共查询到20条相似文献,搜索用时 15 毫秒
1.
F Finetti E Terzuoli E Bocci I Coletta L Polenzani G Mangano MA Alisi N Cazzolla A Giachetti M Ziche S Donnini 《PloS one》2012,7(7):e40576
Background
Blockade of Prostaglandin (PG) E2 production via deletion of microsomal Prostaglandin E synthase-1 (mPGES-1) gene reduces tumor cell proliferation in vitro and in vivo on xenograft tumors. So far the therapeutic potential of the pharmacological inhibition of mPGES-1 has not been elucidated. PGE2 promotes epithelial tumor progression via multiple signaling pathways including the epidermal growth factor receptor (EGFR) signaling pathway.Methodology/Principal Findings
Here we evaluated the antitumor activity of AF3485, a compound of a novel family of human mPGES-1 inhibitors, in vitro and in vivo, in mice bearing human A431 xenografts overexpressing EGFR. Treatment of the human cell line A431 with interleukin-1beta (IL-1β) increased mPGES-1 expression, PGE2 production and induced EGFR phosphorylation, and vascular endothelial growth factor (VEGF) and fibroblast growth factor-2 (FGF-2) expression. AF3485 reduced PGE2 production, both in quiescent and in cells stimulated by IL-1β. AF3485 abolished IL-1β-induced activation of the EGFR, decreasing VEGF and FGF-2 expression, and tumor-mediated endothelial tube formation. In vivo, in A431 xenograft, AF3485, administered sub-chronically, decreased tumor growth, an effect related to inhibition of EGFR signalling, and to tumor microvessel rarefaction. In fact, we observed a decrease of EGFR phosphorylation, and VEGF and FGF-2 expression in tumours explanted from treated mice.Conclusion
Our work demonstrates that the pharmacological inhibition of mPGES-1 reduces squamous carcinoma growth by suppressing PGE2 mediated-EGFR signalling and by impairing tumor associated angiogenesis. These results underscore the potential of mPGES-1 inhibitors as agents capable of controlling tumor growth. 相似文献2.
《Biochimica et Biophysica Acta (BBA)/General Subjects》2020,1864(10):129672
BackgroundExposure to PM2.5 has been associated with increased morbidity and mortality of lung diseases although the underlying mechanisms have not been fully uncovered. Airway inflammation is a critical event in the pathogenesis of lung diseases. This study aimed to examine the role of oxidative stress and epidermal growth factor receptor (EGFR) in PM2.5-induced pro-inflammatory response in a human bronchial epithelial cell line, BEAS-2B.MethodsBEAS-2B cells were exposed to 0, 20, 50, 100 and 150 μg/ml of PM2.5. Secretion of pro-inflammatory mediators including interleukin-6 (IL-6), IL-8 and IL-1β was determined using enzyme linked immunosorbent assay. Levels of intracellular reactive oxygen species (ROS) were determined using flow cytometry. Phosphorylation of the EGFR was examined with immunoblotting.ResultsPM2.5 exposure increased the secretion of IL-6, IL-8, and IL-1β in a concentration-dependent fashion. Moreover, exposure to PM2.5 elevated intracellular levels of ROS, and phosphorylation of the EGFR (Y1068). Pretreatment of BEAS-2B cells with either an antioxidant or a specific EGFR inhibitor significantly reduced PM2.5-induced IL-6, IL-8 and IL-1β secretion, implying that both oxidative stress and EGFR activation were involved in PM2.5-induced pro-inflammatory response. Furthermore, pre-treatment of BEAS-2B cells with an antioxidant significantly blunted PM2.5-induced EGFR activation, suggesting that oxidative stress was required for PM2.5-induced EGFR activation.ConclusionPM2.5 exposure induces pro-inflammatory response in human bronchial epithelial cells through oxidative stress-mediated EGFR activation. 相似文献
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Pace E Ferraro M Minervini MI Vitulo P Pipitone L Chiappara G Siena L Montalbano AM Johnson M Gjomarkaj M 《PloS one》2012,7(3):e33601
Background
Altered pulmonary defenses in chronic obstructive pulmonary disease (COPD) may promote distal airways bacterial colonization. The expression/activation of Toll Like receptors (TLR) and beta 2 defensin (HBD2) release by epithelial cells crucially affect pulmonary defence mechanisms.Methods
The epithelial expression of TLR4 and of HBD2 was assessed in surgical specimens from current smokers COPD (s-COPD; n = 17), ex-smokers COPD (ex-s-COPD; n = 8), smokers without COPD (S; n = 12), and from non-smoker non-COPD subjects (C; n = 13).Results
In distal airways, s-COPD highly expressed TLR4 and HBD2. In central airways, S and s-COPD showed increased TLR4 expression. Lower HBD2 expression was observed in central airways of s-COPD when compared to S and to ex-s-COPD. s-COPD had a reduced HBD2 gene expression as demonstrated by real-time PCR on micro-dissected bronchial epithelial cells. Furthermore, HBD2 expression positively correlated with FEV1/FVC ratio and inversely correlated with the cigarette smoke exposure. In a bronchial epithelial cell line (16 HBE) IL-1β significantly induced the HBD2 mRNA expression and cigarette smoke extracts significantly counteracted this IL-1 mediated effect reducing both the activation of NFkB pathway and the interaction between NFkB and HBD2 promoter.Conclusions
This study provides new insights on the possible mechanisms involved in the alteration of innate immunity mechanisms in COPD. 相似文献5.
Agnes W. Boots Milena Hristova David I. Kasahara Guido R. M. M. Haenen Aalt Bast Albert van der Vliet 《The Journal of biological chemistry》2009,284(26):17858-17867
Activation of the NADPH oxidase homolog dual oxidase 1 (DUOX1) within the airway epithelium represents a key mechanism of innate airway host defense, through enhanced production of H2O2, which mediates cellular signaling pathways that regulate the production of various inflammatory mediators. Production of the CXC chemokine interleukin (IL)-8/CXCL8 forms a common epithelial response to many diverse stimuli, including bacterial and viral triggers, environmental oxidants, and other biological mediators, suggesting the potential involvement of a common signaling pathway that may involve DUOX1-dependent H2O2 production. Following previous reports showing that DUOX1 is activated by extracellular ATP and purinergic receptor stimulation, this study demonstrates that airway epithelial IL-8 production in response to several bacterial stimuli involves ATP release and DUOX1 activation. ATP-mediated DUOX1 activation resulted in the activation of ERK1/2 and NF-κB pathways, which was associated with epidermal growth factor receptor (EGFR) ligand shedding by ADAM17 (a disintegrin and metalloproteinase-17). Although ATP-mediated ADAM17 activation and IL-8 release were not prevented by extracellular H2O2 scavenging by catalase, these responses were attenuated by intracellular scavengers of H2O2 or related oxidants, suggesting an intracellular redox signaling mechanism. Both ADAM17 activation and IL-8 release were suppressed by inhibitors of EGFR/ERK1/2 signaling, which can regulate ADAM17 activity by serine/threonine phosphorylation. Collectively, our results indicate that ATP-mediated DUOX1 activation represents a common response mechanism to several environmental stimuli, involving H2O2-dependent EGFR/ERK activation, ADAM17 activation, and EGFR ligand shedding, leading to amplified epithelial EGFR activation and IL-8 production. 相似文献
6.
Takafumi Matsumoto Yosuke Sato Takako Nakano Miyuki Eguchi-Tsuda Keiko Kan-o Takao Shimizu Shohei Sakuda Yoichi Nakanishi 《Biochemical and biophysical research communications》2009,390(1):103-79
Acidic mammalian chitinase is upregulated in response to allergen exposure in the lung. We investigated the effects of chitinase inhibitors, allosamidin (Allo) and demethylallosamidin (Dma), on asthmatic responses. Mice were subjected to IL-13 instillation into the airways or to ovalbumin sensitization plus exposure with or without treatment of Allo or Dma. Airway hyperresponsiveness (AHR) and inflammation were evaluated. Allo and Dma attenuated airway eosinophilia and the upregulation of eotaxin after IL-13 instillation, while Dma, but not Allo, suppressed AHR in IL-13-induced asthma. Allo or Dma suppressed the elevated chitinase activity in BAL fluids after IL-13 to similar levels. The bronchoprotective PGE2 levels in BAL fluids were elevated after IL-13 instillation. Allo, but not Dma, suppressed the overproduction of PGE2 and the expression of COX-2 and PGE synthase-1 induced by IL-13. In ovalbumin-induced asthma, Dma suppressed AHR more strongly than Allo. These findings suggest that Dma attenuates asthmatic responses induced by IL-13 without affecting PGE2 synthesis. Dma may have potential as therapeutic agents for asthma. 相似文献
7.
Kiritikara Kanyawim Laulederkind Stanley J. F. Raghow Rajendra Kanekura Takuro Ballou Leslie R. 《Molecular and cellular biochemistry》1998,188(1-2):41-48
Interleukin-1 (IL-1) is a potent inducer of prostaglandin E2 (PGE2) synthesis. We previously showed that ceramide accumulates in fibroblasts treated with IL-1 and that it enhances IL-1-induced PGE2 production. The present study was undertaken to determine the mechanism(s) by which ceramide and IL-1 interact to enhance PGE2 production by examining their respective effects on the rate-limiting enzymes in PGE2 synthesis, cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and cytosolic phospholipase A2 (cPLA2). IL-1-induced PGE2 synthesis required 8 h even though COX-1 was constitutively expressed (both mRNA and protein) and enzymatically active in untreated cells. Conversely, COX-2 mRNA was barely detectable in untreated cells but within 2 h, ceramide or IL-1 alone induced a 5 and 20 fold increase in COX-2 mRNA, respectively. However, IL-1 induced COX-2 protein synthesis was only detectable 6-7 h after maximal COX-2 mRNA induction; COX-2 protein accumulation was not induced by ceramide alone. Ceramide however, reduced the length of time required for IL- 1 to induce COX-2 protein accumulation and increased COX-2 protein accumulation. IL-1 induced a 15 fold increase in COX-1 mRNA including an alternatively spliced form of COX-1. IL-1, but not ceramide induced cPLA2 mRNA and protein expression which corresponded with the initiation of PGE2 synthesis. These observations indicate that, (1) while either ceramide or IL-1 rapidly induced COX-2 mRNA, COX-2 protein only accumulated in IL- 1 treated cells after a delay of 6-7 h, (2) IL-1-induced PGE2 synthesis required both COX-2 and cPLA2 protein synthesis and, (3) ceramide enhanced (temporally and quantitatively) IL-1-induced COX-2 protein accumulation resulting in enhanced PGE2 production. 相似文献
8.
Nakanaga T Nadel JA Ueki IF Koff JL Shao MX 《American journal of physiology. Lung cellular and molecular physiology》2007,292(5):L1289-L1296
Airways function as an innate immune organ against airborne bacteria that are inhaled and deposited in airways. One of the mechanisms of host defense is to recruit neutrophils into airways to clear the invaders. Airway epithelial cells produce neutrophil chemoattractant interleukin (IL)-8 in response to invading bacteria. In this study we show a signaling pathway on the plasma surface of human airway epithelial NCI-H292 cells that regulate IL-8 production in response to a model inflammatory stimulus, phorbol 12-myristate 13-acetate, and a pathophysiological stimulus, gram-negative bacterial lipopolysaccharide. First, we show that EGF receptor (EGFR) and MAP kinase ERK1/2 are involved in IL-8 expression by these stimuli. Second, we show that EGFR ligand transforming growth factor (TGF)-alpha mediates IL-8 production. Third, we show that tumor necrosis factor-alpha-converting enzyme (TACE) is required for IL-8 production by cleaving EGFR proligand proTGF-alpha into soluble TGF-alpha, activating EGFR. Last, we show that dual oxidase 1 (Duox1), a homolog of NADPH oxidase in airways, mediates TACE activation and IL-8 expression via generation of reactive oxygen species. In summary, we describe a signaling pathway, Duox1-TACE-TGF-alpha-EGFR, on the surface of airway epithelial (NCI-H292) cells that mediates airway epithelial defense against bacterial infection by producing IL-8. This pathway, which also regulates mucin production in human airways, provides mechanisms for killing foreign organisms and for their clearance. 相似文献
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Background
Cervical cancer is a chronic inflammatory disease of multifactorial etiology usually presenting in sexually active women. Exposure of neoplastic cervical epithelial cells to seminal plasma (SP) has been shown to promote the growth of cancer cells in vitro and tumors in vivo by inducing the expression of inflammatory mediators including pro-inflammatory cytokines. IL-1α is a pleotropic pro-inflammatory cytokine induced in several human cancers and has been associated with virulent tumor phenotype and poorer prognosis. Here we investigated the expression of IL-1α in cervical cancer, the role of SP in the regulation of IL-1α in neoplastic cervical epithelial cells and the molecular mechanism underlying this regulation.Methods and results
Real-time quantitative RT-PCR confirmed the elevated expression of IL-1α mRNA in cervical squamous cell carcinoma and adenocarcinoma tissue explants, compared with normal cervix. Using immunohistochemistry, IL-1α was localized to the neoplastically transformed squamous, columnar and glandular epithelium in all cases of squamous cell carcinoma and adenocarcinomas explants studied. We found that SP induced the expression of IL-α in both normal and neoplastic cervical tissue explants. Employing HeLa (adenocarcinoma) cell line as a model system we identified PGE2 and EGF as possible ligands responsible for SP-mediated induction of IL-1α in these neoplastic cells. In addition, we showed that SP activates EP2/EGFR/PI3kinase-Akt signaling to induce IL-1α mRNA and protein expression. Furthermore, we demonstrate that in normal cervical tissue explants the induction of IL-1α by SP is via the activation of EP2/EGFR/PI3 kinase-Akt signaling.Conclusion
SP-mediated induction of IL-1α in normal and neoplastic cervical epithelial cells suggests that SP may promote cervical inflammation as well as progression of cervical cancer in sexually active women.11.
Ewa Selg Margareta Andersson Lena Låstbom Åke Ryrfeldt Sven-Erik Dahlén 《Prostaglandins & other lipid mediators》2009,88(3-4):101-110
Leukotriene D4 (LTD4)-induced bronchoconstriction in guinea-pig airways has a cyclooxygenase (COX)-dependent component. The main objective of this study was to establish if prostaglandin (PG) D2-induced bronchoconstriction also was modulated by COX products. The effects of non-selective and selective COX-1 and COX-2 inhibitors on bronchoconstriction induced by LTD4 and PGD2 were investigated in the perfused and ventilated guinea-pig lung (IPL). Both LTD4-induced bronchoconstriction and thromboxane (TX) A2 release was suppressed by COX inhibitors or by TX synthesis inhibition. The release of additional COX products following CysLT1 receptor activation by LTD4 was established by measurements of immunoreactive 6-keto PGF1α (a stable metabolite of PGI2) and PGE2. In contrast, TP receptor-mediated bronchoconstriction by PGD2 was somewhat enhanced by COX inhibitors, and there was no measurable release of COX products after TP receptor activation with U-46619. PGE2 was bronchoprotective in IPL as it inhibited the histamine-induced bronchoconstriction. In the isolated guinea-pig trachea, neither PGD2 nor U-46619 actively released PGE2, but continuous production of PGE2 and PGI2 was established, and the response to PGD2 was enhanced also in the trachea by COX inhibition. The study documented that bronchoconstriction induced by LTD4 and PGD2 in IPL was modulated differently by COX products. Whereas bronchoconstriction induced by LTD4 was amplified predominantly by secondarily released TXA2, that induced by PGD2 was attenuated by bronchoprotective PGE2 and PGI2, presumably tonically produced in the airways. 相似文献
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In this study, gallic acid-conjugated chitooligosaccharides (gallate-COS) was evaluated for its enhancing capabilities in free radical scavenging and anti-inflammatory activities in human lung epithelial A549 cells. It was found that gallate-COS possesses significantly high DPPH radical scavenging activity and protective effect against H2O2-induced DNA damage. Likewise, gallate-COS decreased the production of intracellular reactive oxygen species in H2O2-stimulated A549 cells. Moreover, the suppressive effects of gallate-COS on COX-2 expression and PGE2 production from LPS-stimulated A549 cells were evidenced. Finally, the productions of cytokines including IL-8 and TNF-α were also inhibited by gallate-COS in a dose-dependent manner. Collectively, these results suggest that gallate-COS could be used as a functional ingredient with potent antioxidant and anti-inflammatory benefits. 相似文献
14.
Lin CC Sun CC Luo SF Tsai AC Chien CS Hsiao LD Lee CW Hsieh JT Yang CM 《Journal of biomedical science》2004,11(3):377-390
Interleukin-1 (IL-1) has been recognized as a potent stimulus for the synthesis of prostaglandin (PG), which has been implicated in inflammatory responses of the airways. However, the mechanisms underlying IL-1-induced cyclooxygenase (COX) expression and PGE2 synthesis via activation of p42/p44 and p38 mitogen-activated protein kinases (MAPKs) in human tracheal smooth muscle cells (HTSMCs) are not completely understood. We found that IL-1 increased COX-2 expression and PGE2 synthesis in time- and concentration-dependent manners. Both specific phosphatidylcholine-phospholipase C inhibitor (D609) and protein kinase C inhibitor (GF109203X) attenuated IL-1-induced responses in HTSMCs. IL-1-induced COX-2 expression and PGE2 synthesis were also inhibited by an inhibitor of MEK1/2 (PD98059) and inhibitors of p38 MAPK (SB203580 and SB202190), respectively, suggesting the involvement of p42/p44 and p38 MAPKs in these responses. This hypothesis was further supported by the transient activation of p42/p44 and p38 MAPKs induced by IL-1. Furthermore, IL-1-induced activation of nuclear factor-B (NF-B) was inversely correlated with the degradation of IB- in HTSMCs. IL-1-induced COX-2 expression and PGE2 synthesis were inhibited by the NF-B inhibitor pyrrolidinedithiocarbamate. These findings suggest that the expression of COX-2 is correlated with the release of PGE2 from IL-1-challenged HTSMCs, which is mediated, at least in part, through p42/p44 and p38 MAPKs and NF-B signaling pathways in HTSMCs. 相似文献
15.
Ozone-induced pulmonary inflammation and epithelial proliferation are partially mediated by PAF 总被引:2,自引:0,他引:2
Longphre M.; Zhang L.-Y.; Harkema J. R.; Kleeberger S. R. 《Journal of applied physiology》1999,86(1):341-349
Ozone(O3) exposure stimulates airwayinflammation and epithelial sloughing in a number of species, includingmice. Platelet-activating factor (PAF) is a lipid mediator released byactivated mast cells, macrophages, and epithelial cells and causespulmonary inflammation and hyperpermeability. We hypothesized that theactivation of PAF receptors is central to the development ofinflammation and epithelial injury induced by acuteO3 exposure in mice. To test thishypothesis, O3-susceptibleC57BL/6J mice were treated with a PAF-receptor antagonist, UK-74505, orvehicle either before or immediately after 3-h exposure toO3 (2 parts/million) or filtered air. Bronchoalveolar lavage (BAL) fluids were collected 6 and 24 hafter exposure. Differential cell counts and protein content of thelavage were used as indicators of inflammation in the airways. O3-induced epithelial injury wasassessed by light microscopy, and DNA synthesis in epithelium ofterminal bronchioles was estimated by using abromodeoxyuridine-labeling index. Intercellular adhesion molecule 1 (ICAM-1) expression was also examined in the lung by immunohistochemical localization.O3 caused significant increases inpolymorphonuclear leukocytes and protein in the BAL fluid, increasedpulmonary epithelial proliferation, and increased epithelial expressionof ICAM-1 compared with air-exposed, vehicle-treated control mice.Relative to O3-exposed,vehicle-treated control mice, UK-74505 before exposure significantly(P < 0.05) decreased BAL protein,polymorphonuclear leukocytes, and epithelial cells. O3-induced inflammation wassimilarly attenuated in mice treated with UK-74505 after exposure.These experiments thus support the hypothesis thatO3-induced airways inflammationand epithelial damage in mice are partially mediated by activation ofPAF receptors, possibly through modulation of ICAM-1 expression. 相似文献
16.
Philippe Dje N'Guessan Helge Haarmann Tamara Steiner Kerstin Heyl Frauke Schreiber Annina Heinrich Hortense Slevogt 《Biochemical and biophysical research communications》2014
Background
Chronic lower airway inflammation is considered to be a major cause of pathogenesis and disease progression in chronic obstructive pulmonary disease (COPD). Moraxella catarrhalis is a COPD-associated pathogen causing exacerbations and bacterial colonization in the lower airways of patients, which may contribute to chronic inflammation. Increasing evidence suggests that the epidermal growth factor receptor (EGFR) modulates inflammatory processes in the human airways. The goal of this study was to investigate the role of EGFR in the M. catarrhalis-induced pro-inflammatory immune response in airway epithelial cells.Methods
The effects of inhibition and gene silencing of EGFR on M. catarrhalis-dependent pro-inflammatory cytokine expression in human primary bronchial epithelial cells (NHBEs), as well as the pulmonary epithelial cell lines BEAS-2B and A549 were analyzed. We also assessed the involvement of EGFR-dependent ERK and NF-κB signaling pathways.Results
The M. catarrhalis-induced pro-inflammatory immune response depends, at least in part, on the phosphorylation and activation of the EGF receptor. Interaction of M. catarrhalis with EGFR increases the secretion of pro-inflammatory cytokines, which is mediated via ERK and NF-κB activation.Conclusion
The interaction between M. catarrhalis and EGFR increases airway inflammation caused by this pathogen. Our data suggest that the inhibition of EGFR signaling in COPD could be an interesting target for reducing M. catarrhalis-induced airway inflammation. 相似文献17.
Haruhiko Tokuda Osamu Kozawa Atsushi Harada Toshihiko Uematsu 《Journal of cellular biochemistry》1998,69(3):252-259
In previous studies, we have reported that PGF2α stimulates phosphoinositide hydrolysis by phospholipase C and phosphatidylcholine hydrolysis by phospholipase D through heterotrimeric GTP-binding protein in osteoblast-like MC3T3-E1 cells, and that PGF2α and PGE1 induce interleukin-6 (IL-6) synthesis via activation of protein kinase C and protein kinase A, respectively. In the present study, we investigated the effect of tiludronate, a bisphosphonate known to inhibit bone resorption, on the PGF2α- and PGE1-induced IL-6 synthesis in these cells. Tiludronate significantly suppressed the PGF2α-induced IL-6 secretion in a dose-dependent manner in the range between 0.1 and 30 μM. However, the IL-6 secretion induced by PGE1 or (Bu)2cAMP was hardly affected by tiludronate. The choline formation induced by PGF2α was reduced by tiludronate dose-dependently in the range between 0.1 and 30 μM. On the contrary, tiludronate had no effect on PGF2α-induced formation of inositol phosphates. Tiludronate suppressed the choline formation induced by NaF, known as an activator of heterotrimeric GTP-binding protein. However, tiludronate had little effect on the formation of choline induced by TPA, a protein kinase C activator. Tiludronate significantly inhibited the NaF-induced IL-6 secretion in human osteoblastic osteosarcoma Saos-2 cells. These results strongly suggest that tiludronate inhibits PGF2α-induced IL-6 synthesis via suppression of phosphatidylcholine-hydrolyzing phospholipase D activation in osteoblasts, and that the inhibitory effect is exerted at the point between heterotrimeric GTP-binding protein and phospholipase D. J. Cell. Biochem. 69:252–259, 1998. © 1998 Wiley-Liss, Inc. 相似文献
18.
Cassiano Felippe Gon?alves-de-Albuquerque Patrícia Burth Adriana Ribeiro Silva Isabel Matos Medeiros de Moraes Flora Magno de Jesus Oliveira Ricardo Erthal Santelli Aline Soares Freire Gerson Silva de Lima Emilson Domingos da Silva Camila Ignácio da Silva Ver?nica Morandi Patrícia Torres Bozza Mauricio Younes-Ibrahim Hugo Caire de Castro Faria Neto Mauro Velho de Castro Faria 《Respiratory research》2014,15(1)
Background
Leptospiral glycolipoprotein (GLP) is a potent and specific Na/K-ATPase inhibitor. Severe pulmonary form of leptospirosis is characterized by edema, inflammation and intra-alveolar hemorrhage having a dismal prognosis. Resolution of edema and inflammation determines the outcome of lung injury. Na/K-ATPase activity is responsible for edema clearance. This enzyme works as a cell receptor that triggers activation of mitogen-activated protein kinase (MAPK) intracellular signaling pathway. Therefore, injection of GLP into lungs induces injury by triggering inflammation.Methods
We injected GLP and ouabain, into mice lungs and compared their effects. Bronchoalveolar lavage fluid (BALF) was collected for cell and lipid body counting and measurement of protein and lipid mediators (PGE2 and LTB4). The levels of the IL-6, TNFα, IL-1B and MIP-1α were also quantified. Lung images illustrate the injury and whole-body plethysmography was performed to assay lung function. We used Toll-like receptor 4 (TLR4) knockout mice to evaluate leptospiral GLP-induced lung injury. Na/K-ATPase activity was determined in lung cells by nonradioactive rubidium incorporation. We analyzed MAPK p38 activation in lung and in epithelial and endothelial cells.Results
Leptospiral GLP and ouabain induced lung edema, cell migration and activation, production of lipid mediators and cytokines and hemorrhage. They induced lung function alterations and inhibited rubidium incorporation. Using TLR4 knockout mice, we showed that the GLP action was not dependent on TLR4 activation. GLP activated of p38 and enhanced cytokine production in cell cultures which was reversed by a selective p38 inhibitor.Conclusions
GLP and ouabain induced lung injury, as evidenced by increased lung inflammation and hemorrhage. To our knowledge, this is the first report showing GLP induces lung injury. GLP and ouabain are Na/K-ATPase targets, triggering intracellular signaling pathways. We showed p38 activation by GLP-induced lung injury, which was may be linked to Na/K-ATPase inhibition. Lung inflammation induced by GLP was not dependent on TLR4 activation. 相似文献19.
Prostaglandin E2 (PGE2) is induced in vivo by bacterial products including TLR agonists. To determine whether PGE2 is induced directly or via IL-1β, human monocytes and macrophages were cultured with LPS or with Pam3CSK4 in presence of caspase-1 inhibitor, ZVAD, or IL-1R antagonist, Kineret. TLR agonists induced PGE2 in macrophages exclusively via IL-1β-independent mechanisms. In contrast, ZVAD and Kineret reduced PGE2 production in LPS-treated (but not in Pam3CSK4-treated) monocytes, by 30–60%. Recombinant human IL-1β augmented COX-2 and mPGES-1 mRNA and PGE2 production in LPS-pretreated monocytes but not in un-primed or Pam3CSK4-primed monocytes. This difference was explained by the finding that LPS but not Pam3CSK4 induced phosphorylation of IRF3 in monocytes suggesting activation of the TRIF signaling pathway. Knocking down TRIF, TRAM, or IRF3 genes by siRNA inhibited IL-1β-induced COX-2 and mPGES-1 mRNA. Blocking of TLR4 endocytosis during LPS priming prevented the increase in PGE2 production by exogenous IL-1β. Our data showed that TLR2 agonists induce PGE2 in monocytes independently from IL-1β. In the case of TLR4, IL-1β augments PGE2 production in LPS-primed monocytes (but not in macrophages) through a mechanism that requires TLR4 internalization and activation of the TRIF/IRF3 pathway. These findings suggest a key role for blood monocytes in the rapid onset of fever in animals and humans exposed to bacterial products and some novel adjuvants. 相似文献