Pseudomonas aeruginosa induces MUC5AC production via epidermal growth factor receptor.

Hypersecretory disease associated with Pseudomonas aeruginosa (PA) infections is characterised by increased goblet cells and increased mucin production. Recently, an epidermal growth factor receptor (EGFR) signalling cascade was shown to be a common pathway through which many stimuli induce mucin MUC5AC expression in airways by differentiation to a goblet cell phenotype. This study looked at whether PA products induce EGFR expression and activation and thus result in mucin MUC5AC production. Human airway epithelial (NCI-H292) cells were stimulated with PA culture supernatant (Sup). MUC5AC protein production, MUC5AC and EGFR messenger ribonucleic acid (mRNA) expression, and phosphorylated EGFR and phosphorylated p44/42 mitogen-activated protein kinase (MAPK) were all examined using enzyme-linked immunosorbent assay, by in situ hybridisation and by immunoblotting. PA Sup induced MUC5AC mRNA and subsequent protein expression, EGFR and p44/42 MAPK phosphorylation and EGFR mRNA expression. Induction of MUC5AC mRNA and protein expression and EGFR and p44/42 MAPK phosphorylation were inhibited completely by pretreatment with a selective EGFR tyrosine kinase inhibitor. Pretreatment with a selective inhibitor of MAPK kinase prevented MUC5AC production and p44/42 MAPK phosphorylation but not EGFR phosphorylation. The authors conclude that PA products induce mucin MUC5AC production in human airway epithelial cells via the expression and activation of epidermal growth factor receptor.     

白细胞介素-13对人支气管上皮细胞SPDEF表达的影响及SPDEF在哮喘气道黏液高分泌中的作用

目的探讨白细胞介素(IL)-13对人支气管上皮细胞SPDEF表达的影响及SPDEF在哮喘气道黏液高分泌中的作用。方法将人原代支气管上皮细胞(NHBE细胞)分为对照组、IL-13组及IL-13+SPDEF siRNA组。培养28天后,收集NHBE细胞并提取总RNA,采用实时荧光定量聚合酶链反应检测NHBE细胞SPDEF、粘蛋白MUC5AC及MUC5B mRNA的表达水平,流式细胞术检测MUC5AC阳性细胞数量和免疫荧光强度,免疫荧光染色检测粘蛋白MUC5AC和MUC5B的表达水平。结果IL-13组NHBE细胞SPDEF和MUC5AC mRNA的表达水平、MUC5AC阳性细胞数量和免疫荧光强度均明显高于对照组(P<0.001),而MUC5B mRNA的表达水平明显低于对照组(P<0.05);IL-13+SPDEF siRNA组NHBE细胞SPDEF和MUC5AC mRNA的表达水平、MUC5AC阳性细胞数量和免疫荧光强度均明显低于IL-13组(P<0.001);IL-13+SPDEF siRNA组MUC5B mRNA的表达水平明显低于对照组(P<0.05)。IL-13组NHBE细胞MUC5AC的表达水平明显高于对照组和IL-13+SPDEF siRNA组,而MUC5B的表达水平低于对照组。结论IL-13可能通过诱导人支气管上皮细胞SPDEF上调,促进气道粘蛋白MUC5AC的高表达,引起哮喘气道黏液高分泌。     

Melatonin inhibits MUC5AC production via suppression of MAPK signaling in human airway epithelial cells

Mucus acts as a primary defense system in the airway against various stimuli. However, excess mucus production causes a reduction in lung function via limitation of the airflow in the airway of patients suffering from asthma or chronic obstructive pulmonary disease (COPD). In this study, we evaluated the effects of melatonin on the production of MUC5AC, a major constituent of the mucin that is secreted from the airway, using epidermal growth factor (EGF)‐stimulated NCI‐H292 cells, a human mucoepidermoid carcinoma cell line, and an ovalbumin (OVA)‐induced asthma murine model. Melatonin treatment significantly reduced the mRNA and protein levels of MUC5AC and reduced interleukin (IL)‐6 production in EGF‐stimulated H292 cells. Melatonin markedly decreased the phosphorylation of MAPKs, including ERK1/2, JNK, and p‐38, induced by EGF stimulation. These findings were consistent with the results using MAPK inhibitors. Particularly, co‐treatment with melatonin and a MAPK inhibitor more effectively suppressed MAPK phosphorylation than treatment with a MAPK inhibitor alone, which resulted in a reduction in MUC5AC expression. In the asthma murine model, melatonin‐treated mice exhibited a marked reduction in MUC5AC expression in the airway compared with the OVA‐induced mice. These reductions were accompanied by reductions in proinflammatory cytokine production and inflammatory cell infiltration. Collectively, these findings indicate that melatonin effectively inhibits MUC5AC expression. These effects may be closely associated with the inhibition of MAPK phosphorylation. Furthermore, our study suggests that melatonin could represent a potential therapeutic for chronic airway diseases, such as asthma and COPD.     

白细胞介素13对小鼠支气管哮喘模型肺组织钙激活的氯通道gob-5和黏蛋白基因MUC5AC表达的作用

目的　研究白细胞介素 13(IL 13)对小鼠支气管哮喘 (简称哮喘 )模型肺组织“钙激活的氯通道”成员gob 5和黏蛋白基因MUC5AC表达的影响 ,了解其在哮喘发病中的作用。方法　 4 5只雄性BALB/c小鼠按随机数字表法分为对照组、哮喘组和IL 13组 ,每组 15只。用逆转录 聚合酶链反应(RT PCR)测定方法和免疫组化法分别检测gob 5mRNA、MUC5ACmRNA和MUC5AC蛋白在肺组织的表达。结果　对照组小鼠肺组织中gob 5mRNA表达为 0 0 0 0± 0 0 0 0 ,哮喘组为 1 136± 0 0 0 7,两组比较差异有统计学意义 (P <0 0 1) ;IL 13组小鼠肺组织中gob 5mRNA为 1 2 4 6± 0 0 0 8,哮喘组为 1 136± 0 0 0 7,两组比较差异有统计学意义 (P <0 0 1) ;对照组小鼠MUC5ACmRNA(0 0 70± 0 0 0 4 )和蛋白 (2只小鼠阳性 )表达与哮喘组 (分别为 0 16 1± 0 0 11和 7只小鼠阳性 )比较 ,差异均有统计学意义 (P分别 <0 0 1、0 0 5 ) ;经IL 13处理后的哮喘小鼠肺组织中MUC5ACmRNA (0 2 5 0± 0 0 14 )和蛋白 (13只小鼠阳性 )的表达与对照组 (分别为 0 0 70±0 0 0 4、2只小鼠阳性 )、哮喘组 (分别为 0 16 1± 0 0 11、7只小鼠阳性 )比较 ,差异均有统计学意义 (P均 <0 0 5 ) ;哮喘组和IL 13组小鼠肺组织中gob 5mRNA表达与MUC5ACm     

Tumor necrosis factor alpha-converting enzyme mediates MUC5AC mucin expression in cultured human airway epithelial cells

Ectodomain shedding of epidermal growth factor receptor (EGFR) ligands [e.g., transforming growth factor type alpha (TGF-alpha)] and EGFR phosphorylation are implicated in mucin production in airway epithelial cells. Tumor necrosis factor alpha-converting enzyme (TACE) is reported to cleave precursor of TGF-alpha, with release of soluble mature TGF-alpha in various epithelial tissues. We hypothesized that TACE increases the shedding of TGF-alpha, resulting in EGFR phosphorylation and inducing mucin production in human airway epithelial (NCI-H292) cells. To examine this hypothesis, we stimulated NCI-H292 cells with phorbol 12-myristate 13-acetate (PMA, an activator of TACE) and pathophysiologic stimuli [lipopolysaccharide (LPS) and supernatant from the Gram-negative bacterium Pseudomonas aeruginosa (PA sup)]. PMA, PA sup, and LPS increased MUC5AC gene expression and mucin protein production, effects that were prevented by pretreatment with AG1478, a selective inhibitor of EGFR phosphorylation and by preincubation with an EGFR-neutralizing Ab or with a TGF-alpha-neutralizing Ab, implicating ligand (TGF-alpha)-dependent EGFR phosphorylation in mucin production. These stimuli induced release of soluble TGF-alpha, EGFR phosphorylation, and MUC5AC expression, which were blocked by the metalloprotease inhibitors tumor necrosis factor-alpha protease inhibitor-1 and tissue inhibitor of metalloprotease-3. We specifically knocked down the expression of metalloprotease TACE by using small interfering RNA for TACE. Knockdown of TACE inhibited PMA-, PA sup-, and LPS-induced TGF-alpha shedding, EGFR phosphorylation, and mucin production. From these results, we conclude that TACE plays a critical role in mucin production by airway epithelial cells by means of a TACE ligand-EGFR cascade in response to various stimuli.     

Regulation of Viral Infection-induced Airway Remodeling Cytokine Production by the TLR3-EGFR Signaling Pathway in Human Bronchial Epithelial Cells

Toll-like receptor 3 (TLR3) is involved in the virus-induced pulmonary inflammatory response, but its role in airway remodeling after viral infection is unclear. We explored the role of TLR3 in poly(I:C)-induced inflammatory cytokines and mucin 5AC (MUC5AC) production in human bronchial epithelial cells by Western blotting, RT-PCR and ELISA. The expression of TLR3, MUC5AC, Matrixmetalloproteinase (MMP9), Transforming growth factor (TGF-β1) and Vascular endothelial growth factor (VEGF) in human bronchial epithelial cells increased in a dose-dependent manner after exposure to poly(I:C), and this effect was inhibited by treatment with TLR3 siRNA. The phosphorylation of epithelial growth factor receptor (EGFR)/ERK/P38 Mitogen-activated protein kinases (MAPK) proteins increased after poly(I:C) treatment, and inhibition of this signaling pathway decreased TLR3 expression and MUC5AC and TGF-β1 production in human bronchial epithelial cells. The TLR3-EGFR signaling pathway is involved in the production of airway remodeling cytokines after virus infection. Inhibiting EGFR and its signaling pathway may be a therapeutic strategy for modifying airway remodeling.     

Relationship of epidermal growth factor receptors to goblet cell production in human bronchi

To determine the relationship of epidermal growth factor receptor (EGFR) expression to mucin synthesis in human airways, we examined EGFR and MUC5AC expression at both gene and protein levels using in situ hybridization and immunohistochemical analysis in human bronchi. Bronchial mucosal biopsy specimens were obtained from 12 asthmatic subjects and 11 healthy subjects. In asthmatic airways, EGFR mRNA was expressed in the airway epithelium. EGFR immunoreactivity staining patterns varied among the asthmatic airways: staining was positive mainly in goblet cells, in basal cells, or in both. In contrast, healthy airways showed little expression of EGFR mRNA; EGFR immunoreactivity was observed mainly in goblet cells. In parallel to EGFR expression, MUC5AC mRNA expression was greater in asthmatic airways; mucous glycoconjugates that stained positively with Alcian blue/PAS were also increased in asthmatic airways. Ciliated cells were negative for EGFR and MUC5AC both in asthmatic and in healthy subjects at both mRNA and protein levels. There was a significant positive correlation between EGFR immunoreactivity and the area of MUC5AC-positive staining in both asthmatics and healthy subjects. These findings suggest a sequence of events by which EGFR activation is involved in mucin expression in asthmatic airway epithelium.     

表皮生长因子协同上调不分型流感嗜血杆菌诱导的MUC5AC表达及其信号通路

目的 探索表皮生长因子(EGF)协同上调不分型流感嗜血杆菌(NTHi)诱导MUC5AC黏液素基因表达的细胞分子机制.方法 荧光定量PCR及Luciferase分析EGF协同上调NTHi诱导的MUCSAC表达.Western印迹法检测EGF及NTHi对P38有丝分裂原活化蛋白激酶(P38MAPK)、细胞外信号调节激酶(ERK)、P21激活激酶(PAK)4磷酸化的协同作用.采用P38MAPK或EGF特异性抑制剂,共转染P38MAPK、ERK显性失活质粒及PAK4 siRNA,判断对EGF协同上调NTHi诱导MUC5AC表达的影响,并研究PAK4显性失活质粒对EGF及NTHi所致的P38MAPK及ERK协同激活的影响.结果 在HM3、HeLa和HMEEC-1细胞mRNA及转录水平上,EGF协同上调NTHi诱导的MUC5AC基因表达.EGF及NTHi对P38MAPK、ERK、PAK4磷酸化有协同作用;P38MAPK、ERK特异性抑制剂或共转染P38MAPK、ERK显性失活质粒、PAK4siRNA,可显著抑制EGF对NTHi诱导的MUC5AC表达的协同作用,PAK4显性失活质粒抑制EGF和NTHi诱导的P38MAPK和ERK磷酸化的协同作用.结论 EGF通过PAK4依赖的P38MAPK及ERK细胞信号通路协同上调NTHi诱导的MUCSAC黏液素基因表达.     

水通道蛋白敲除对支气管哮喘小鼠气道黏蛋白谱表达的影响

目的 水通道蛋白5(aquaporin 5,AQP5)敲除对支气管哮喘(简称哮喘)小鼠气道黏蛋白(MUC)谱表达的影响.方法 用卵白蛋白致敏和激发制备AQP5敲除鼠的哮喘高分泌模型.用苏木精-伊红染色观察气道及血管周围炎性细胞浸润.阿辛兰-过碘酸雪夫检测显示气道上皮细胞总黏液分泌,免疫组织化学检测气道上皮MUC5AC,MUC5B,MUC2的表达情况.结果 哮喘小鼠气道和血管周围可见大量中性粒细胞,淋巴细胞和嗜酸粒细胞浸润,气道上皮有大量的紫红色中性黏液分布,其中以AQP5敲除鼠总黏液分布更多.免疫组织化学显示小鼠哮喘高分泌模型中MUC谱主要为MUC5AC和MUC5B,未见MUC2分布.与野生型哮喘小鼠比较,MUC5AC、MUC5B在AQP5敲除鼠中表达更丰富.结论 AQP5基因缺失可能使小鼠气道对过敏原的应激性提高,从而促进黏液高分泌.     

A role for 12R-lipoxygenase in MUC5AC expression by respiratory epithelial cells

Eicosanoids are metabolites of arachidonic acid produced by cyclooxygenases (COXs) or lipoxygenases (LOXs). They mediate inflammation and mucus secretion in chronic pulmonary inflammatory diseases. The gel-forming mucin MUC5AC is over-expressed in the airways of patients with these diseases. MUC5AC expression is mediated by an extracellular signal-regulated kinase (ERK)/Sp1 dependent mechanism. Our aim was to study the role of eicosanoids and their signalling pathways in MUC5AC expression. Inhibitors of 12-LOX, but not those of COX, 5-LOX or 15-LOX, reduce MUC5AC expression induced by phorbol myristate acetate (PMA) in the bronchial epithelial cell line NCI-H292. These inhibitors also abrogate the production of whole mucus by cell monolayers. Two forms of 12-LOX (R and S) exist in mammals. Using siRNAs we show that 12R-LOX but not 12S-LOX is involved in MUC5AC expression induced by PMA, lipopolysaccharide or transforming growth factor-α. 12R-LOX also participates in MUC2 and MUC5B expression, although to a lesser extent than for MUC5AC. Contrarily, 12R-LOX silencing does not modify interleukin-8 production. 12-LOX inhibitors reduce ERK activation and Sp1 translocation induced by PMA. Moreover, the 12R-LOX product 12(R)-hydroxyeicosatetraenoic acid, induces MUC5AC expression, ERK activation and Sp1 translocation. 12R-LOX is involved in MUC5AC expression. This occurs via ERK- and Sp1-signalling pathways.     

烟曲霉暴露对支气管哮喘大鼠气道黏蛋白MUC2表达的影响

目的研究烟曲霉暴露对支气管哮喘（简称哮喘）大鼠气道黏蛋白MUC2表达的影响。方法70只雄性Wistar大鼠随机数字表法分为7组（每组10只）：慢性哮喘（A）组、慢性哮喘＋烟曲霉孢子吸入1周（B）组、3周（C）组和5周（D）组、慢性哮喘＋生理盐水吸入（E）组、卵清白蛋白（0VA）致敏生理盐水激发（F）组和OVA致敏生理盐水激发＋烟曲霉孢子吸入（G）组。测定各组大鼠的基础气道阻力和气道阻力变化率,ELISA法测定支气管肺泡灌洗液（BALF）中IL-13水平,RT—PCR法检测肺组织MUC2mRNA水平,免疫组织化学染色测定气道上皮细胞MUC2表达强度。结果D组大鼠基础气道阻力为（1．06±0．28）cmH20·ml^-1·S^-1、气道阻力变化率为（85．69±5．68）％、BALF中IL-13为（197±34）mg／L、肺组织MUC2mRNA／β-actinmRNA为（3．0±0．6）、气道上皮细胞MUC2表达强度（A值）为（871±70）均高于A组[（o．52±0．13）cmH20·ml^-1·S^-1、（31．62±3．62）oA、（54±9）mg／L、（1．8±0．4）、（202±36）]、B组[（O．54土0．14）cmH20·ml^-1·S^-1、（35．90±2．62）％、（96土16）mg／L、（1．9±0．3）、（258±48）]、C组[（o．89±0．22）cmH20·ml^-1·S^-1、（60．91±4．26）％、（136±22）mg／L、（2．3±0．5）、（546土54）]和E组[（60．91±4．26）C1TIH20·ml^-1·S^-1、（31．64±3．47）％、（37±8）mg／L、（1．7±0．4）、（188±39）]（P〈O．01或P〈O．05）;A组高于F组[（0．33±0．08）cmH20·ml^-1·S^-1、（16．85±3．62）％、（23±6）mg／L、（O．5±0．2）、（87±18）]和G组[（O．34±0．12）cmH20·ml^-1·S^-1、（16．52±3．34）％、（25±6）mg／L、（O．5±0．1）、（88±15）]（P〈0．01或P〈0．05）;大鼠肺组织MUC2mRNA／β-actinmRNA和气道上皮细胞MUC2表达强度（A值）均与BAI,F中IL-13水平正相关（r=0．648,P〈0．05;r=0．676,P〈i0．05）,与气道阻力变化率正相关（r=0．644,P〈0．05;r=0．584,P〈0．05）。结论慢性烟曲霉暴露可上调哮喘大鼠气道黏蛋白MUC2基因表达,气道黏液分泌增多,黏稠度和黏滞度增加,导致气道反应性增高。     

LPS-induced mucin expression in human sinus mucosa can be attenuated by hCLCA inhibitors

BACKGROUND: hCLCA1 is a member of the calcium-activated chloride channel family and is associated with disease-inducible mucus expression. Niflumic acid (NFA) and a closely related chemical structure are reported inhibitors of calcium-activated chloride channels and endotoxin-inducible mucus expression in the mouse. Therefore, we tested the hypothesis that hCLCA1 may be involved in lipopolysaccharide (LPS) induced mucin up-regulation in human airways. We also investigated the effect of NFA and MSI-2216 on LPS-induced mucin up-regulation. MATERIALS AND METHODS: Explanted human airways and the muco-epidermoid cell line Calu-3 were stimulated with LPS. Different concentrations of NFA or MSI-2216 were added to LPS-stimulated airway mucosa and Calu-3 cells. Expression of hCLCA1 and MUC5AC mRNA and protein was quantified in human airways using real-time PCR and PAS staining. In addition, immunohistochemistry was performed for quantification of inflammatory cells (lymphocytes, monocytes, eosinophils, and neutrophils) in the submucosa of the airways. Expression of hCLCA1 protein in Calu-3 cells was analysed by FACS. RESULTS: LPS significantly induced hCLCA1 and MUC5AC mRNA and protein expression in human airway mucosa (P < 0.05). NFA and MSI-2216 significantly decreased LPS-induced mucus expression in explanted airway mucosa in a dose-dependent manner (P < 0.05). In Calu-3 cells, LPS significantly increased hCLCA1 surface expression whereas intracellular expression was significantly decreased (P < 0.05). In Calu-3 cells, NFA and MSI-2216 also significantly reduced MUC5AC mRNA expression (P < 0.05). CONCLUSIONS: These data suggest that hCLCA1 may play a role in LPS-induced mucin expression in human airway mucosa. Calcium-activated chloride channel inhibitors significantly decreased LPS-induced mucus expression both ex vivo and in vitro . Therefore, blocking of hCLCA1 may offer a therapeutic approach to reduce bacterial-induced mucus hypersecretion.     

不分型流感嗜血杆菌上调人类MUC5AC黏液素的基因表达

目的 探索不分型流感嗜血杆菌(NTHi)上调人类MUC5AC黏液素基因表达的细胞分子机制.方法 通过反转录套式-PCR及实时荧光定量PCR分析NTHi所诱导的MUC5AC mRNA的表达,免疫沉淀及Western印迹法检测NTHi对表皮生长因子受体(EGFR)及p38丝裂原活化蛋白激酶(p38MAPK)的激活,采用p38 MAPK或EGFR特异性抑制剂,共转染EGFR显性失活质粒,判断在转录水平对NTHi所诱导的MUC5AC表达的影响,并研究EGFR特异性抑制剂对NTHi所诱导p38MAPK激活的影响.结果 在人结肠上皮细胞株(HM3)细胞中,NTHi在mRNA及转录水平上调人类MUC5AC黏液素基因的表达,NTHi能使EGFR或p38MAPK磷酸化.p38MAPK、EGFR特异性抑制剂或共转染EGFR显性失活质粒,可显著抑制NTHi所诱导的MUC5AC的表达,EGFR特异性抑制剂对NTHi所诱导p38MAPK磷酸化有抑制作用.结论 不分型流感嗜血杆菌可通过EGFR-p38MAPK信号通路,上调人类MUC5AC黏液素基因表达.     

水通道蛋白敲除对支气管哮喘小鼠气道黏蛋白谱表达的影响

目的水通道蛋白5（aquaporin5,AQP5）敲除对支气管哮喘（简称哮喘）小鼠气道黏蛋白（MUC）谱表达的影响。方法用卵白蛋白致敏和激发制备AQP5敲除鼠的哮喘高分泌模型。用苏木精-伊红染色观察气道及血管周围炎性细胞浸润。阿辛兰-过碘酸雪夫检测显示气道上皮细胞总黏液分泌,免疫组织化学检测气道上皮MUC5AC,MUC5B,MUC2的表达情况。结果哮喘小鼠气道和血管周围可见大量中性粒细胞,淋巴细胞和嗜酸粒细胞浸润,气道上皮有大量的紫红色中性黏液分布,其中以AQP5敲除鼠总黏液分布更多。免疫组织化学显示小鼠哮喘高分泌模型中MUC谱主要为MUC5AC和MUC5B,未见MUC2分布。与野生型哮喘小鼠比较,MUC5AC、MUC5B在AQP5敲除鼠中表达更丰富。结论AQP5基因缺失可能使小鼠气道对过敏原的应激性提高,从而促进黏液高分泌。     

TIM-1对卵蛋白致敏小鼠肺组织黏蛋白SAC及T—bet表达的影响

目的研究T细胞免疫球蛋白-黏蛋白1（TcellIgandmucin-1,TIM-1）对支气管哮喘（简称哮喘）小鼠肺组织黏蛋白（mucin5AC,MUC5AC）及T—bet表达的影响,探讨TIM-1参与气道黏液高分泌的机制。方法卵蛋白（ovalbumin,0VA）腹腔注射致敏小鼠,随机分为正常对照组、哮喘组和哮喘＋TIM-1抗体处理组（TIM—1组）,每组10只。检测小鼠外周血单个核细胞（PBMCs）TIM-1＋细胞比例,实时RT—PCR检测小鼠肺组织MUC5ACmRNA及T-betmRNA表达变化。结果①哮喘组及TIM-1组小鼠外周血PBMCs中TIM-1＋细胞比例分别为（13．15％和7．42％）,均高于正常对照组（1．12％）（P〈O．01）,且TIM-1组低于哮喘组（P〈0．01）;②与对照组小鼠肺组织表达MUC5ACrnRNA（0．223±0．017）相比,哮喘组（1．121士0．082）及TIM-1组（O．771±0．040）表达明显增多（Pd0．01）,且TIM-1组小鼠肺组织表达MUC5ACmRNA较哮喘组降低（Pd0．01）;③哮喘组及TIM-1组小鼠肺组织表达rr-betrnRNA分别为（O．187±0．011）及（O．689±0．057）,较对照组降低（1．001±0．085）（P〈0．01）,而与哮喘组相比,TIM-1组表达有所增多（Pd0．01）;④TIM—1＋细胞比例与MUC5ACmRNA表达比例呈正相关（r1=0．918,P〈0．01）,而与T—bet1TIRNA表达呈负相关（r2=-0．958,P〈0．01）。结论抑制TIM-1表达可通过增强T-betmRNA表达,减少气道MUC5ACmRNA表达,调控气道黏液分泌。     

The inhibitory effects of rebamipide on cigarette smoke-induced airway mucin production

Cigarette smoke may be the main cause of chronic bronchitis. Exposure of cigarette smoke induces the recruitment of inflammatory cells in the airway epithelium, and release of the tumor necrosis factor alpha (TNFalpha) from airways. Previous reports have shown that cigarette smoke induces goblet cell metaplasia by activating an epidermal growth factor receptor (EGFR) cascade, and that this results in mucin production. Rebamipide (2-(4-chlorobenzoylamino)-3-[2(1H)-quinolinon-4-yl] propionic acid, OPC-12759) directly inhibits the production of superoxide (O2-) and inhibits proinflammatory cytokines (such as TNFalpha and IL-8). In the present study, we aimed to analyze the inhibitory effects of rebamipide on TNFalpha and EGFR activation after cigarette smoke treatment in vitro and in vivo. NCl-H292 cells and Sprague-Dawley rats were used for in vitro and in vivo studies. In vitro studies, cigarette smoke solution was found to increase TNFalpha secretion, and EGFR-specific tyrosine phosphorylation, and to elevate MUC5AC production. These effects were inhibited dose-dependently by pretreatment with rebamipide (MUC5AC protein levels were inhibited from 44% to 17%, P<0.05). In vivo studies, cigarette smoke was found to cause inflammatory cell recruitment and to increase the secretion of TNFalpha in bronchoalveolar lavage (BAL) fluids (from 198+/-78 to 2270+/-158 pg/ml, P<0.01). Moreover, the pretreatment of rats with rebamipide inhibited goblet cell metaplasia and TNFalpha secretion, dose-dependently (from 2270+/-158 to 1377+/-112 pg/ml, P<0.05). In conclusion, the exposure of airway epithelium to cigarette smoke-induced TNFalpha production, neutrophil recruitment, activated EGFR, and caused MUC5AC mucin synthesis. Moreover, rebamipide was found to prevent this cigarette smoke-induced TNFalpha release, and mucin production.