scholarly journals Paracoccidioides brasiliensis downmodulates α3 integrin levels in human lung epithelial cells in a TLR2-dependent manner

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bianca Carla Silva Campitelli de Barros ◽  
Bruna Rocha Almeida ◽  
Erika Suzuki
Keyword(s):  
Epithelial Cells ◽  
Host Cell ◽  
Paracoccidioides Brasiliensis ◽  
Cell Signalling ◽  
Lung Epithelial Cells ◽  
Host Cells ◽  
Signalling Pathways ◽  
Dependent Manner ◽  
Lung Epithelial ◽  
Α3 Integrin

Abstract Paracoccidioidomycosis (PCM) is the most prevalent systemic mycosis in Latin America and may be caused by the species Paracoccidioides brasiliensis. In the lungs, this fungus interacts with epithelial cells, activating host cell signalling pathways, resulting in the production of inflammatory mediators. This event may be initiated through the activation of Pattern-Recognition Receptors such as Toll-like Receptors (TLRs). By interacting with cell wall components, TLR2 is frequently related to fungal infections. In this work, we show that, after 24 h post-infection with P. brasiliensis, A549 lung epithelial cells presented higher TLR2 levels, which is important for IL-8 secretion. Besides, integrins may also participate in pathogen recognition by host cells. We verified that P. brasiliensis increased α3 integrin levels in A549 cells after 5 h of infection and promoted interaction between this receptor and TLR2. However, after 24 h, surprisingly, we verified a decrease of α3 integrin levels, which was dependent on direct contact between fungi and epithelial cells. Likewise, we observed that TLR2 is important to downmodulate α3 integrin levels after 24 h of infection. Thus, P. brasiliensis can modulate the host inflammatory response by exploiting host cell receptors and cell signalling pathways.

scholarly journals 969. GRP78 and Integrin β1/α3 Play Disparate Roles in Epithelium Invasion During Mucormycosis

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S37-S37
Author(s):  
Abdullah Alqarihi ◽  
Teclegiorgis Gebremariam ◽  
Sondus Alkhazraji ◽  
Priya Uppuluri ◽  
John E Edwards ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Host Cell ◽  
Cell Injury ◽  
Lung Epithelial Cells ◽  
Host Cells ◽  
Β1 Integrin ◽  
Dependent Manner ◽  
Cell Receptors ◽  
Lung Epithelial

Abstract Background Mucormycosis is a lethal fungal infection caused by Mucorales. Inhalation is the major route of entry resulting in rhino-orbital or pulmonary infections. Nasal and lung epithelial cells are among the first cells that encounter inhaled spores. We sought to identify the nasal and lung epithelial cell receptors interacting with Rhizopus during tissue invasion. Methods R. delemar-induced nasal (CCL30) or lung epithelial (A549) cell invasion was studied using Uvetix dye, while host cell injury was determined by 51Cr-release assay. Epithelial cell receptors were isolated by affinity purification of biotinylated host cell membrane proteins and then identified by LC-MS. Blocking antibodies were used to confirm the role of the receptor in the invasion/injury assays. For survival studies, ICR mice were immunosuppressed with cyclophosphamide and cortisone acetate on day-2, +3, and +8. Mice were infected with 2.5 × 105R. delemar spores intratracheally, and then treated with a single dose of 100 μg (i.p.) anti-β1 integrin antibody. Placebo mice received 100 µg of isotype-matching IgG. Results R. delemar invades and damages both cells in a time-dependent manner. Nasal Grp78 and alveolar β1α3 integrin were isolated as putative receptors. Polyclonal antibodies targeting Grp78 or β1 integrin blocked R. delemar-mediated endocytosis of nasal and lung cells by ~70%. Also, anti-Grp78 and anti-β1 integrin antibodies blocked R. delemar-induced nasal and lung cell injury by ~60% (P < 0.001). Elevated glucose, iron, or BHB increased the expression of nasal Grp78 by 2- to 6-fold which resulted in enhanced R. delemar-mediated invasion and injury of host cells, while having no effect on β1α3 integrin expression. Finally, β1 antibodies protected mice from mucormycosis with median survival time of 16 days for treated mice versus 11 days for placebo and an overall survival of 30% versus 0% for placebo mice (P = 0.0006). Conclusion The upregulation of Grp78 on nasal epithelial cells in response to physiological elevated concentrations of glucose, iron, and BHB and subsequent enhanced invasion likely to provide insights into why diabetics in ketoacidosis are infected with the rhino-orbital mucormycosis rather than pulmonary disease. Our studies also provide a foundation for therapeutic interventions against mucormycosis. Disclosures All authors: No reported disclosures.

scholarly journals Host DNA Repair Proteins in Response toPseudomonas aeruginosain Lung Epithelial Cells and in Mice

2010 ◽  
Vol 79 (1) ◽  
pp. 75-87 ◽  
Author(s):  
Min Wu ◽  
Huang Huang ◽  
Weidong Zhang ◽  
Shibichakravarthy Kannan ◽  
Andrew Weaver ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Epithelial Cells ◽  
Critical Role ◽  
Lung Epithelial Cells ◽  
Host Cells ◽  
Myeloperoxidase Activity ◽  
Gram Negative ◽  
Lung Epithelial ◽  
Dna Repair Proteins

ABSTRACTAlthough DNA repair proteins in bacteria are critical for pathogens' genome stability and for subverting the host defense, the role of host DNA repair proteins in response to bacterial infection is poorly defined. Here, we demonstrate, for the first time, that infection with the Gram-negative bacteriumPseudomonas aeruginosasignificantly altered the expression and enzymatic activity of 8-oxoguanine DNA glycosylase (OGG1) in lung epithelial cells. Downregulation of OGG1 by a small interfering RNA strategy resulted in severe DNA damage and cell death. In addition, acetylation of OGG1 is required for host responses to bacterial genotoxicity, as mutations of OGG1 acetylation sites increased Cockayne syndrome group B (CSB) protein expression. These results also indicate that CSB may be involved in DNA repair activity during infection. Furthermore, OGG1 knockout mice exhibited increased lung injury after infection withP. aeruginosa, as demonstrated by higher myeloperoxidase activity and lipid peroxidation. Together, our studies indicate thatP. aeruginosainfection induces significant DNA damage in host cells and that DNA repair proteins play a critical role in the host response toP. aeruginosainfection, serving as promising targets for the treatment of this condition and perhaps more broadly Gram-negative bacterial infections.

scholarly journals Cytotoxic Effects of Air Freshener Biocides in Lung Epithelial Cells

2013 ◽  
Vol 8 (9) ◽  
pp. 1934578X1300800
Author(s):  
Jung-Taek Kwon ◽  
Mimi Lee ◽  
Gun-Baek Seo ◽  
Hyun-Mi Kim ◽  
Ilseob Shim ◽  
...  
Keyword(s):  
Dna Damage ◽  
Epithelial Cells ◽  
Cell Viability ◽  
Lung Epithelial Cells ◽  
Ros Generation ◽  
Dependent Manner ◽  
Cytotoxic Effects ◽  
Lung Epithelial ◽  
Dose Dependent ◽  
A549 Lung

This study evaluated the cytotoxicity of mixtures of citral (CTR) and either benzisothiazolinone (BIT, Mix-CTR-BIT) or triclosan (TCS, Mix-CTR-TCS) in human A549 lung epithelial cells. We investigated the effects of various mix ratios of these common air freshener ingredients on cell viability, cell proliferation, reactive oxygen species (ROS) generation, and DNA damage. Mix-CTR-BIT and Mix-CTR-TCS significantly decreased the viability of lung epithelial cells and inhibited cell growth in a dose-dependent manner. In addition, both mixtures increased ROS generation, compared to that observed in control cells. In particular, cell viability, growth, and morphology were affected upon increase in the proportion of BIT or TCS in the mixture. However, comet analysis showed that treatment of cells with Mix-CTR-BIT or Mix-CTR-TCS did not increase DNA damage. Taken together, these data suggested that increasing the content of biocides in air fresheners might induce cytotoxicity, and that screening these compounds using lung epithelial cells may contribute to hazard assessment.

scholarly journals Inhibition of acute lethal pulmonary inflammation by the IDO–AhR pathway

2017 ◽  
Vol 114 (29) ◽  
pp. E5881-E5890 ◽  
Author(s):  
Soung-Min Lee ◽  
Ha Young Park ◽  
Young-Sill Suh ◽  
Eun Hye Yoon ◽  
Juyang Kim ◽  
...  
Keyword(s):  
T Cells ◽  
Epithelial Cells ◽  
Pulmonary Inflammation ◽  
Lung Parenchyma ◽  
Lung Epithelial Cells ◽  
Dependent Manner ◽  
Independent Manner ◽  
Hematopoietic Stem ◽  
Lung Epithelial ◽  
Ifn Γ

The lung is a prototypic organ that was evolved to reduce immunopathology during the immune response to potentially hazardous endogenous and exogenous antigens. In this study, we show that donor CD4+ T cells transiently induced expression of indoleamine 2,3-dioxygenase (IDO) in lung parenchyma in an IFN-γ–dependent manner early after allogeneic hematopoietic stem cell transplantation (HSCT). Abrogation of host IDO expression by deletion of the IDO gene or the IFN-γ gene in donor T cells or by FK506 treatment resulted in acute lethal pulmonary inflammation known as idiopathic pneumonia syndrome (IPS). Interestingly, IL-6 strongly induced IDO expression in an IFN-γ–independent manner when deacetylation of STAT3 was inhibited. Accordingly, a histone deacetylase inhibitor (HDACi) could reduce IPS in the state where IFN-γ expression was suppressed by FK506. Finally, l-kynurenine produced by lung epithelial cells and alveolar macrophages during IPS progression suppresses the inflammatory activities of lung epithelial cells and CD4+ T cells through the aryl hydrocarbon receptor pathway. Taken together, our results reveal that IDO is a critical regulator of acute pulmonary inflammation and that regulation of IDO expression by HDACi may be a therapeutic approach for IPS after HSCT.

scholarly journals SARS-CoV-2 spike protein induces inflammation via TLR2-dependent activation of the NF-κB pathway

2021 ◽  
Author(s):  
Shahanshah Khan ◽  
Mahnoush S. Shafiei ◽  
Christopher Longoria ◽  
John Schoggins ◽  
Rashmin C. Savani ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Inflammatory Response ◽  
Inflammatory Cytokines ◽  
Lung Epithelial Cells ◽  
Dependent Manner ◽  
S Protein ◽  
Cytokines And Chemokines ◽  
Lung Epithelial ◽  
Mouse Macrophages ◽  
Human And Mouse

Pathogenesis of COVID-19 is associated with a hyperinflammatory response; however, the precise mechanism of SARS-CoV-2-induced inflammation is poorly understood. Here we investigated direct inflammatory functions of major structural proteins of SARS-CoV-2. We observed that spike (S) protein potently induces inflammatory cytokines and chemokines including IL-6, IL-1b, TNFa, CXCL1, CXCL2, and CCL2, but not IFNs in human and mouse macrophages. No such inflammatory response was observed in response to membrane (M), envelope (E), and neucleocapsid (N) proteins. When stimulated with extracellular S protein, human lung epithelial cells A549 also produce inflammatory cytokines and chemokines. Interestingly, epithelial cells expressing S protein intracellularly are non-inflammatory, but elicit an inflammatory response in macrophages when co-cultured. Biochemical studies revealed that S protein triggers inflammation via activation of the NF-kB pathway in a MyD88-dependent manner. Further, such an activation of the NF-kB pathway is abrogated in Tlr2-deficient macrophages. Consistently, administration of S protein induces IL-6, TNF-a, and IL-1b in wild-type, but not Tlr2-deficient mice. Together these data reveal a mechanism for the cytokine storm during SARS-CoV-2 infection and suggest that TLR2 could be a potential therapeutic target for COVID-19.

Urokinase induces its own expression in Beas2B lung epithelial cells

2002 ◽  
Vol 283 (2) ◽  
pp. L319-L328 ◽  
Author(s):  
Sreerama Shetty ◽  
Usha R. Pendurthi ◽  
Prathap Kumar Shetty Halady ◽  
Ali O. Azghani ◽  
Steven Idell
Keyword(s):  
Epithelial Cells ◽  
Tyrosine Kinase ◽  
Lung Inflammation ◽  
Cellular Proliferation ◽  
Kinase Inhibitor ◽  
Lung Epithelial Cells ◽  
Cell Surface Receptor ◽  
Dependent Manner ◽  
Amino Terminal ◽  
Lung Epithelial

The urokinase-type plasminogen activator (uPA) interacts with its receptor (uPAR) to promote local proteolysis as well as cellular proliferation and migration. These functions contribute to the pathogenesis of lung inflammation and remodeling as well as the growth and invasiveness of lung neoplasms. In this study, we sought to determine if uPA alters its own expression in lung epithelial cells. Using immunoprecipitation and Western and Northern blotting techniques, we found that uPA treatment enhanced uPA expression in Beas2B lung epithelial cells in a time- and concentration-dependent manner. The induction of uPA expression is mediated through its cell surface receptor uPAR and does not require uPA enzymatic activity. The amino-terminal fragment of uPA, lacking the catalytic domain, is sufficient to induce uPA expression. The serine protease plasmin and the protease inhibitor aprotinin failed to alter uPA-mediated uPA expression, whereas α-thrombin potentiated the response. Pretreatment of Beas2B cells with a tyrosine kinase inhibitor, herbimycin, suggests that activation of tyrosine kinase(s) is involved in the uPA-mediated uPA expression. Induction of uPA expression by exposure of lung-derived epithelial cells to uPA is a newly defined pathway by which this protease could influence expression of local fibrinolytic activity and other uPA-dependent cellular responses germane to lung inflammation or neoplasia.

scholarly journals Peroxisome Proliferator-Activated Receptors Mediate Host Cell Proinflammatory Responses to Pseudomonas aeruginosa Autoinducer

2008 ◽  
Vol 190 (13) ◽  
pp. 4408-4415 ◽  
Author(s):  
Aruna Jahoor ◽  
Rashila Patel ◽  
Amanda Bryan ◽  
Catherine Do ◽  
Jay Krier ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Epithelial Cells ◽  
Transcriptional Activity ◽  
Expression Patterns ◽  
Lung Epithelial Cells ◽  
Host Cells ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Pparγ Agonist ◽  
Lung Epithelial

ABSTRACT The pathogenic bacterium Pseudomonas aeruginosa utilizes the 3-oxododecanoyl homoserine lactone (3OC12-HSL) autoinducer as a signaling molecule to coordinate the expression of virulence genes through quorum sensing. 3OC12-HSL also affects responses in host cells, including the upregulation of genes encoding inflammatory cytokines. This proinflammatory response may exacerbate underlying disease during P. aeruginosa infections. The specific mechanism(s) through which 3OC12-HSL influences host responses is unclear, and no mammalian receptors for 3OC12-HSL have been identified to date. Here, we report that 3OC12-HSL increases mRNA levels for a common panel of proinflammatory genes in murine fibroblasts and human lung epithelial cells. To identify putative 3OC12-HSL receptors, we examined the expression patterns of a panel of nuclear hormone receptors in these two cell lines and determined that both peroxisome proliferator-activated receptor beta/delta (PPARβ/δ) and PPARγ were expressed. 3OC12-HSL functioned as an agonist of PPARβ/δ transcriptional activity and an antagonist of PPARγ transcriptional activity and inhibited the DNA binding ability of PPARγ. The proinflammatory effect of 3OC12-HSL in lung epithelial cells was blocked by the PPARγ agonist rosiglitazone, suggesting that 3OC12-HSL and rosiglitazone are mutually antagonistic negative and positive regulators of PPARγ activity, respectively. These data identify PPARβ/δ and PPARγ as putative mammalian 3OC12-HSL receptors and suggest that PPARγ agonists may be employed as anti-inflammatory therapeutics for P. aeruginosa infections.

scholarly journals Cytosolic phospholipase A2α activation induced by S1P is mediated by the S1P3 receptor in lung epithelial cells

2008 ◽  
Vol 295 (2) ◽  
pp. L326-L335 ◽  
Author(s):  
Li-Yuan Chen ◽  
Grzegorz Woszczek ◽  
Sahrudaya Nagineni ◽  
Carolea Logun ◽  
James H. Shelhamer
Keyword(s):  
Epithelial Cells ◽  
Rho Kinase ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Calcium Flux ◽  
Lipid Mediator ◽  
Dependent Manner ◽  
Cytosolic Phospholipase ◽  
Lung Epithelial ◽  
Sphingosine 1 Phosphate

Cytosolic phospholipase A2α (cPLA2α) activation is a regulatory step in the control of arachidonic acid (AA) liberation for eicosanoid formation. Sphingosine 1-phosphate (S1P) is a bioactive lipid mediator involved in the regulation of many important proinflammatory processes and has been found in the airways of asthmatic subjects. We investigated the mechanism of S1P-induced AA release and determined the involvement of cPLA2α in these events in A549 human lung epithelial cells. S1P induced AA release rapidly within 5 min in a dose- and time-dependent manner. S1P-induced AA release was inhibited by the cPLA2α inhibitors methyl arachidonyl fluorophosphonate (MAFP) and pyrrolidine derivative, by small interfering RNA-mediated downregulation of cPLA2α, and by inhibition of S1P-induced calcium flux, suggesting a significant role of cPLA2α in S1P-mediated AA release. Knockdown of the S1P3 receptor, the major S1P receptor expressed on A549 cells, inhibited S1P-induced calcium flux and AA release. The S1P-induced calcium flux and AA release was associated with sphingosine kinase 1 (Sphk1) expression and activity. Furthermore, Rho-associated kinase, downstream of S1P3, was crucial for S1P-induced cPLA2α activation. Our data suggest that S1P acting through S1P3, calcium flux, and Rho kinase activates cPLA2α and releases AA in lung epithelial cells. An understanding of S1P-induced cPLA2α activation mechanisms in epithelial cells may provide potential targets to control inflammatory processes in the lung.

scholarly journals Thrombin Induces NF-κB Activation and IL-8/CXCL8 Expression in Lung Epithelial Cells by a Rac1-dependent PI3K/Akt Pathway

2011 ◽  
Vol 286 (12) ◽  
pp. 10483-10494 ◽  
Author(s):  
Chien-Huang Lin ◽  
Hui-Wen Cheng ◽  
Hon-Ping Ma ◽  
Chih-Hsiung Wu ◽  
Chuang-Ye Hong ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Human Lung ◽  
Luciferase Activity ◽  
Lung Epithelial Cells ◽  
Akt Pathway ◽  
Dependent Manner ◽  
Akt Inhibitor ◽  
Iκb Kinase ◽  
Lung Epithelial ◽  
Human Lung Epithelial Cells

We previously showed that thrombin induces interleukin (IL)-8/CXCL8 expression via the protein kinase C (PKC)α/c-Src-dependent IκB kinase α/β (IKKα/β)/NF-κB signaling pathway in human lung epithelial cells. In this study, we further investigated the roles of Rac1, phosphoinositide 3-kinase (PI3K), and Akt in thrombin-induced NF-κB activation and IL-8/CXCL8 expression. Thrombin-induced IL-8/CXCL8 release and IL-8/CXCL8-luciferase activity were attenuated by a PI3K inhibitor (LY294002), an Akt inhibitor (1-l-6-hydroxymethyl-chiro-inositol-2-((R)-2-O-methyl-3-O-octadecylcarbonate)), and the dominant negative mutants of Rac1 (RacN17) and Akt (AktDN). Treatment of cells with thrombin caused activation of Rac and Akt. The thrombin-induced increase in Akt activation was inhibited by RacN17 and LY294002. Stimulation of cells with thrombin resulted in increases in IKKα/β activation and κB-luciferase activity; these effects were inhibited by RacN17, LY294002, an Akt inhibitor, and AktDN. Treatment of cells with thrombin induced Gβγ, p85α, and Rac1 complex formation in a time-dependent manner. These results imply that thrombin activates the Rac1/PI3K/Akt pathway through formation of the Gβγ, Rac1, and p85α complex to induce IKKα/β activation, NF-κB transactivation, and IL-8/CXCL8 expression in human lung epithelial cells.

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