Fugui Yan

P. aeruginosa Lipopolysaccharide-Induced MUC5AC and CLCA3 Expression Is Partly through Duox1 In Vitro and In Vivo

Background We have previously found that reactive oxygen species (ROS) are involved in Pseudomonas aeruginosa lipopolysaccharide (PA-LPS) induced MUC5AC in airway epithelial cells. Dual oxidase1 (Duox1), a member of NADPH oxidase(Nox), is known to be responsible for ROS production in respiratory tract epithelial cells. Our aim was to clarify whether Duox1 was also involved in the PA-LPS-induced MUC5AC and calcium dependent chloride channel 3(Clca3), another recognized marker of goblet cell hyperplasia and mucus hyper-production. Methods PA-LPS-induced Duox1 mRNA levels were examined in A549 cells, primary mouse tracheal epithelial cells (mTECS) and lung tissues of mice. Nox inhibitors diphenyleneiodonium chloride (DPI) and Duox1 siRNA were used to investigate whether Duox1 is involved in PA-LPS-induced MUC5AC and Clca3 expression both in vitro and in vivo. Results Duox1 is induced by PA-LPS in A549 cells, primary mTECs and lung tissues of mice. DPI significantly inhibited PA-LPS-induced up-regulation of Duox1, Muc5ac and Clca3 in primary mouse trachea epithelial cells and lung tissues of mice. Knockdown of Duox1 markedly inhibited PA-LPS-induced MUC5AC expression via a ROS-TGF-α cascade in A549 cells. Furthermore, DPI significantly inhibited PA-LPS-induced increases in inflammatory cells accumulated in mouse lungs. Conclusions We demonstrate for the first time that PA-LPS-induced MUC5AC and Clca3 expression is partly through Duox1, and provide supportive evidence for Duox1 as a potential target in treatments of mucin over-production diseases.

Interleukin-13-induced MUC5AC expression is regulated by a PI3K-NFAT3 pathway in mouse tracheal epithelial cells.

Interleukin-13 (IL-13) plays a critical role in asthma mucus overproduction, while the mechanisms underlying this process are not fully elucidated. Previous studies showed that nuclear factor of activated T cells (NFAT) is involved in the pathogenesis of asthma, but whether it can directly regulate IL-13-induced mucus (particularly MUC5AC) production is still not clear. Here we showed that IL-13 specifically induced NFAT3 activation through promoting its dephosphorylation in air-liquid interface (ALI) cultures of mouse tracheal epithelial cells (mTECs). Furthermore, both Cyclosporin A (CsA, a specific NFAT inhibitor) and LY294002 (a Phosphoinositide 3-kinase (PI3K) inhibitor) significantly blocked IL-13-induced MUC5AC mRNA and protein production through the inhibition of NFAT3 activity. We also confirmed that CsA could not influence the forkhead Box A2 (Foxa2) and mouse calcium dependent chloride channel 3 (mClca3) expression in IL-13-induced MUC5AC production, which both are known to be important in IL-13-stimulated mucus expression. Our study is the first to demonstrate that the PI3K-NFAT3 pathway is positively involved in IL-13-induced mucus production, and provided novel insights into the molecular mechanism of asthma mucus hypersecretion.

Angiotensin-converting Enzyme I/D Polymorphism is Associated with COPD Risk in Asian Population: Evidence from a Meta-analysis

Abstract Several molecular epidemiological studies were conducted in recent years to evaluate the risk of chronic obstructive pulmonary disease (COPD) associated with insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE). However, the results remain conflicting rather than conclusive. To derive a more precise estimation of association between ACE polymorphism and the risk of COPD, we performed a meta-analysis from all available relevant studies. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. There was a markedly positive association between the D allele or DD genotype and COPD risk in Asians (D vs. I: OR = 1.55, 95% CI = 1.407–2.44; DD vs. II: OR = 2.53, 95% CI = 1.65–3.89; DD vs. DI/II: OR = 2.09, 95% CI = 1.09–4.03), but this association was not observed in Europeans (D vs. I: OR = 0.93, 95% CI = 0.75–1.15; DD vs. II: OR = 0.86, 95% CI = 0.56–1.33; DD vs. DI/II: OR = 0.88, 95% CI = 0.63–1.23). Our meta-analysis provides strong evidence that D allele and DD homozygous might be significant genetic molecular markers for COPD susceptibility in Asians, but not for Europeans. Additional well-designed large studies were required for the validation of our results.

Proteomic analysis of sputum reveals novel biomarkers for various presentations of asthma

AbstractBackgroundIt is now recognized that asthma can present in different forms. Typically, asthma present with symptoms of wheeze, breathlessness and cough. Atypical forms of asthma such as cough variant asthma (CVA) or chest tightness variant asthma (CTVA) do not wheeze. We hypothesize that these different forms of asthma may have distinctive cellular and molecular features.Methods30 patients with typical or classical asthma (CA), 27 patients with CVA, 30 patients with CTVA, and 30 healthy control adults were enrolled in this prospective study. We measured serum IgE, lung function, sputum eosinophils, nitric oxide in exhaled breath (FeNO). We performed proteomic analysis of induced-sputum supernatants by mass spectrometry.ResultsThere were no significant differences in atopy and FEV1 among patients with CA, CVA, and CTVA. Serum IgE, sputum eosinophil percentages, FeNO, anxiety and depression scores were significantly increased in the three presentations of asthmatic patients as compared with healthy controls but there was no difference between the asthmatic groups. Comprehensive mass spectrometric analysis revealed more than a thousand proteins in the sputum from patients with CA, CVA, and CTVA, among which 23 secreted proteins were higher in patients than that in controls.ConclusionsPatients with CA, CVA, or CTVA share common clinical characteristics of eosinophilic airway inflammation. And more importantly, their sputum samples were composed with common factors with minor distinctions. These findings support the concept that these three different presentations of asthma have similar pathogenetic mechanism in terms of an enhanced Th2 associated with eosinophilia. In addition, this study identified a pool of novel biomarkers for diagnosis of asthma and to label its subtypes. Trial registrationhttp://www.chictr.org.cn (ChiCTR-OOC-15006221)

Nuclear erythroid 2 p45-related factor–2 Nrf2 ameliorates cigarette smoking-induced mucus overproduction in airway epithelium and mouse lungs

BACKGROUND AND OBJECTIVE Nuclear erythroid 2 p45-related factor-2 (Nrf2) is known to play important roles in airway disorders, whereas little has been investigated about its direct role in airway mucus hypersecretion. The aim of this study is to determine whether this factor could protect pulmonary epithelium and mouse airway from cigarette-induced mucus overproduction. METHODS Using genetic approaches, the role of Nrf2 on cigarette smoking extracts (CSE) induced MUC5AC expression was investigated in lung A549 cells. Nrf2 deficiency mice were smoked for various periods, and the airway inflammation and mucus production was characterized. RESULTS Acute smoking exposure induced expression of MUC5AC and Nrf2 in both A549 cells and mouse lungs. Genetic ablation of Nrf2 augmented, whereas overexpression of this molecule ameliorated CSE-induced expression of MUC5AC. Nrf2 knockout mice, after exposure to cigarette smoking, displayed enhanced airway inflammation and mucus production. CONCLUSION Nrf2 negatively regulated smoking-induced mucus production in vitro and in vivo, suggesting therapeutic potentials of this factor in airway diseases with hypersecreted mucus.

ATF3 is positively involved in particulate matter-induced airway inflammation in vitro and in vivo

Airborne particulate matter (PM) has been reported to be associated with a wide range of respiratory disorders. However, the mechanisms underlying PM-induced airway inflammation remain largely unknown. Generally, ATF3 negatively regulates pro-inflammatory cytokines production in response to TLR4 signaling. Here we first showed ATF3 has promoting effects in PM-induced airway inflammation in vitro an in vivo. We demonstrated PM significantly upregulated ATF3 expression in HBE cells and in mouse lung tissues. ATF3 siRNA markedly inhibited, while ATF3-recombinant over-expression plasmid significantly increased PM-induced IL-6 expression in cultured HBE cells, and PM-induced IL-6, CXCL2 expression as well as neutrophil infiltration, mucus over-production in the lung of ATF3-/- mice were all notably reduced relative to the wild-type littermates. Furthermore, we showed ATF3 mediated PM-induced inflammatory cytokines expression partly through NF-κB and AP-1 pathways. Our data further elucidates the mechanisms underlying PM-induced airway inflammation, and indicates ATF3 may function as different role in response to different stimuli.