Neutrophils from severe asthmatic patients induce epithelial to mesenchymal transition in healthy bronchial epithelial cells

Abstract

BackgroundAsthma is a heterogenous disease characterized by chronic inflammation and airway remodeling. An increase in the severity of airway remodeling is associated with a more severe form of asthma. There is increasing interest in the epithelial to mesenchymal transition process and mechanisms involved in the differentiation and repair of the airway epithelium, especially as they apply to severe asthma. Growing evidence suggests that Epithelial-Mesenchymal transition (EMT) could contribute to airway remodeling and fibrosis in asthma. Severe asthmatic patients with remodeled airways have a neutrophil driven inflammation. Neutrophils are an important source of TGF-β1, which plays a role in recruitment and activation of inflammatory cells, extracellular matrix (ECM) production and fibrosis development, and is a potent inducer of EMT.ObjectiveAs there is little data examining the contribution of neutrophils and/or their mediators to the induction of EMT in airway epithelial cells, the objective of this study was to better understand the potential role of neutrophils in severe asthma in regards to EMT.MethodsWe used an in vitro system to investigate the neutrophil-epithelial cell interaction. We obtained peripheral blood neutrophils from severe asthmatic patients and control subjects and examined for their ability to induce EMT in primary airway epithelial cells.ResultsOur data indicate that neutrophils from severe asthmatic patients induce changes in morphology and EMT marker expression in bronchial epithelial cells consistent with the EMT process when co-cultured. TGF-β1 levels in the culture medium of severe asthmatic patients were increased compared to that from co-cultures of non-asthmatic neutrophils and epithelial cells.Conclusions and clinical relevanceAs an inducer of EMT and an important source of TGF-β1, neutrophils may play a significant role in the development of airway remodeling and fibrosis in severe asthmatic airways.

TGF-β1 Signaling: Immune Dynamics of Chronic Kidney Diseases

“…Neutrophils are well-documented because of their aggravating role in inflammation ( 114 ), where neutrophil-to-lymphocyte ratio is a popular prognostic marker for estimating the mortality of CKD patients ( 115 ). Neutrophils can initiate and amplify inflammatory responses by releasing pro-inflammatory cytokines ( 114 , 116 ), and serves as a rich source of TGF-β1 in inflamed tissues ( 117 , 118 ). During inflammation, TGF-β1 facilitates the accumulation of neutrophils ( 119 , 120 ), therefore inhibiting TGF-β1 effectively alleviates neutrophil infiltration and inflammation ( 121 ).…”

Modern understanding of bronchial asthma with fixed airflow obstruction

“…Ремоделирование подразумевает под собой структурные изменения, такие как: увеличение массы гладких мышц, потеря целостности эпителия, утолщение базальной мембраны, субэпителиальный фиброз, гиперплазия подслизистой, снижение целостности хряща и повышение васкуляризации дыхательных путей [6]. Степень ремоделирования дыхательных путей положительно коррелирует с тяжестью заболевания [7].…”

Recombinant Pyrin Domain Protein Attenuates Airway Inflammation and Alleviates Epithelial-Mesenchymal Transition by Inhibiting Crosstalk Between TGFβ1 and Notch1 Signaling in Chronic Asthmatic Mice

“…They were cultured in DMEM containing 10% fetal bovine serum (Gibco BRL) and 1% penicillin/streptomycin (Gibco BRL) at 37 • C with 5% CO 2 . They were stimulated with recombinant human TGF-β1 (Abcam, ab166886) at 10 ng/mL for 48 h to induce EMT as previously described (Itoigawa et al, 2015;Haddad et al, 2019). During some experiments, BEAS−2B was pretreated with RPYD (5 µmol/L), TGFβ1 inhibitor SB431542 (10 µM, CST, #14775, United States), or NOTCH1 inhibitor DAPT (10 µM, CST, #15020, United States) for 6 h before TGF-β1 stimulation.…”

“…Studies have shown that TGFβ1 induces and promotes the occurrence of EMT (Haddad et al, 2019;Song et al, 2018). Therefore, TGFβ1 was used as an agonist to induce the occurrence of EMT in BEAS-2B cells.…”