scholarly journals Roles of Chaperone/Usher Pathways of Yersinia pestis in a Murine Model of Plague and Adhesion to Host Cells

2012 ◽  
Vol 80 (10) ◽  
pp. 3490-3500 ◽  
Author(s):  
Matthew Hatkoff ◽  
Lisa M. Runco ◽  
Celine Pujol ◽  
Indralatha Jayatilaka ◽  
Martha B. Furie ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Yersinia Pestis ◽  
Pathogenic Bacteria ◽  
Lung Epithelial Cells ◽  
Host Cells ◽  
Cell Binding ◽  
Content Type ◽  
Infection Models ◽  
Virulence Attenuation ◽  
Lung Epithelial

ABSTRACTYersinia pestisand many other Gram-negative pathogenic bacteria use the chaperone/usher (CU) pathway to assemble virulence-associated surface fibers termed pili or fimbriae.Y. pestishas two well-characterized CU pathways: thecafgenes coding for the F1 capsule and thepsagenes coding for the pH 6 antigen. TheY. pestisgenome contains additional CU pathways that are capable of assembling pilus fibers, but the roles of these pathways in the pathogenesis of plague are not understood. We constructed deletion mutations in the usher genes for six of the additionalY. pestisCU pathways. The wild-type (WT) and usher deletion strains were compared in the murine bubonic (subcutaneous) and pneumonic (intranasal) plague infection models.Y. pestisstrains containing deletions in CU pathwaysy0348-0352,y1858-1862, andy1869-1873were attenuated for virulence compared to the WT strain by the intranasal, but not subcutaneous, routes of infection, suggesting specific roles for these pathways during pneumonic plague. We examined binding of theY. pestisWT and usher deletion strains to A549 human lung epithelial cells, HEp-2 human cervical epithelial cells, and primary human and murine macrophages.Y. pestisCU pathwaysy0348-0352andy1858-1862were found to contribute to adhesion to all host cells tested, whereas pathwayy1869-1873was specific for binding to macrophages. The correlation between the virulence attenuation and host cell binding phenotypes of the usher deletion mutants identifies three of the additional CU pathways ofY. pestisas mediating interactions with host cells that are important for the pathogenesis of plague.

scholarly journals Pseudomonas Quinolone Signal Induces Oxidative Stress and Inhibits Heme Oxygenase-1 Expression in Lung Epithelial Cells

2017 ◽  
Vol 85 (9) ◽  
Author(s):  
Maher Y. Abdalla ◽  
Traci Hoke ◽  
Javier Seravalli ◽  
Barbara L. Switzer ◽  
Melissa Bavitz ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Flow Cytometry ◽  
Epithelial Cells ◽  
Heme Oxygenase ◽  
Lung Epithelial Cells ◽  
Host Cells ◽  
Heme Oxygenase 1 ◽  
Ros Production ◽  
Content Type ◽  
Lung Epithelial

ABSTRACT Pseudomonas aeruginosa causes lung infections in patients with cystic fibrosis (CF). The Pseudomonas quinolone signal (PQS) compound is a secreted P. aeruginosa virulence factor that contributes to the pathogenicity of P. aeruginosa. We were able to detect PQS in sputum samples from CF patients infected with P. aeruginosa but not in samples from uninfected patients. We then tested the hypothesis that PQS induces oxidative stress in host cells by determining the ability of PQS to induce the production of reactive oxygen species (ROS) in lung epithelial cells (A549 and primary normal human bronchial epithelial [NHBE]) cells and macrophages (J774A.1 and THP-1). ROS production induced by PQS was detected with fluorescent probes (dichlorodihydrofluorescein diacetate, dihydroethidium, and MitoSOX Red) in conjunction with confocal microscopy and flow cytometry. PQS induced ROS production in lung epithelial (A549 and NHBE) cells and macrophages (J774A.1 and THP-1 cells). NHBE cells were sensitive to PQS concentrations as low as 500 ng/ml. PQS significantly induced early apoptosis (P < 0.05, n = 6) in lung epithelial cells, as measured by annexin/propidium iodide detection by flow cytometry. However, no change in apoptosis upon PQS treatment was seen in J774A.1 cells. Heme oxygenase-1 (HO-1) protein is an antioxidant enzyme usually induced by oxidative stress. Interestingly, incubation with PQS significantly reduced HO-1 and NrF2 expression in A549 and NHBE cells but increased HO-1 expression in J774A.1 cells (P < 0.05, n = 3), as determined by immunoblotting and densitometry. These PQS effects on host cells could play an important role in the pathogenicity of P. aeruginosa infections.

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 Role of Lung Epithelial Cells in Defense against Klebsiella pneumoniae Pneumonia

2002 ◽  
Vol 70 (3) ◽  
pp. 1075-1080 ◽  
Author(s):  
Guadalupe Cortés ◽  
Dolores Álvarez ◽  
Carles Saus ◽  
Sebastián Albertí
Keyword(s):  
Epithelial Cells ◽  
Klebsiella Pneumoniae ◽  
Type Strain ◽  
Pathogenic Bacteria ◽  
Wild Type Strain ◽  
Capsular Polysaccharide ◽  
Defense Mechanism ◽  
Lung Epithelial Cells ◽  
Wild Type ◽  
Lung Epithelial

ABSTRACT The airway epithelium represents a primary site for the entry of pathogenic bacteria into the lungs. It has been suggested for many respiratory pathogens, including Klebsiella pneumoniae, that adhesion and invasion of the lung epithelial cells is an early stage of the pneumonia process. We observed that poorly encapsulated K. pneumoniae clinical isolates and an isogenic unencapsulated mutant invaded lung epithelial cells more efficiently than highly encapsulated strains independent of the K type. By contrast, the unencapsulated mutant was completely avirulent in a mouse model of pneumonia, unlike the wild-type strain, which produced pneumonia and systemic infection. Furthermore, the unencapsulated mutant bound more epithelially produced complement component C3 than the wild-type strain. Our results show that lung epithelial cells play a key role as a host defense mechanism against K. pneumoniae pneumonia, using two different strategies: (i) ingestion and control of the microorganisms and (ii) opsonization of the microorganisms. Capsular polysaccharide avoids both mechanisms and enhances the virulence of K. pneumoniae.

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 Linocin and OmpW Are Involved in Attachment of the Cystic Fibrosis-Associated Pathogen Burkholderia cepacia Complex to Lung Epithelial Cells and Protect Mice against Infection

2016 ◽  
Vol 84 (5) ◽  
pp. 1424-1437 ◽  
Author(s):  
Siobhán McClean ◽  
Marc E. Healy ◽  
Cassandra Collins ◽  
Stephen Carberry ◽  
Luke O'Shaughnessy ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Epithelial Cells ◽  
Burkholderia Cepacia ◽  
Therapeutic Option ◽  
Lung Epithelial Cells ◽  
Burkholderia Cenocepacia ◽  
Burkholderia Cepacia Complex ◽  
Content Type ◽  
Lung Epithelial ◽  
Proteomics Approach

Members of theBurkholderia cepaciacomplex (Bcc) cause chronic opportunistic lung infections in people with cystic fibrosis (CF), resulting in a gradual lung function decline and, ultimately, patient death. The Bcc is a complex of 20 species and is rarely eradicated once a patient is colonized; therefore, vaccination may represent a better therapeutic option. We developed a new proteomics approach to identify bacterial proteins that are involved in the attachment of Bcc bacteria to lung epithelial cells. Fourteen proteins were reproducibly identified by two-dimensional gel electrophoresis from four Bcc strains representative of two Bcc species:Burkholderia cenocepacia, the most virulent, andB. multivorans, the most frequently acquired. Seven proteins were identified in both species, but only two were common to all four strains, linocin and OmpW. Both proteins were selected based on previously reported data on these proteins in other species.Escherichia colistrains expressing recombinant linocin and OmpW showed enhanced attachment (4.2- and 3.9-fold) to lung cells compared to the control, confirming that both proteins are involved in host cell attachment. Immunoproteomic analysis using serum from Bcc-colonized CF patients confirmed that both proteins elicit potent humoral responsesin vivo. Mice immunized with either recombinant linocin or OmpW were protected fromB. cenocepaciaandB. multivoranschallenge. Both antigens induced potent antigen-specific antibody responses and stimulated strong cytokine responses. In conclusion, our approach identified adhesins that induced excellent protection against two Bcc species and are promising vaccine candidates for a multisubunit vaccine. Furthermore, this study highlights the potential of our proteomics approach to identify potent antigens against other difficult pathogens.

scholarly journals The Novel Fibrinogen-Binding Protein FbsB Promotes Streptococcus agalactiae Invasion into Epithelial Cells

2004 ◽  
Vol 72 (6) ◽  
pp. 3495-3504 ◽  
Author(s):  
Heike Gutekunst ◽  
Bernhard J. Eikmanns ◽  
Dieter J. Reinscheid
Keyword(s):  
Epithelial Cells ◽  
Streptococcus Agalactiae ◽  
Deletion Mutant ◽  
Binding Protein ◽  
Lung Epithelial Cells ◽  
Host Cells ◽  
Enzyme Linked Immunosorbent Assay ◽  
Bacterial Invasion ◽  
Fibrinogen Binding ◽  
Lung Epithelial

ABSTRACT Streptococcus agalactiae is a major cause of bacterial sepsis and meningitis in human newborns. The interaction of S. agalactiae with host proteins and the entry into host cells thereby represent important virulence traits of these bacteria. The present report describes the identification of the fbsB gene, encoding a novel fibrinogen-binding protein that plays a crucial role in the invasion of S. agalactiae into human cells. In Western blots and enzyme-linked immunosorbent assay (ELISA) experiments, the FbsB protein was demonstrated to interact with soluble and immobilized fibrinogen. Binding studies showed the N-terminal 388 residues of FbsB and the Aα-subunit of human fibrinogen to recognize each other. By reverse transcription (RT)-PCR, the fbsB gene was shown to be cotranscribed with the gbs0851 gene in S. agalactiae. Deletion of the fbsB gene in the genome of S. agalactiae did not influence the binding of the bacteria to fibrinogen, suggesting that FbsB does not participate in the attachment of S. agalactiae to fibrinogen. In tissue culture experiments, however, the fbsB deletion mutant was severely impaired in its invasion into lung epithelial cells. Bacterial invasion could be reestablished by introducing the fbsB gene on a shuttle plasmid into the fbsB deletion mutant. Furthermore, treatment of lung epithelial cells with FbsB fusion protein blocked S. agalactiae invasion of epithelial cells in a dose-dependent fashion. These results suggest an important role of the FbsB protein in the overall process of host cell entry by S. agalactiae.

scholarly journals Pneumocystis carinii Interactions with Lung Epithelial Cells and Matrix Proteins Induce Expression and Activity of the PcSte20 Kinase with Subsequent Phosphorylation of the Downstream Cell Wall Biosynthesis Kinase PcCbk1

2011 ◽  
Vol 79 (10) ◽  
pp. 4157-4164 ◽  
Author(s):  
Theodore J. Kottom ◽  
Joshua W. Burgess ◽  
Andrew H. Limper
Keyword(s):  
Cell Wall ◽  
Epithelial Cells ◽  
Fungal Pathogen ◽  
Pneumocystis Carinii ◽  
Specific Region ◽  
Lung Epithelial Cells ◽  
Matrix Proteins ◽  
Content Type ◽  
Lung Epithelial ◽  
Opportunistic Fungal Pathogen

ABSTRACTEukaryotic cell proliferation and phenotype are highly regulated by contact-dependent mechanisms. We have previously shown that the binding and interaction of the opportunistic fungal pathogenPneumocystis cariniito lung epithelial cells and extracellular matrix proteins induces mRNA expression of both the mitogen-activated protein (MAP) kinaseP. cariniiSte20 (PcSte20) and the cell wall-remodeling enzymePcCbk1(16). Herein, we report that in addition toPcSte20mRNA expression being upregulated,PneumocystisPcSte20 kinase activity is increased upon interacting with these same lung targets. This activity is also significantly suppressed byClostridium difficiletoxin B, a pan-specific inhibitor of small GTPases, demonstrating the potential role of a Cdc42-like molecule in this signaling cascade. We further observed that the PcSte20 kinase physically interacts with a specific region of theP. cariniicell wall biosynthesis kinase, PcCbk1, a downstream kinase important for mating projection formation and cell wall remodeling. This direct binding was mapped to a specific region of the PcCbk1 protein. We also demonstrated that PcSte20 obtained from wholeP. cariniilysates has the ability to phosphorylate PcCbk1 after the organism interacts with lung epithelial cells and extracellular matrix components. These observations provide new insights intoP. cariniisignaling induced by interactions of this important opportunistic fungal pathogen with lung epithelial cells and matrix.

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 &lt; 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 Lcl of Legionella pneumophila Is an Immunogenic GAG Binding Adhesin That Promotes Interactions with Lung Epithelial Cells and Plays a Crucial Role in Biofilm Formation

2011 ◽  
Vol 79 (6) ◽  
pp. 2168-2181 ◽  
Author(s):  
Carla Duncan ◽  
Akriti Prashar ◽  
Jannice So ◽  
Patrick Tang ◽  
Donald E. Low ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Legionella Pneumophila ◽  
Biofilm Formation ◽  
Case Fatality ◽  
Lung Epithelial Cells ◽  
Molecular Evidence ◽  
Heparin Binding ◽  
Content Type ◽  
Lung Epithelial

ABSTRACTLegionellosis is mostly caused byLegionella pneumophilaand is defined by a severe respiratory illness with a case fatality rate ranging from 5 to 80%.In vitroandin vivo, interactions ofL. pneumophilawith lung epithelial cells are mediated by the sulfated glycosaminoglycans (GAGs) of the host extracellular matrix. In this study, we have identified severalLegionellaheparin binding proteins. We have shown that one of these proteins, designated Lcl, is a polymorphic adhesin ofL. pneumophilathat is produced during legionellosis. Homologues of Lcl are ubiquitous inL. pneumophilaserogroups but are undetected in otherLegionellaspecies. Recombinant Lcl binds to GAGs, and a Δlpg2644mutant demonstrated reduced binding to GAGs and human lung epithelial cells. Importantly, we showed that the Δlpg2644strain is dramatically impaired in biofilm formation. These data delineate the role of Lcl in the GAG binding properties ofL. pneumophilaand provide molecular evidence regarding its role inL. pneumophilaadherence and biofilm formation.

scholarly journals Stenotrophomonas maltophiliaEncodes a VirB/VirD4 Type IV Secretion System That Modulates Apoptosis in Human Cells and Promotes Competition against Heterologous Bacteria, IncludingPseudomonas aeruginosa

2019 ◽  
Vol 87 (9) ◽  
Author(s):  
Megan Y. Nas ◽  
Richard C. White ◽  
Ashley L. DuMont ◽  
Alberto E. Lopez ◽  
Nicholas P. Cianciotto
Keyword(s):  
Epithelial Cells ◽  
Mammalian Cells ◽  
Secretion System ◽  
Lung Epithelial Cells ◽  
Type Ii Secretion ◽  
Bacterial Cells ◽  
Content Type ◽  
Type Iv ◽  
Lung Epithelial ◽  
Induced Apoptosis

ABSTRACTStenotrophomonas maltophiliais an emerging opportunistic and nosocomial pathogen.S. maltophiliais also a risk factor for lung exacerbations in cystic fibrosis patients.S. maltophiliaattaches to various mammalian cells, and we recently documented that the bacterium encodes a type II secretion system which triggers detachment-induced apoptosis in lung epithelial cells. We have now confirmed thatS. maltophiliaalso encodes a type IVA secretion system (VirB/VirD4 [VirB/D4] T4SS) that is highly conserved amongS. maltophiliastrains and, looking beyond theStenotrophomonasgenus, is most similar to the T4SS ofXanthomonas. To define the role(s) of this T4SS, we constructed a mutant of strain K279a that is devoid of secretion activity due to loss of the VirB10 component. The mutant induced a higher level of apoptosis upon infection of human lung epithelial cells, indicating that a T4SS effector(s) has antiapoptotic activity. However, when we infected human macrophages, the mutant triggered a lower level of apoptosis, implying that the T4SS also elaborates a proapoptotic factor(s). Moreover, when we cocultured K279a with strains ofPseudomonas aeruginosa, the T4SS promoted the growth ofS. maltophiliaand reduced the numbers of heterologous bacteria, signaling that another effector(s) has antibacterial activity. In all cases, the effect of the T4SS requiredS. maltophiliacontact with its target. Thus,S. maltophiliaVirB/D4 T4SS appears to secrete multiple effectors capable of modulating death pathways. That a T4SS can have anti- and prokilling effects on different targets, including both human and bacterial cells, has, to our knowledge, not been seen before.

Sign in / Sign up

Export Citation Format

Share Document