan Herbert
Keyword(s):  
Epithelial Cells ◽  
Proinflammatory Cytokines ◽  
Bacterial Infections ◽  
Respiratory Infections ◽  
Airway Epithelial Cells ◽  
Poly I:C ◽  
Chronic Obstructive ◽  
Airway Epithelial ◽  
Obstructive Pulmonary Disease ◽  
Enhanced Expression

Chronic obstructive pulmonary disease (COPD) is characterized by airway inflammation associated with a Th1/17-biased cytokine environment. Acute exacerbations of COPD (AECOPD) are most often triggered by respiratory infections, which elicit an exaggerated inflammatory response in these patients, via poorly defined mechanisms. We investigated the responses of airway epithelial cells (AECs) to infective stimuli in COPD and the effects of the Th1/17-biased environment on these responses. Cytokine expression was assessed following exposure to virus-like stimuli (poly I:C or imiquimod) or bacterial LPS. The effects of pretreatment with Th1/17 cytokines were evaluated in both primary AECs and the Calu-3 AEC cell line. We found that poly I:C induced increased expression of the proinflammatory cytokines IL1β, IL6, CXCL8, and TNF and IFN-β1 in AECs from both control subjects and COPD patients. Expression of IL1β in response to all 3 stimuli was significantly enhanced in COPD AECs. Primary AECs pretreated with Th1/17 cytokines exhibited enhanced expression of mRNA for proinflammatory cytokines in response to poly I:C. Similarly, Calu-3 cells responded to virus-like/bacterial stimuli with increased expression of proinflammatory cytokines, and a Th1/17 environment significantly enhanced their expression. Furthermore, increased expression of pattern recognition receptors for viruses (TLR3, TLR7, IFIH1, and DDX58) was induced by Th1/17 cytokines, in both primary AECs and Calu-3 cells. These findings suggest that the Th1/17-biased environment associated with COPD may enhance the proinflammatory cytokine response of AECs to viral and bacterial infections and that increased signaling via upregulated receptors may contribute to exaggerated inflammation in virus-induced AECOPD.

scholarly journals In vivo function of airway epithelial TLR2 in host defense against bacterial infection

2011 ◽  
Vol 300 (4) ◽  
pp. L579-L586 ◽  
Author(s):  
Qun Wu ◽  
Di Jiang ◽  
Maisha N. Minor ◽  
Richard J. Martin ◽  
Hong Wei Chu
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Epithelial Cells ◽  
Bacterial Infections ◽  
Airway Epithelial Cells ◽  
Chronic Obstructive ◽  
Airway Epithelial ◽  
Tlr2 Expression ◽  
Obstructive Pulmonary Disease ◽  
Tlr2 Signaling

Decreased Toll-like receptor 2 (TLR2) expression has been reported in patients with chronic obstructive pulmonary disease and in a murine asthma model, which may predispose the hosts to bacterial infections, leading to disease exacerbations. Since airway epithelial cells serve as the first line of respiratory mucosal defense, the present study aimed to reveal the role of airway epithelial TLR2 signaling to lung bacterial [i.e., Mycoplasma pneumoniae (Mp)] clearance. In vivo TLR2 gene transfer via intranasal inoculation of adenoviral vector was performed to reconstitute TLR2 expression in airway epithelium of TLR2−/−BALB/c mice, with or without ensuing Mp infection. TLR2 and lactotransferrin (LTF) expression in airway epithelial cells and lung Mp load were assessed. Adenovirus-mediated TLR2 gene transfer to airway epithelial cells of TLR2−/−mice reconstituted 30–40% TLR2 expression compared with TLR2+/+cells. Such airway epithelial TLR2 reconstitution in TLR2−/−mice significantly reduced lung Mp load (an appropriate 45% reduction), coupled with elevated LTF expression. LTF expression in mice was shown to be mainly dependent on TLR2 signaling in response to Mp infection. Exogenous human LTF protein dose-dependently decreased lung bacterial load in Mp-infected TLR2−/−mice. In addition, human LTF protein directly dose-dependently decreased Mp levels in vitro. These data indicate that reconstitution of airway epithelial TLR2 signaling in TLR2−/−mice significantly restores lung defense against bacteria (e.g., Mp) via increased lung antimicrobial protein LTF production. Our findings may offer a deliverable approach to attenuate bacterial infections in airways of asthma or chronic obstructive pulmonary disease patients with impaired TLR2 function.

scholarly journals ACE2 Expression is elevated in Airway Epithelial Cells from aged and male donors but reduced in asthma

2020 ◽  
Author(s):  
Peter Wark ◽  
Prabuddha Pathinyake ◽  
Gerard Kaiko ◽  
Kristy Nichol ◽  
Ayesha Ali ◽  
...  
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Serine Proteases ◽  
Airway Epithelial Cells ◽  
Lower Airway ◽  
Chronic Obstructive ◽  
Airway Epithelial ◽  
Obstructive Pulmonary Disease ◽  
Protein Levels ◽  
Asthma Patients

Rationale: COVID-19 is complicated by acute lung injury, and death in some individuals. It is caused by SARS-CoV-2 that requires the ACE2 receptor and serine proteases to enter airway epithelial cells (AECs). Objective: To determine what factors are associated with ACE2 expression particularly in patients with asthma and chronic obstructive pulmonary disease (COPD). Methods: We obtained upper and lower AECs from 145 people from two independent cohorts, aged 2-89, Newcastle (n=115), and from Perth (n= 30) Australia. The Newcastle cohort was enriched with people with asthma (n=37) and COPD (n=38). Gene expression for ACE2 and other genes potentially associated with SARS-CoV-2 cell entry were assessed by quantitative PCR, protein expression was confirmed with immunohistochemistry on endobronchial biopsies and cultured AECs. Results: Increased gene expression of ACE2 was associated with older age (p=0.02) and male sex (p=0.03), but not pack-years smoked. When we compared gene expression between adults with asthma, COPD and healthy controls, mean ACE2 expression was lower in asthma (p=0.01). Gene expression of furin, a protease that facilitates viral endocytosis, was also lower in asthma (p=0.02), while ADAM-17, a disintegrin that cleaves ACE2 from the surface was increased (p=0.02). ACE2 protein levels were lower in endobronchial biopsies from asthma patients. Conclusions: Increased ACE2 expression occurs in older people and males. Asthma patients have reduced expression. Altered ACE2 expression in the lower airway may be an important factor in virus tropism and may in part explain susceptibility factors and why asthma patients are not over-represented in those with COVID-19 complications.

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