Wing-Yan Heidi Wan’s research while affiliated with University of Leicester and other places

Background: Bronchial epithelial ciliary dysfunction is an important feature of asthma. We sought to determine the role in asthma of neutrophilic inflammation and NADPH oxidases in ciliary dysfunction. Methods: Bronchial epithelial ciliary function was assessed by video-microscopy in fresh ex vivo epithelial strips from asthmatics stratified by their sputum cell differentials and in cultures from healthy controls and asthmatics. Bronchial epithelial oxidative damage was determined by 8-oxo-dG expression. NOX/DUOX expression was assessed in bronchial epithelial cells by microarrays, with NOX4, DUOX1/2 expression assessed in bronchial biopsies. Ciliary dysfunction following NADPH oxidase inhibition, using GKT137831, was evaluated in fresh epithelial strips from asthmatics and a murine model of ovalbumin sensitisation and challenge. Results: Ciliary beat frequency was impaired in asthmatics with sputum neutrophilia (n=11) versus those without (n=10) (5.8 [0.6] versus 8.8 [0.5]Hz; P=0.003) and was correlated with sputum neutrophil count (r=-0.70; P<0.001). Primary bronchial epithelial cells expressed DUOX1/2 and NOX4. 8-oxo-dG and NOX4, were elevated in neutrophilic versus non-neutrophilic asthmatics, DUOX1 was elevated in both, and DUOX2 was elevated in non-neutrophilic asthma in vivo. In primary epithelial cultures ciliary dysfunction did not persist, although NOX4 expression and reactive oxygen species generation was increased from subjects with neutrophilic asthma. GKT137831 both improved ciliary function in ex vivo epithelial strips (n=13), relative to the intensity of neutrophilic inflammation, and abolished ciliary dysfunction in the murine asthma model without a reduction in inflammation. Conclusions: Ciliary dysfunction is increased in neutrophilic asthma associated with increased NOX4 expression and is attenuated by NADPH oxidase inhibition.

The mast cell localization to airway smooth muscle (ASM) bundle in asthma is important in the development of disordered airway physiology. Thymic stromal lymphopoietin (TSLP) is expressed by airway structural cells. Whether it has a role in the crosstalk between these cells is uncertain. We sought to define TSLP expression in bronchial tissue across the spectrum of asthma severity and to investigate the TSLP and TSLP receptor (TSLPR) expression and function by primary ASM and mast cells alone and in coculture. TSLP expression was assessed in bronchial tissue from 18 subjects with mild to moderate asthma, 12 with severe disease, and nine healthy control subjects. TSLP and TSLPR expression in primary mast cells and ASM was assessed by immunofluorescence, flow cytometry, and enzyme-linked immunosorbent assay, and its function was assessed by calcium imaging. The role of TSLP in mast cell and ASM proliferation, survival, differentiation, synthetic function, and contraction was examined. TSLP expression was increased in the ASM bundle in mild-moderate disease. TSLP and TSLPR were expressed by mast cells and ASM and were functional. Mast cell activation by TSLP increased the production of a broad range of chemokines and cytokines, but did not affect mast cell or ASM proliferation, survival, or contraction. TSLP expression by the bronchial epithelium and ASM was upregulated in asthma. TSLP promoted mast cell synthetic function, but did not contribute to other functional consequences of mast cell-ASM crosstalk.