N-acetyl-L-cysteine inhibits bleomycin-induced interleukin-8 secretion by bronchial epithelial cells

OBJECTIVE: Bleomycin (BLM) has proven effective for the treatment of cancers, but the most serious dose-limiting side-effect is the development of pulmonary toxicity. Although the precise mechanism in the pathogenesis of BLM-induced lung injury has not been determined, oxygen radicals and neutrophils are indicated to play a key role in it. Interleukin-8 (IL-8) is thought to be an important mediator of the pathogenesis of acute lung injury. METHODOLOGY: The IL-8 production from bronchial epithelial cell line, BEAS-2B cells was measured by enzyme-linked immunosorbent assays for IL-8. RESULTS: The concentrations of IL-8 were reportedly elevated in BLM-induced lung injury, suggesting the involvement of IL-8 in the pathogenesis of BLM-induced lung injury. In the present study, we showed that BLM induced the expression of IL-8 protein and mRNA in BEAS-2B cells, and N-acetyl-L-cysteine (NAC) inhibited IL-8 expression. In addition, the structurally unrelated antioxidant, pyrrolidine dithiocarbamate (PDTC) also effectively inhibited BLM-induced IL-8 production. CONCLUSION: These results suggest that anti-oxidant-sensitive mechanism might be involved in the inhibition of IL-8 secretion by BLM-stimulated bronchial epithelial cells and that NAC might be useful for the treatment of BLM-induced lung injury.     

Effects by 8-bromo-cyclicAMP on basal and organic dust-induced release of interleukin-6 and interleukin-8 in A549 human airway epithelial cells

Inhalation of organic dust from a swine-confinement building leads to an intense inflammatory reaction with an increased number of inflammatory cells and mediators in the upper and lower respiratory tract of previously unexposed subjects. In vitro the dust induces cytokine release from epithelial cells and alveolar macrophages. It is known that intracellular cyclic AMP (cAMP) contributes to the regulation of inflammatory responses. We therefore investigated whether 8-Bromo-cAMP, a cell membrane-permeable cAMP analogue, would influence release of the cytokines interleukin-6 (IL-6) and IL-8 in a human airway epithelial cell line, A549, exposed to a suspension of the organic dust, and to a supernatant prepared by centrifugation (at low g-force) of a suspension of dust. The large particulate matter was thus sedimented, leaving bacteria, whole and cell wall constituents in the supernatant. Cytokine release was measured with enzyme-linked immunosorbent assay (ELISA). The cytokine release induced by a supernatant was 23% (IL-6) and 27% (IL-8) of the release induced by a dust suspension. 8-Bromo-cAMP (1 mM) doubled basal IL-6 release and IL-6 release induced by a dust supernatant (P<0.01), and increased IL-6 release induced by a dust suspension by 19% (P<0.05). 8-Bromo-cAMP did not affect basal IL-8 release, partially inhibited (28%) the release of IL-8 induced by a dust suspension (P<0.01), but increased IL-8 release induced by a dust supernatant by 13% (P<0.05). In summary, expression of the cytokines IL-6 and IL-8 is differentially regulated by 8-Bromo-cAMP, both with regard to basal and dust-induced release. The results indicate that 8-Bromo-cAMP attenuated IL-8 release by affecting signaling transductions induced by the particulate fraction.     

Lafutidine inhibits Helicobacter pylori-induced interleukin-8 production in human gastric epithelial cells

BACKGROUND AND AIM: Attachment of Helicobacter pylori to gastric epithelial cells leads to the production of chemokines, such as interleukin-8 (IL-8), which in turn activate and recruit neutrophils to the site of infection. Lafutidine [(+/-)-2-(furfurylsulfinyl)-N-(4-(4-(piperidinomethyl)-2-pyridyl)oxy-(Z)-2-butenyl)acetamide] is a new type of antiulcer drug that possesses an antisecretory action as well as gastroprotective activity, independent of its antisecretory action. In the present study, we examined the effects of lafutidine on H. pylori-induced IL-8 release and H. pylori adhesion to MKN45 cells. METHODS: MKN45 cells were stimulated with H. pylori, tumor necrosis factor (TNF)-alpha, or IL-1beta, then IL-6 and IL-8 levels in the culture supernatants were determined with a specific enzyme-linked immunosorbent assay kit. RESULTS: Lafutidine significantly inhibited both the release of IL-8 induced by H. pylori and the adhesion of H. pylori to cells in a dose-dependent manner. These properties of lafutidine are unrelated to the blockade of histamine H(2)-receptors, because the same effects have not been observed with other H(2)-receptor antagonists, such as cimetidine and famotidine. Lafutidine also significantly inhibited H. pylori-induced IL-6 release. Both TNF-alpha and IL-1beta-induced IL-8 releases, conversely, were little affected by lafutidine up to a concentration of 10(-5) M. CONCLUSIONS: These results suggest that lafutidine inhibits IL-8 release by inhibiting H. pylori adherence to gastric epithelial cells, indicating a novel mechanism by which lafutidine protects against the mucosal inflammation associated with H. pylori infection.     

Immunization of humans with recombinant pneumococcal surface protein A (rPspA) elicits antibodies that passively protect mice from fatal infection with Streptococcus pneumoniae bearing heterologous PspA

Pneumococcal surface protein A (PspA), a cross-reactive protein expressed by all pneumococci, is known to elicit an antibody in animals that can passively protect mice from infection with Streptococcus pneumoniae. A phase I trial with recombinant PspA showed the protein to be immunogenic in humans. Pre- and postimmune serum samples from this trial were examined, and human antibody to PspA could protect mice from pneumococcal infection. The serum samples of subjects immunized twice with 125 microg of PspA had >100 times as much antibody per milliliter as was required to consistently protect mice from fatal infection (1.3 microg/dose). At least 98% of PspAs fall into PspA sequence/serologic families 1 or 2. Human antibodies elicited by a family 1 PspA protected against infection with S. pneumoniae expressing either family 1 or 2 PspAs and with strains of all 3 capsular types tested: 3, 6A, and 6B. These studies suggest that PspA may have efficacy as a human vaccine.     

Infection of replication-deficient adenoviral vector enhances interleukin-8 production in small airway epithelial cells more than in large airway epithelial cells

OBJECTIVE: In clinical trials or experiments of gene therapy, airway administration of an adenoviral-based vector (E1A-deleted) elicits a dose-dependent inflammatory response with limitation in the duration of transgene expression. The purpose of this study was to evaluate the possibility that the adenoviral-based vector directly enhances IL-8 production independent of adenoviral E1A in normal human airway epithelial cells and to examine the different responses between primary human bronchial epithelial cells (HBE) and primary human small airway epithelial cells (HSAE) in production of IL-8 following exposure to an adenovirus vector. METHODOLOGY: Interleukin (IL)-8 levels were evaluated in the culture medium from HBE and HSAE treated with increasing doses of E1A-deleted adenoviral vector contained the Escherichia coli LacZ reporter gene (AdCMVLacZ). To clarify the mechanism of enhancing IL-8 production in airway epithelial cells by infection with adenovirus vector, alphavbeta5 agonistic antibody as an analogue of adenoviral capsid and adenoviral capsid vector denatured by exposure to ultraviolet (UV) light were used in the present study. RESULTS: Inoculation of HBE with AdCMVLacZ at a multiplicity of infection (MOI) of between 1 and 200 resulted in a dose-dependent expression of LacZ, and maximal expression was observed at a MOI of 100. In contrast, inoculation of HSAE with AdCMVLacZ resulted in maximum expression of LacZ at a MOI of 10. Interleukin-8 levels in culture media from the same experiments revealed significantly greater production of IL-8 in HSAE inoculated with AdCMVLacZ at a MOI of 50, compared to HBE under the same conditions. The capsid-denatured adenoviral vector did not enhance IL-8 production, and alphavbeta5 agonistic antibody induced IL-8 enhancement. CONCLUSION: These results suggest that the adenoviral vector directly induces the expression of airway epithelial inflammatory cytokines in the pathogenesis of inflammation and that small airway cells have a greater affinity for adenovirus than other airway epithelial cells.     

Cyclic stretch upregulates interleukin-8 and transforming growth factor-beta1 production through a protein kinase C-dependent pathway in alveolar epithelial cells

OBJECTIVE: Positive-pressure mechanical ventilation can injure the lung, causing oedema and alveolar inflammation, which is termed 'ventilator-induced lung injury' (VILI). We postulated that cyclic stretch upregulates the release of cytokines, which may cause lung damage, and explored which cytokines were released after cyclic stretch in type II alveolar epithelial cells (A549). METHODOLOGY: To test this hypothesis, A549 cells were cultured on a silicoelastic membrane and interleukin (IL)-1beta, IL-8, granulocyte-macrophage colony stimulating factor, activin, transforming growth factor (TGF)-beta1, insulin-like growth factor-2 and tumour necrosis factor-alpha mRNA and protein were assessed after stimulation of the cells by cyclic stretch. RESULTS: Cyclic stretch induced activation of protein kinase C and resulted in the release of IL-8 and TGF-beta1 from A549 cells. CONCLUSIONS: The release of IL-8 and TGF-beta1 from alveolar epithelial cells may be a contributing factor in alveolitis associated with VILI.     

Differential alveolar epithelial injury and protein expression in pneumococcal pneumonia

The integrity of the alveolar epithelium is a key factor in the outcome of acute lung injury. Here, we investigate alveolar epithelial injury and the expression of epithelial-selective markers in Streptococcus pneumoniae-induced acute lung injury. S. pneumoniae was instilled into rat lungs and alveolar type I (RTI(40)/podoplanin, MMC6 antigen) and alveolar type II (MMC4 antigen, surfactant protein D, pro-surfactant protein C, RTII(70)) cell markers were quantified in lavage fluid and lung tissue at 24 and 72 hours. The alveolar epithelium was also examined using electron, confocal, and light microscopy. S. pneumoniae induced an acute inflammatory response as assessed by increased total protein, SP-D, and neutrophils in lavage fluid. Biochemical and morphological studies demonstrated morphologic injury to type II cells but not type I cells. In particular, the expression of RTI(40)/podoplanin was dramatically reduced, on the surface of type I cells, in the absence of morphologic injury. These data demonstrate that type II cell damage can occur in the absence of type I cell injury without affecting the ability of the lung to return to a normal morphology. These data also demonstrate that RTI(40)/podoplanin is not a type I cell phenotypic marker in experimental acute lung injury caused by S. pneumoniae. Given that RTI(40)/podoplanin is an endogenous ligand for the C-type lectin receptor and this receptor plays a role in platelet aggregation and neutrophil activation, we hypothesize that the reduction of RTI(40)/podoplanin on type I cells might be important for the regulation of platelet and/or neutrophil function in experimental acute lung injury.     

Human thymic epithelial cells produce interleukin-3

Interleukin-3 (IL-3) is a hematopoietic growth factor suggested to be produced by activated T lymphocytes. Meanwhile, supernatants from human thymic stroma could promote the proliferation of myeloid stem cells. Thus, we investigated whether IL-3 accounts for this activity. Therefore, human thymic epithelial cells (TEC), fibroblasts, and adherent cells were isolated, and their culture supernatants assayed for myeloid colony promotion. Only supernatants from thymic epithelial cells supported colony-forming unit growth in semisolid media. This effect decreased following anti-IL-3 monoclonal antibody addition to these cultures. Furthermore, in situ hybridization showed the presence of IL-3 mRNA in epithelial cells. Effect of TEC culture conditions on IL-3 production by these cells was also studied. Together, these data show that IL-3 production is not the exclusive property of human activated T lymphocytes.     

Effect of Mycoplasma pneumoniae lysate on interleukin-8 gene expression in human respiratory epithelial cells

STUDY OBJECTIVES: Mycoplasma pneumoniae is a common cause of lower respiratory disease. Several studies have suggested that respiratory infection by M pneumoniae is associated with reactive airway disease and asthma. Interleukin (IL)-8 has been suggested to have a role in the pathogenesis of the allergic inflammation of bronchial asthma, and is well known to be expressed in bronchial epithelial cells. MEASUREMENTS: An examination was carried out into the effect of M pneumoniae lysate (MPL) and the role of mitogen-activated protein kinases (MAPKs) and extracellular signal-regulated kinase (ERK) on IL-8 expression in human lung epithelial cells. A549 cells were seeded at a density of 5 x 10(4) cells per well and incubated in basal medium for a further 24 h. IL-8 levels were determined by an enzyme-linked immunosorbent assay. MAPK phosphorylation was assessed by Western blotting. RESULTS: In A549 cells, MPL induced IL-8 release in a time- and dose-dependent manner. Pretreatment with PD 98059, which blocks the activation of MAPK/ERK kinase 1, inhibited MPL-induced IL-8 production by 64.4% at 25 micromol/L. Stimulation of A549 cells by MPL also caused an increase in the activity of ERK, compared with the nonstimulated cells. The MPL stimulation had no effect on the activities of p38. CONCLUSION: These observations suggest that activation of ERK by MPL may be one of the mechanisms that result in an increase of the production of IL-8.     

过氧化氢上调白细胞介素1β诱导人肺上皮细胞表达环氧合酶2

目的探讨过氧化氢(H2O2)对白细胞介素1β(IL-1β)诱导人肺上皮细胞(HPEC)环氧合酶2(COX-2)表达的影响.方法应用逆转录-聚合酶链反应(RT-PCR)半定量法和酶联免疫吸附试验 (ELISA)测定IL-1β、H2O2或二者联合干预后HPEC COX-2 mRNA表达量及前列腺素E2(PGE2)释放量的变化, 以不加任何试剂的细胞为对照组.结果 (1)COX-2 mRNA表达量1、5、10 mg/L 的IL-1β处理组COX-2 mRNA表达量分别为(143.1±7.2)%、(179.9±9.0)%、(190.0±9.5)%,对照组为(32.9±1.7)%,1、5、10 mg/L 的IL-1β处理组与对照组比较差异有显著性(P均<0.05); (2)培养基上清液PGE2浓度5、10 mg/L 的IL-1β处理组培养基上清液PGE2浓度分别为 (20.86±5.23)×10-6 g/L、(31.16±2.64)×10-6 g/L,对照组为(10.49±0.36)×10-6 g/L, 5、10 mg/L 的IL-1β处理组与对照组比较差异有显著性(P<0.05);(3) COX-2 mRNA表达量 0.10、0.25、0.50 mmol/L 的H2O2和IL-1β共处理组COX-2 mRNA表达量分别为 (149.2±7.5)%、(189.6±9.5)%、(239.1±12.0)%, IL-1β单独处理组为(66.1±3.7)%, 对照组为(41.6±2.1)%, 0.10、0.25、0.50 mmol/L 的H2O2和IL-1β共处理组与IL-1β单独处理组比较,差异有显著性 (P<0.05); (4)培养基上清液PGE2浓度0.10、0.25、0.50 mmol/L的H2O2和IL-1β共处理组,培养基上清液PGE2浓度分别为 (27.01±5.16)×10-6 g/L、(32.79±3.01)×10-6 g/L、(41.13±3.41)×10-6 g/L,对照组为(10.49±0.36)×10-6 g/L,0.10、0.25、0.50 mmol/L的H2O2和IL-1β共处理组与对照组比较差异有显著性(P<0.05).0.25、0.50 mmol/L的 H2O2和IL-1β共处理组PGE2浓度均与IL-1β单独处理组[(20.86±5.23)×10-6 g/L]比较差异有显著性 (P<0.05). 结论过氧化氢上调IL-1β对HPEC COX-2的诱导表达,其调节机制可能发生在转录水平.     

中国幽门螺杆菌胃上皮细胞白细胞介素-8的转录能力

目的探讨中国幽门螺杆菌(Hp)的空泡毒素基因(vacA)型及cag致病岛对胃上皮细胞白细胞介素-8(IL-8)转录的影响.方法以基因测序与Southern杂交法确定HpvacA基因型及cag致病岛状态;构建带有IL-8报告基因的人胃癌细胞系L5F11,用液体闪烁计数仪测定荧光素酶活性(IL-8转录),用HeLa细胞测定空泡毒素活性.结果所有cag致病岛完整菌株(15株)较野生型cag致病岛阴性菌株G50诱导荧光素酶活性[记数/分(cpm)]明显增强[(0.47±0.19)×106cpm比(0.13±0.02)×106cpm,P＜0.01];而cag致病岛部分丢失菌株(4株)荧光素酶活性与G50差异无显著性[(0.23±0.08)×106cpm比(0.13±0.02)×106cpm,P＞0.05];vacA基因s1/m1型菌株(5株)较s1/m2型菌株(14株)空泡毒素活性增强(P＜0.01),但二者诱导荧光素酶活性差异无显著性[(0.29±0.12)×106cpm比(0.53±0.41)×106cpm,P＞0.05].结论中国Hp诱导胃上皮细胞IL-8转录能力与cag致病岛状态密切相关,而与vacA基因型无明显关系.     

与白介素8有关的炎症细胞在慢性阻塞性肺疾病中研究进展

慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)它在世界范围内的高发病率和病死率是导致巨大经济和社会负担的主要原因.近期研究表明,白介素8(interleukin-8,IL-8)与COPD的发生密切相关.IL-8作为主要的炎性递质参与了介导气道炎症反应,加速局部炎...     

Infant formula alters surfactant protein A (SP-A) and SP-B expression in pulmonary epithelial cells

Surfactant proteins A (SP-A) and SP-B are critical in the ability of pulmonary surfactant to reduce alveolar surface tension and provide innate immunity. Aspiration of infant milk formula can lead to lung dysfunction, but direct effects of aspirated formula on surfactant protein expression in pulmonary cells have not been described. The hypothesis that infant formula alters surfactant protein homeostasis was tested in vitro by assessing surfactant protein gene expression in cultured pulmonary epithelial cell lines expressing SP-A and SP-B that were transiently exposed (6 hr) to infant formula. Steady-state levels of SP-A protein and mRNA and SP-B mRNA in human bronchiolar (NCI-H441) and mouse alveolar (MLE15) epithelial cells were reduced in a dose-dependent manner 18 hr after exposure to infant formula. SP-A mRNA levels remained reduced 42 hr after exposure, but SP-B mRNA levels increased 10-fold. Neither soy formula nor non-fat dry milk affected steady-state SP-A and SP-B mRNA levels; suggesting a role of a component of infant formula derived from cow milk. These results indicate that infant formula has a direct, dose-dependent effect to reduce surfactant protein gene expression. Ultimately, milk aspiration may potentially result in a reduced capacity of the lung to defend against environmental insults.