scholarly journals Francisella tularensis Invasion of Lung Epithelial Cells

2008 ◽  
Vol 76 (7) ◽  
pp. 2833-2842 ◽  
Author(s):  
Robin R. Craven ◽  
Joshua D. Hall ◽  
James R. Fuller ◽  
Sharon Taft-Benz ◽  
Thomas H. Kawula
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Francisella Tularensis ◽  
Bacterial Pathogen ◽  
Alveolar Epithelial Cells ◽  
Lung Epithelial Cells ◽  
Mouse Lung ◽  
Epithelial Cell Line ◽  
Bacterial Surface ◽  
Lung Epithelial

ABSTRACT Francisella tularensis, a gram-negative facultative intracellular bacterial pathogen, causes disseminating infections in humans and other mammalian hosts. Macrophages and other monocytes have long been considered the primary site of F. tularensis replication in infected animals. However, recently it was reported that F. tularensis also invades and replicates within alveolar epithelial cells following inhalation in a mouse model of tularemia. TC-1 cells, a mouse lung epithelial cell line, were used to study the process of F. tularensis invasion and intracellular trafficking within nonphagocytic cells. Live and paraformaldehyde-fixed F. tularensis live vaccine strain organisms associated with, and were internalized by, TC-1 cells at similar frequencies and with indistinguishable differences in kinetics. Inhibitors of microfilament and microtubule activity resulted in significantly decreased F. tularensis invasion, as did inhibitors of phosphatidylinositol 3-kinase and tyrosine kinase activity. Collectively, these results suggest that F. tularensis epithelial cell invasion is mediated by a preformed ligand on the bacterial surface and driven entirely by host cell processes. Once internalized, F. tularensis-containing endosomes associated with early endosome antigen 1 (EEA1) followed by lysosome-associated membrane protein 1 (LAMP-1), with peak coassociation frequencies occurring at 30 and 120 min postinoculation, respectively. By 2 h postinoculation, 70.0% (± 5.5%) of intracellular bacteria were accessible to antibody delivered to the cytoplasm, indicating vacuolar breakdown and escape into the cytoplasm.

The lack of attachment of transformed embryonic lung epithelial cells to collagen I is corrected by fibronectin and FXIII

1986 ◽  
Vol 86 (1) ◽  
pp. 95-107
Author(s):  
M. Paye ◽  
C.M. Lapiere
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Cell Line ◽  
Lung Epithelial Cells ◽  
Collagen I ◽  
Epithelial Cell Line ◽  
Embryonic Lung ◽  
Lung Epithelial ◽  
Minimal Concentration ◽  
Pulmonary Epithelial Cell

PER cells, a transformed pulmonary epithelial cell line that adhered to a large extent to a fibronectin substratum, were found to be attachment-deficient to collagen I. Although fibronectin can bind to collagen I monomers and polymers, the addition of exogenous fibronectin in the attachment medium induced the adhesion of these cells to collagen I polymers but not to monomers. By adding the transglutaminase of blood coagulation, FXIII, in the presence of fibronectin, the attachment of PER cells to collagen I monomers could be recovered while the minimal concentration of fibronectin needed to promote their adhesion to polymers was lowered. These studies indicate that FXIII enhances the fibronectin-mediated attachment of PER cells to collagen I.

scholarly journals Glycyrrhizin suppresses epithelial-mesenchymal transition by inhibiting high-mobility group box1 via the TGF-β1/Smad2/3 pathway in lung epithelial cells

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8514 ◽  
Author(s):  
Yanni Gui ◽  
Jian Sun ◽  
Wenjie You ◽  
Yuanhui Wei ◽  
Han Tian ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Cell Line ◽  
Epithelial Mesenchymal Transition ◽  
High Mobility ◽  
Lung Epithelial Cells ◽  
Epithelial Cell Line ◽  
Mesenchymal Transition ◽  
Lung Epithelial ◽  
Hmgb1 Expression

Background Epithelial-mesenchymal transition (EMT) plays an important role in fibrosis, chronic inflammation, tumor metastasis, etc. Glycyrrhizin, an active component extracted from licorice plant, has been reported to treat a variety of inflammatory reactions through inhibiting high-mobility group box1 (HMGB1), which has been suggested to be a significant mediator in EMT process. However, whether glycyrrhizin affects the EMT process or not remains unclear. Methods Human alveolar epithelial cell line A549 and normal human bronchial epithelial cell line BEAS-2B were treated with extrinsic TGF-β1 to induce EMT. Elisa was used to detect HMGB1 concentrations in cell supernatant. RNA interference and lentivirus infection experiments were performed to investigate the involvement of HMGB1 in EMT process. Cell Counting Kit-8 (CCK-8) was used to detect the viability of A549 and BEAS-2B cells treated with glycyrrhizin. Finally, the effects of glycyrrhizin on EMT changes, as well as the underlying mechanisms, were evaluated via Western blot, immunofluorescence and transwell assays. Results Our results showed that HMGB1 expression was increased by TGF-β1, and knockdown of HMGB1 expression reversed TGF-β1-induced EMT in A549 and BEAS-2B cells. Ectopic HMGB1 expression or TGF-β1 treatment caused a significant increase in HMGB1 release. Notably, we found that glycyrrhizin treatment effectively suppressed TGF-β1-induced EMT process by inhibiting HMGB1. Also, glycyrrhizin significantly inhibited the migration of both A549 and BEAS-2B cells promoted by TGF-β1. Mechanistically, HMGB1 overexpression could activate Smad2/3 signaling in A549 and BEAS-2B cells. Glycyrrhizin significantly blocked the phosphorylation of Smad2/3 stimulated either by TGF-β1 or by ectopic HMGB1 in A549 and BEAS-2B cells. Conclusions HMGB1 is a vital mediator of EMT changes induced by TGF-β1 in lung epithelial cells. Importantly, glycyrrhizin can effectively block Smad2/3 signaling pathway through inhibiting HMGB1, thereby suppressing the EMT progress.

Bioassay of a tracheal smooth muscle-constricting factor released by respiratory epithelial cells

1992 ◽  
Vol 263 (1) ◽  
pp. L137-L141 ◽  
Author(s):  
J. H. Wilkens ◽  
A. Becker ◽  
H. Wilkens ◽  
M. Emura ◽  
M. Riebe-Imre ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Muscle Tone ◽  
Lung Epithelial Cells ◽  
Epithelial Cell Line ◽  
Cell Column ◽  
Respiratory Epithelial Cells ◽  
Lung Epithelial ◽  
Respiratory Epithelial

Epithelium-derived factors of unknown identity have been proposed to modulate airway smooth muscle tone. We developed a novel sensitive bioassay system that allows serial perfusion of cultured respiratory epithelial cells and guinea pig trachea (GPT). GPT responses were assessed as diameter changes by computerized video microscopy (resolution, 15 microns). A permanent hamster lung epithelial cell line was grown on microcarrier beads and perfused in a cell column. When the outflow tubing from the epithelial cell column was connected to the inflow cannula, the detector GPT contracted, reaching 28 +/- 6% of the maximum methacholine (100 microM)-induced contraction (n = 12, P less than 0.001). Perfusion of the cell column with diclofenac (10 microM) or lysin-mono-acetylsalicylic acid (100 microM) abolished the GPT contraction, whereas selective perfusion of the detector GPT with either agent did not block the contraction. Analysis of the effluent of the epithelial cell column demonstrated a significant basal release of prostaglandins F2 alpha and E2 (PGF2 alpha and PGE2) and 6-ketoprostaglandin F1 alpha, whereas only marginal amounts of thromboxane B2 were detected. When given exogenously, PGF2 alpha, PGE2, PGI2, and U-46619 all contracted the GPT. It is concluded that lung epithelial cells can contract GPT by releasing a transferable factor. This factor is likely to be a constrictor cyclooxygenase product that is not produced in epithelium-denuded GPT.

PAR-2 activation and LPS synergistically enhance inflammatory signaling in airway epithelial cells by raising PAR expression level and interleukin-8 release

2007 ◽  
Vol 293 (5) ◽  
pp. L1208-L1218 ◽  
Author(s):  
Ewa Ostrowska ◽  
Elena Sokolova ◽  
Georg Reiser
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Airway Epithelial Cells ◽  
Lung Epithelial Cells ◽  
Expression Level ◽  
Epithelial Cell Line ◽  
Airway Epithelial ◽  
Protease Activated Receptors ◽  
Lung Epithelial ◽  
Epithelial Cell Lines

Protease-activated receptors (PARs) are involved in the contribution of airway epithelial cells to the development of inflammation by release of pro- and anti-inflammatory mediators. Here, we evaluated in epithelial cells the influence of LPS and continuous PAR activation on PAR expression level and the release of the proinflammatory chemokine IL-8. We studied primary human small airway epithelial cells and two airway epithelial cell lines, A549 and HBE cells. LPS specifically upregulated expression of PAR-2 but not of PAR-1. Exposure of epithelial cells to PAR-1 or PAR-2 agonists increased the PAR-1 expression level. The PAR-2 agonist exhibited higher potency than PAR-1 activators. However, the combined exposure of epithelial cells to LPS and PAR agonists abrogated the PAR-1 upregulation. The PAR-2 expression level was also upregulated after exposure to PAR-1 or PAR-2 agonists. This elevation was higher than the effect of PAR agonists on the PAR-1 level. In contrast to the PAR-1 level, the PAR-2 level remained elevated under concomitant stimulation with LPS and PAR-2 agonist. Furthermore, activation of PAR-2, but not of PAR-1, caused production of IL-8 from the epithelial cells. Interestingly, both in the epithelial cell line and in primary epithelial cells, there was a potentiation of the stimulation of the IL-8 synthesis and release by PAR-2 agonist together with LPS. In summary, these results underline the important role of PAR-2 in human lung epithelial cells. Moreover, our study shows an intricate interplay between LPS and PAR agonists in affecting PAR regulation and IL-8 production.

scholarly journals Sp3 regulates Fas expression in lung epithelial cells

1998 ◽  
Vol 333 (1) ◽  
pp. 209-213 ◽  
Author(s):  
Huiling PANG ◽  
Kathleen MIRANDA ◽  
Alan FINE
Keyword(s):  
Epithelial Cells ◽  
Promoter Activity ◽  
Functional Results ◽  
Lung Epithelial Cells ◽  
Site Directed Mutagenesis ◽  
Mouse Lung ◽  
Epithelial Cell Line ◽  
Upstream Sequence ◽  
Mobility Shift ◽  
Lung Epithelial

By transducing an apoptotic signal in immune effector cells, Fas has been directly implicated in the control of immunological activity. Expression and functional results, however, have also suggested a role for Fas in regulating cell turnover in specific epithelial populations. To characterize factors responsible for Fas expression in epithelial cells, approximately 3 kb of the 5´ flanking region of the mouse Fas gene was isolated. By rapid amplification of cDNA ends and primer extension, transcriptional start sites were identified within 50 bp upstream of the translation start site. Transient transfection of promoter–luciferase constructs in a mouse lung epithelial cell line, MLE-15, localized promoter activity to the first 77 bp of upstream sequence. By using a 60 bp DNA probe (-18 to -77) in electrophoretic mobility-shift assays, three shifted complexes were found. Incubation with excess cold Sp1 oligonucleotide or an anti-Sp3 antibody inhibited complex formation. Site-directed mutagenesis of the Sp1 site resulted in 60–70% loss of promoter activity. In Drosophila SL-2 cells, promoter activity was markedly increased by co-transfection of an Sp3 expression construct. These results show that the Sp3 protein is involved in regulating Fas gene expression in lung epithelial cells.

scholarly journals Regulation of IL-33 by Oncostatin M in Mouse Lung Epithelial Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Carl D. Richards ◽  
Laura Izakelian ◽  
Anisha Dubey ◽  
Grace Zhang ◽  
Steven Wong ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Alveolar Epithelial Cells ◽  
Lung Epithelial Cells ◽  
Oncostatin M ◽  
Mouse Lung ◽  
Nuclear Staining ◽  
Potent Inducer ◽  
Alveolar Epithelial ◽  
Lung Epithelial

IL-33 modulates both innate and adaptive immune responses at tissue sites including lung and may play critical roles in inflammatory lung disease. Although IL-33 expression can be altered upon NF-Kappa B activation, here we examine regulation by Oncostatin M, a gp130 cytokine family member, in mouse lung tissue. Responses were assessed in BALB/c mouse lung at day 7 of transient overexpression using endotracheally administered adenovirus encoding OSM (AdOSM) or empty vector (AdDel70). Whole lung extracts showed induction of IL-33 mRNA (>20-fold) and protein (10-fold increase in immunoblots) by AdOSM relative to AdDel70. Immunohistochemistry for IL-33 indicated a marked induction of nuclear staining in alveolar epithelial cellsin vivo. Oncostatin M stimulated IL-33 mRNA and IL-33 full length protein in C10 mouse type 2 alveolar epithelial cells in culture in time-dependent and dose-dependent fashion, whereas IL-6, LIF, IL-31, IL-4, or IL-13 did not, and TGFβrepressed IL-33. IL-33 induction was associated with activation of STAT3, and pharmacological inhibition of STAT3 ameliorated IL-33 levels. These results indicate Oncostatin M as a potent inducer of IL-33 in mouse lung epithelial cells and suggest that an OSM/IL-33 axis may participate in innate immunity and inflammatory conditions in lung.

scholarly journals PKCδ/midkine pathway drives hypoxia-induced proliferation and differentiation of human lung epithelial cells

2014 ◽  
Vol 306 (7) ◽  
pp. C648-C658 ◽  
Author(s):  
Hanying Zhang ◽  
Miyako Okamoto ◽  
Evgeniy Panzhinskiy ◽  
W. Michael Zawada ◽  
Mita Das
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Lung Diseases ◽  
Human Lung ◽  
Culture Media ◽  
Alveolar Epithelial Cells ◽  
Lung Epithelial Cells ◽  
Lung Epithelial ◽  
Proliferation And Differentiation ◽  
Human Lung Epithelial Cells

Epithelial cells are key players in the pathobiology of numerous hypoxia-induced lung diseases. The mechanisms mediating such hypoxic responses of epithelial cells are not well characterized. Earlier studies reported that hypoxia stimulates protein kinase C (PKC)δ activation in renal cancer cells and an increase in expression of a heparin-binding growth factor, midkine (MK), in lung alveolar epithelial cells. We reasoned that hypoxia might regulate MK levels via a PKCδ-dependent pathway and hypothesized that PKCδ-driven MK expression is required for hypoxia-induced lung epithelial cell proliferation and differentiation. Replication of human lung epithelial cells (A549) was significantly increased by chronic hypoxia (1% O2) and was dependent on expression of PKCδ. Hypoxia-induced proliferation of epithelial cells was accompanied by translocation of PKCδ from Golgi into the nuclei. Marked attenuation in MK protein levels by rottlerin, a pharmacological antagonist of PKC, and by small interfering RNA-targeting PKCδ, revealed that PKCδ is required for MK expression in both normoxic and hypoxic lung epithelial cells. Sequestering MK secreted into the culture media with a neutralizing antibody reduced hypoxia-induced proliferation demonstrating that an increase in MK release from cells is linked with epithelial cell division under hypoxia. In addition, recombinant MK accelerated transition of hypoxic epithelial cells to cells of mesenchymal phenotype characterized by elongated morphology and increased expression of mesenchymal markers, α-smooth muscle actin, and vimentin. We conclude that PKCδ/MK axis mediates hypoxic proliferation and differentiation of lung epithelial cells. Manipulation of PKCδ and MK activity in epithelial cells might be beneficial for the treatment of hypoxia-mediated lung diseases.

Cis-acting lnc-Cxcl2 restrains neutrophil-mediated lung inflammation by inhibiting epithelial cell CXCL2 expression in virus infection

2021 ◽  
Vol 118 (41) ◽  
pp. e2108276118
Author(s):  
Shuo Liu ◽  
Jiaqi Liu ◽  
Xue Yang ◽  
Minghong Jiang ◽  
Qingqing Wang ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Virus Infection ◽  
Viral Infection ◽  
Rna Binding ◽  
Influenza Virus Infection ◽  
Lung Epithelial Cells ◽  
Mouse Lung ◽  
Chemokine Production ◽  
Lung Epithelial

Chemokine production by epithelial cells is important for neutrophil recruitment during viral infection, the appropriate regulation of which is critical for restraining inflammation and attenuating subsequent tissue damage. Epithelial cell expression of long noncoding RNAs (lncRNAs), RNA-binding proteins, and their functional interactions during viral infection and inflammation remain to be fully understood. Here, we identified an inducible lncRNA in the Cxcl2 gene locus, lnc-Cxcl2, which could selectively inhibit Cxcl2 expression in mouse lung epithelial cells but not in macrophages. lnc-Cxcl2–deficient mice exhibited increased Cxcl2 expression, enhanced neutrophils recruitment, and more severe inflammation in the lung after influenza virus infection. Mechanistically, nucleus-localized lnc-Cxcl2 bound to Cxcl2 promoter, recruited a ribonucleoprotein La, which inhibited the chromatin accessibility of chemokine promoters, and consequently inhibited Cxcl2 transcription in cis. However, unlike mouse lnc-Cxcl2, human lnc-CXCL2-4-1 inhibited multiple immune cytokine expressions including chemokines in human lung epithelial cells. Together, our results demonstrate a self-protecting mechanism within epithelial cells to restrain chemokine and neutrophil-mediated inflammation, providing clues for better understanding chemokine regulation and epithelial cell function in lung viral infection.

scholarly journals The Severe Acute Respiratory Syndrome Coronavirus 3a Protein Up-Regulates Expression of Fibrinogen in Lung Epithelial Cells

2005 ◽  
Vol 79 (15) ◽  
pp. 10083-10087 ◽  
Author(s):  
Yee-Joo Tan ◽  
Puay-Yoke Tham ◽  
Daphne Z. L. Chan ◽  
Chih-Fong Chou ◽  
Shuo Shen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Severe Acute Respiratory Syndrome ◽  
Cell Line ◽  
Pulmonary Complications ◽  
Lung Epithelial Cells ◽  
Epithelial Cell Line ◽  
Mrna Levels ◽  
Lung Epithelial

ABSTRACT Here we analyzed the gene expression profile of cells that stably express the severe acute respiratory syndrome coronavirus (SARS-CoV) 3a protein to determine its effects on host functions. A lung epithelial cell-line, A549, was chosen for this study because the lung is the primary organ infected by SARS-CoV and fatalities resulted mainly from pulmonary complications. Our results showed that the expression of 3a up-regulates the mRNA levels of all three subunits, Aα, Bβ, and γ, of fibrinogen. Consequently, the intracellular levels as well as the secretion of fibrinogen were increased. We also observed increased fibrinogen levels in SARS-CoV-infected Vero E6 cells.

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