The association between eosinophilic exacerbation and eosinophilic levels in stable COPD.

BACKGROUND: Blood eosinophil count may predict treatment response in patients with chronic obstructive pulmonary disease (COPD) during acute exacerbations (AE). However, the ability and thresholds of blood eosinophil counts in stable status to predict eosinophilic AECOPD have not been completely investigated. METHODS: This was a retrospective multicenter study performed January 2010 to December 2014. COPD subjects hospitalized with exacerbations, were included. Blood samples were obtained at the time of AE and stable disease at outpatient clinic before or after admission. We identified a blood eosinophil count cut-off point at stable COPD, either taken as a percentage or as absolute value, for identification of eosinophilic exacerbation. RESULTS: There was significant positive correlation of eosinophil counts between stable COPD and AECOPD. The best cut-off value of blood eosinophil count in stable status for the prediction of eosinophilic COPD exacerbation based on blood eosinophil count ≥ 2% was 300 cells/µL (area under the ROC curve [AUC] 0.614, P = 0.001, 39% sensitivity, 83.8% specificity). When the eosinophilic COPD exacerbation was based on blood eosinophil count ≥ 300 cells/µL, the best cut-off value of blood eosinophil count in stable status for the prediction of eosinophilic COPD exacerbation was also 300 cells/uL (AUC 0.634, P = 0.046, 45.8% sensitivity, 80.9% specificity). CONCLUSIONS: We demonstrated association between blood eosinophil counts at stable COPD and those with AECOPD. The thresholds of blood counts at stable COPD to predict eosinophilic exacerbations was 300 cells/µL. Further and prospective studies in other populations should validate our results.

Comparison of the clinical characteristics and treatment outcomes of patients requiring hospital admission to treat eosinophilic and neutrophilic exacerbations of COPD.

PURPOSE: We compared the clinical characteristics and treatment outcomes of patients with eosinophilic and neutrophilic COPD exacerbations requiring hospital admission. PATIENTS AND METHODS: This was a retrospective multicenter study performed between January 2010 and December 2014. In all, 1,688 COPD patients admitted via the outpatient clinics or emergency departments of six university hospitals were enrolled. The patients were grouped by complete blood counts: eosinophilic group, >2% peripheral blood eosinophils, and neutrophilic group, >65% peripheral blood neutrophils or >11,000 leukocytes/mL. The patients with radiographic evidence of pneumonia at the time of admission, those with lung cancer, those admitted for treatment of other medical problems, and those who chronically used steroids were excluded. RESULTS: A total of 605 patients hospitalized with COPD exacerbations (177 eosinophilic and 380 neutrophilic) were included. Pulmonary functions, including the forced expiratory volume in 1 second and forced vital capacity, were better in patients with eosinophilic exacerbations. Treatment outcomes, including the rate of admission to the intensive care unit and mortality, were poorer in patients with neutrophilic exacerbations (4.5% vs 12.4%, P=0.004; 1.1% vs 4.5%, P=0.043, respectively). Congestive heart failure (odds ratio [OR] =3.40, 95% confidence interval [CI]: 1.28-9.01) and neutrophilic exacerbation (OR = 2.81, 95% CI: 1.21-6.52) were independent risk factors for intensive care unit admission. CONCLUSION: COPD patients with neutrophilic exacerbations experienced worse clinical outcomes than did those with eosinophilic exacerbations. The peripheral blood eosinophil count may be a useful predictor of clinical progress during hospitalization of COPD patients with acute exacerbations.

Extensive Bilateral Lemierre Syndrome due to Methicillin-Resistant Staphylococcus epidermidis in a Patient with Lung Adenocarcinoma.

Lemierre syndrome (LS) is a septic thrombophlebitis of the internal jugular vein (IJV) following an oropharyngeal infection. LS is commonly caused by normal anaerobic flora and treated with appropriate antibiotics and anticoagulation therapy. Although the incidence of disease is very rare, 15% cases of LS are fatal even in the antibiotic era because of disseminated septic thromboemboli. We reported a case of extensive bilateral LS due to methicillin-resistant Staphylococcus epidermidis in a 63-year-old female with lung adenocarcinoma. Initial examination revealed a retropharyngeal abscess; hence, intravenous ceftriaxone and steroid were initiated empirically. However, pulmonary thromboembolism developed and methicillin-resistant S. epidermidis was identified in the bacterial culture. Despite intensive antibiotic and anticoagulation therapies, extensive septic thrombophlebitis involving the bilateral IJV and superior vena cava developed. Adjunctive catheter-directed thrombolysis and superior vena cava stenting were performed and the patient received antibiotic therapy for an additional 4 weeks, resulting in complete recovery.

Expression of insulin-like growth factor 1 receptor (IGF-1R) predicts poor responses to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in non-small cell lung cancer patients harboring activating EGFR mutations.

OBJECTIVES: Expression of insulin-like growth factor 1 receptor (IGF-1R) in non-small cell lung cancer (NSCLC) is associated with poor prognosis. The IGF-1R pathway activates downstream targets that bypass dependency in signals from the epidermal growth factor receptor (EGFR), which mediates resistance to EGFR tyrosine kinase inhibitors (TKIs). The aim of the present study was to determine the predictive role of IGF-1R expression in the response to EGFR-TKIs of NSCLC patients harboring activating EGFR mutations. MATERIALS AND METHODS: We retrospectively studied 62 NSCLC patients who had activating EGFR mutations and received TKIs. Protein expression of IGF-1R, vascular endothelial growth factor (VEGF), and human epidermal growth factor receptor 2 (HER2) were measured by immunohistochemical staining. Univariate and multivariate analyses were performed to identify predictive factors associated with the responses to EGFR-TKIs. The relationship of progression-free survival (PFS) with IGF-1R expression and the presence of diabetes mellitus (DM) were examined. RESULTS: Of 62 EGFR mutation positive patients, 26 expressed IGF-1R, and 13 had DM. In the multivariate analysis, young age, squamous cell carcinoma, and IGF-1R expression were independently associated with a shorter PFS after treatment with EGFR-TKIs. Patients expressing IGF-1R showed a significantly shorter PFS in response to EGFR-TKIs compared with those lacking IGF-1R expression (9.1 vs. 20.1 months, p=0.005). The 13 patients with DM were more likely to express IGF-1R (p=0.001) and had shorter PFS times when treated with first-line EGFR-TKIs (7.6 vs. 18.6 months, p=0.005), compared with those without DM. CONCLUSION: IGF-1R expression was a negative predictive factor for a response to EGFR-TKIs in NSCLC patients harboring activating EGFR mutations. Moreover, patients with DM highly expressed IGF-1R in tumor tissues, which was associated with a poor response to first-line TKI therapy. Further studies aimed at overcoming EGFR-TKI resistance will need to also address IGF-1R pathways.

Rapid and sensitive detection of lower respiratory tract infections by stuffer-free multiplex ligation-dependent probe amplification.

Lower respiratory tract infection is one of the most common infectious diseases. However, conventional methods for detecting infectious pathogens are time-consuming, and generally have a limited impact on early therapeutic decisions. We previously reported a rapid and sensitive method for detecting such pathogens using stuffer-free multiplex ligation-dependent probe amplification coupled with high-resolution CE-SSCP. In this study, we report an application of this method to the detection of respiratory pathogens. As originally configured, this method was capable of simultaneously detecting seven bacterial species responsible for lower respiratory tract infections, but its detection limit and assay time were insufficient to provide useful information for early therapeutic decisions. To improve sensitivity and shorten assay time, we added a target-specific preamplification step, improving the detection limit from 50 pg of genomic DNA to 500 fg. We further decreased time requirements by optimizing the hybridization step, enabling the entire assay to be completed within 7 h while maintaining the same detection limit. Taken together, these improvements enable the rapid detection of infectious doses of pathogens (i.e. a few dozen cells), establishing the strong potential of the refined method, particularly for aiding early treatment decisions.

A multicenter phase II study of belotecan, a new camptothecin analogue, in elderly patients with previously untreated, extensive-stage small cell lung cancer.

PURPOSE: Belotecan is a new camptothecin analogue and a potent topoisomerase I inhibitor. The aim of this phase II study was to investigate the efficacy and toxicity of belotecan in previously untreated elderly patients with small cell lung cancer (SCLC). METHODS: A total of 26 patients, aged ≥65 years, with previously untreated, extensive-stage SCLC were enrolled in the study. Belotecan was administered by daily intravenous infusion at 0.5 mg/m(2)/day for 5 consecutive days every 3 weeks. RESULTS: The overall response rate and disease control rate of chemotherapy on an intention-to-treat basis were 35 and 54 %, respectively. The median overall survival was 6.4 months, and the median time to progression was 2.8 months. The most common toxicity was hematologic. Grade 3 or 4 neutropenia occurred in 80.8 % of patients, and grade 3 or 4 thrombocytopenia in 15.3 %. Non-hematologic toxic effects of grade 3 or 4 were uncommon. CONCLUSION: Belotecan had modest efficacy and well-tolerated toxicity in previously untreated, elderly SCLC patients. Single belotecan could be a promising treatment option, considering its lower toxicity in elderly patients who are unsuitable candidates for platinum plus etoposide chemotherapy.

Thrombin induces epithelial-mesenchymal transition via PAR-1, PKC, and ERK1/2 pathways in A549 cells.

Thrombin activates protease-activated receptor (PAR)-1 and induces a myofibroblast phenotype in normal lung fibroblasts. The origins of myofibroblasts are resident fibroblasts, fibrocytes, and epithelial-mesenchymal transition (EMT). We investigated the effects of thrombin, an important mediator of interstitial lung fibrosis, on EMT in A549 human alveolar epithelial cells. We show that thrombin induced EMT and collagen I secretion through the activation of PAR-1, and PKC and ERK1/2 phosphorylation in A549 cells. These effects were largely prevented by a specific PAR-1 antagonist, short interfering RNA (siRNA) directed against PAR-1, or specific PKCα/ß, δ, and ε inhibitors. These data indicated that interaction with thrombin and alveolar epithelial cells might directly contribute to the pathogenesis of pulmonary fibrosis through EMT. Targeting PAR-1 on the pulmonary epithelium or specific inhibitors to PKCα/ß, δ, and ε might stop the fibrotic processes in human idiopathic pulmonary fibrosis by preventing thrombin-induced EMT.

Effect of tiotropium bromide on airway remodeling in a chronic asthma model.

BACKGROUND: Recent evidence suggests that acetylcholine acting through muscarinic receptors may play an inhibitory role in the mechanisms that drive the structural changes in the airways called airway remodeling. The novel anticholinergic drug tiotropium bromide, which selectively antagonizes muscarinic receptors, especially the M3 subtype, and is long acting, could be beneficial in attenuating airway remodeling in chronic asthma. OBJECTIVE: To investigate the effect of tiotropium bromide on parameters of airway remodeling, including smooth muscle hypertrophy and peribronchial thickening, in a mouse model of chronic asthma. METHODS: To develop the murine models of acute and chronic asthma, BALB/c mice were sensitized and challenged to ovalbumin for 1 and 3 months, respectively. The effect of tiotropium bromide (0.1mM in 50 µL of phosphate-buffered saline) on pulmonary inflammation and remodeling was evaluated. The expression of muscarinic receptors M2 and M3 was analyzed. RESULTS: In the chronic asthma model, the tiotropium-treated group significantly decreased smooth muscle thickening and peribronchial collagen deposition. As for pulmonary inflammation, the chronic asthma model had a reduction of inflammatory cells and T(H)2 cytokines by tiotropium bromide, but the effects in the asthma acute model were reversed. In the chronic asthma model, expression of the M3 receptor was inhibited and that of the M2 receptor was elevated by the administration of tiotropium bromide. CONCLUSION: This study suggests that tiotropium bromide might have an inhibitory effect on airway remodeling in a murine model of chronic asthma. Differential effects on muscarinic receptor subtypes may explain why tiotropium bromide has different effects on acute and chronic asthma.

Inhibitory effect of receptor for advanced glycation end products (RAGE) on the TGF-ß-induced alveolar epithelial to mesenchymal transition.

Idiopathic pulmonary fibrosis (IPF) is a lethal parenchymal lung disease characterized by myofibroblast proliferation. Alveolar epithelial cells (AECs) are thought to produce myofibroblasts through the epithelial to mesenchymal transition (EMT). Receptor for advanced glycation end products (RAGE) is a member of the immunoglobulin superfamily of cell surface receptors whose activation is associated with renal fibrosis during diabetes and liver fibrosis. RAGE is expressed at low basal levels in most adult tissues except the lung. In this study, we evaluated the interaction of ligand advanced glycation end products (AGE) with RAGE during the epithelial to myofibroblast transition in rat AECs. Our results indicate that AGE inhibited the TGF-ß-dependent alveolar EMT by increasing Smad7 expression, and that the effect was abolished by RAGE siRNA treatment. Thus, the induction of Smad7 by the AGE-RAGE interaction limits the development of pulmonary fibrosis by inhibiting TGF-ß-dependent signaling in AECs.

Effect of nilotinib on bleomycin-induced acute lung injury and pulmonary fibrosis in mice.

BACKGROUND: The tyrosine kinase inhibitor imatinib mesylate was developed as an inhibitor of the kinase activity of BCR-ABL. However, imatinib also has potent inhibitory activity against the platelet-derived growth factor receptor (PDGFR). Nilotinib is approved for treating patients with chronic myeloid leukemia showing resistance or intolerance to imatinib. Like imatinib, nilotinib selectively inhibits the tyrosine kinase activity of PDGFR. OBJECTIVES: We examined the effect of imatinib and nilotinib on acute lung injury and pulmonary fibrosis in a mouse model. METHODS: Mice were treated by intratracheal instillation of bleomycin. Imatinib or nilotinib were administered by oral gavage. To study the early inflammatory and late fibrotic phases of lung injury, mice were sacrificed on days 3, 7, 14 and 21 after bleomycin instillation. RESULTS: Histopathology showed that imatinib and nilotinib attenuated the extent of lung injury and fibrosis. The numbers of inflammatory cells and levels of IL-6, IL-1ß and tumor necrosis factor-α were decreased in the imatinib and nilotinib groups on days 3 and 7. Imatinib and nilotinib therapy significantly reduced the levels of hydroxyproline on days 14 and 21, which was accompanied by decreased expression levels of transforming growth factor (TGF)-ß1 and PDGFR-ß. Imatinib and nilotinib also significantly reduced the expression levels of the genes for TGF-ß1 and platelet-derived growth factor (PDGF). Imatinib and nilotinib treatment also significantly inhibited the PDGF-induced proliferation of lung fibroblasts in vitro. When imatinib or nilotinib was given 7 days after the instillation of bleomycin, only nilotinib attenuated pulmonary fibrosis. CONCLUSIONS: Imatinib and nilotinib attenuated bleomycin-induced acute lung injury and pulmonary fibrosis in mice. In a therapeutic model, nilotinib showed more potent antifibrotic effects than imatinib.

Effect of pravastatin on bleomycin-induced acute lung injury and pulmonary fibrosis.

1. Pravastatin is best known for its antilipidemic action. Recent studies have shown that statins have immunomodulatory and anti-inflammatory effects. The present study aimed to determine whether or not pravastatin can attenuate acute lung injury and fibrosis in a mouse model. 2. Bleomycin was given to C57BL6 mice through intratracheal instillation. Pravastatin was given through intraperitoneal injection. To study the effect of pravastatin on the early inflammatory phase and the late fibrotic phase, mice were killed on days 3, 7, 14 and 21. 3. Pravastatin attenuated the histopathological change of bleomycin-induced lung injury and fibrosis. The accumulation of neutrophils and increased production of tumor necrosis factor-α in bronchoalveolar lavage fluid were inhibited in the early inflammatory phase. Pravastatin effectively inhibited the increase of lung hydroxyproline content induced by bleomycin. Furthermore, pravastatin reduced the increased expression of transforming growth factor (TGF)-ß1, connective tissue growth factor (CTGF), RhoA and cyclin D1. The increased levels of TGF-ß1 and CTGF mRNA expression were also significantly inhibited by pravastatin. 4. Pravastatin effectively attenuated bleomycin-induced lung injury and pulmonary fibrosis in mice. Our results provide evidence for the therapeutic potential of pravastatin in the treatment of acute lung injury and pulmonary fibrosis.

Inhibitory effect of CXC chemokine receptor 4 antagonist AMD3100 on bleomycin induced murine pulmonary fibrosis.

CXC chemokine receptor 4 (CXCR4), which binds the stromal cell-derived factor-1 (SDF-1), has been shown to play a critical role in mobilizing the bone marrow (BM)-derived stem cells and inflammatory cells. We studied the effects of AMD3100, CXCR4 antagonist, on a murine bleomycin-induced pulmonary fibrosis model. Treatment of mice with AMD3100 in bleomycin-treated mice resulted in the decrease of SDF-1 in bronchoalveolar lavage (BAL) fluids at an early stage and was followed by the decrease of fibrocytes in the lung. AMD3100 treatment decreased the SDF-1 mRNA expression, fibrocyte numbers in the lung at an early stage (day 3) and CXCR4 expression at the later stage (day 7 and 21) after bleomycin injury. The collagen content and pulmonary fibrosis were significantly attenuated by AMD3100 treatment in later stage of bleomycin injury. AMD3100 treatment also decreased the murine mesenchymal and hematopoietic stem cell chemotaxis when either in the stimulation with bleomycin treated lung lysates or SDF-1 in vitro. In BM stem cell experiments, the phosphorylation of p38 MAPK which was induced by SDF-1 was significantly blocked by addition of AMD3100. Our data suggest that AMD3100 might be effective in preventing the pulmonary fibrosis by inhibiting the fibrocyte mobilization to the injured lung via blocking the SDF-1/CXCR4 axis.

Effects of elastase inhibitor on the epithelial cell apoptosis in bleomycin-induced pulmonary fibrosis.

Alveolar epithelial cell injury and apoptosis is consistent findings in human idiopathic pulmonary fibrosis (IPF). Epithelial cell apoptosis is known to be induced by leukocyte elastase in vitro. The authors hypothesized that synthetic neutrophil elastase inhibitor, sivelestat (ONO-5046), can inhibit the bleomycin-induced pulmonary fibrosis in rats by blocking the apoptotic pathways in epithelial cells. Adult rats were injected with intratracheal bleomycin. Sivelestat was given for 13 days intraperitoneally after bleomycin treatments. Similar experiments were carried out in which A549 cells, a human alveolar type II epithelial cell line, were treated with bleomycin or neutrophil elastase. In rats, sivelestat decreased neutrophil counts and the cytokine-induced neutrophil chemoattractant (CINC)-1 in the bronchoalveolar lavage (BAL) fluid of bleomycin-treated rats. Sivelestat also decreased the bleomycin-induced lung inflammatory cell apoptosis by decreasing caspase-3 and -9 activities. In A549 cells, sivelestat decreased the elastase-induced epithelial cell apoptosis but not the bleomycin-induced epithelial cell apoptosis. Similarly, sivelestat inhibited the elastase-induced cell death but not the bleomycin-induced cell death in MTT assays. Sivelestat also inhibited the elastase-induced caspase-3 and -9 activities and cytochrome c release from the mitochondria but did not inhibit the bleomycin-induced caspase activities in A549 cells. In conclusion, bleomycin caused the lung inflammatory cell apoptosis through the caspase-9 and -3 pathways in rats. Sivelestat inhibited pulmonary fibrosis by blocking these mitochondria-mediated apoptotic pathways in bleomycin-treated rats and in elastase-treated A549 cells. These findings suggest that sivelestat can suppress the bleomycin-induced pulmonary fibrosis by blocking neutrophil chemotaxis and by inhibiting the neutrophil elastase-induced lung cell apoptosis in rats.

Risk factors for acute respiratory distress syndrome during neutropenia recovery in patients with hematologic malignancies.

INTRODUCTION: Neutropenia recovery may be associated with deterioration in oxygenation and exacerbation of pre-existing pulmonary disease. However, risk factors for acute respiratory distress syndrome (ARDS) during neutropenia recovery in patients with hematologic malignancies have not been studied. METHODS: We studied critically ill patients with hematologic malignancies with the dual objectives of describing patients with ARDS during neutropenia recovery and identifying risk factors for ARDS during neutropenia recovery. A cohort of consecutive neutropenic patients with hematologic malignancies who were admitted to the intensive care unit (ICU) was studied. During a 6-year period, 71 patients recovered from neutropenia, of whom 38 (53.5%) developed ARDS during recovery. RESULTS: Compared with non-ARDS patients, patients who experienced ARDS during neutropenia recovery were more likely to have pneumonia, be admitted to the ICU for respiratory failure, and receive mechanical ventilator therapy. The in-ICU mortality was significantly different between the two groups (86.8% versus 51.5%, respectively, for patients who developed ARDS during neutropenia recovery versus those who did not during neutropenia recovery). In multivariate analysis, only occurrence of pneumonia during the neutropenic episode was associated with a marked increase in the risk of ARDS (odds ratio, 4.76). CONCLUSIONS: Patients with hematologic malignancies complicated by pneumonia during neutropenia are at increased risk for ARDS during neutropenia recovery.

Nitric oxide induces MUC5AC mucin in respiratory epithelial cells through PKC and ERK dependent pathways.

BACKGROUND: Nitric oxide (NO) is generally increased during inflammatory airway diseases. This increased NO stimulates the secretion of mucin from the goblet cell and submucosal glands but the mechanism is still unknown precisely. In this study, we investigated potential signaling pathways involving protein kinase C (PKC) and mitogen-activated protein kinase (MAPK) in the NO-induced MUC5AC mucin gene and protein expression in A549 cells. METHODS: Nitric oxide was donated to the A549 cells by NOR-1. MUC5AC mucin levels were assayed by enzyme-linked immunosorbent assay (ELISA). MUC5AC promoter activity was determined by measuring luciferase activity after the lysing the transfected cells. Activation of PKC isoforms were measured by assessing the distribution of the enzyme between cytosolic and membrane fractions using immunoblotting. Immunoblotting experiments using a monoclonal antibody specific to PKC isoforms were performed in the cytosol and membrane fractions from A549 cells. Western blot analysis for pERK and p38 were performed using the corresponding antibodies from the cell lysates after donating NO to the A549 cells by NOR-1. RESULTS: The transcriptional activity of MUC5AC promoter was maximal at the concentration of 0.1 mM NOR-1 for 1 hour incubation in transfected A549 cells. (+/-)-(E)-methyl-2-((E)-hydroxyimino)-5-nitro-6-methoxy-3-hexenamide (NOR-1) markedly displaced the protein kinase C (PKC)alpha and PKCdelta from the cytosol to the membrane. Furthermore, the PKC-alpha,betainhibitors, GO6976 (10 nM) and PKCdelta inhibitors, rottlerin (4 muM) inhibited the NOR-1 induced migration of PKCalpha and PKCdelta respectively. NOR-1 also markedly increased the MUC5AC promoter activity and mRNA expression, mucin synthesis and ERK1/2 phosphorylation. The PKC inhibitors also inhibited the NOR-1 induced MUC5AC mRNA and MUC5AC protein synthesis by inhibiting the activation of PKCalpha and PKCdelta with ERK1/2 pathways. CONCLUSION: Exogenous NO induced the MUC5AC mucin gene and protein through the PKCalpha and PKCdelta-ERK pathways in A549 cells. Inhibition of PKC attenuated NO-mediated MUC5AC mucin synthesis. In view of this findings, PKC inhibitors might be useful in the treatment of bronchial asthma and chronic bronchitis patients where NO and mucus are increased in the bronchial airways.

Neutrophil elastase causes MUC5AC mucin synthesis via EGF receptor, ERK and NF-kB pathways in A549 cells.

BACKGROUND: Neutrophil elastase (NE) was found to increase the respiratory mucin gene, MUC5AC, although the molecular mechanisms of this process remain unknown. We attempted to determine the signal transduction pathway through which NE induces MUC5AC gene expression in bronchial epithelial cells. METHODS: A fragment of 1.3 Kb MUC5AC promoter which had been cloned into the pGL3-Basic luciferase vector was transfected to the A549 cells. By measuring the luciferase activity, we were able to evaluate the MUC5AC promoter activity in A549 cells. The involvement of mitogen-activated protein kinases (MAPK) was confirmed by Western blotting. To confirm the involvement of nuclear factorkappaB (NF-kB), we used site-directed mutagenesis and electrophoretic mobility shift assay (EMSA) autoradiogram. The MUC5AC mRNA expression was confirmed by RT-PCR. RESULTS: NE increased the transcriptional activity of the MUC5AC promoter in A549 cells. The increased transcriptional activity of the MUC5AC promoter by NE was found to be associated with increased NF-kB activity. Site-directed mutagenesis showed that the transfection of the mutated NF-kB binding sites from the PGL3-MUC5AC-3752 promoter luciferase reporter plasmid decreased the luciferase activity after NE stimulation. Among the MAPKs, only extracellular signal-regulated kinases (ERK) were involved in this NE-induced MUC5AC mucin expression. RT-PCR also showed that NE increased MUC5AC mRNA. An EMSA autoradiogram revealed that NE induced NF-kB:DNA binding. CONCLUSIONS: These results indicate that human NE induces MUC5AC mucin through the epidermal growth factor receptor (EGF-R), ERK, and NF-kB pathways in A549 cells.