Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Transcription profiling of human A549 pneumocyte cells infected with wild type and type III secretion system mutants of Pseudomonas aeruginosa

ABSTRACT: The bacterial type III secretion system (TTSS) is dedicated to directly effect host cell pathways by pathogens. In order to identify the key host responses of the various parts of the TTSS, we utilized expression profiling of a lung pneumocytes cell line, A549, exposed to various isogenic mutant strains of Pseudomonas aeruginosa PAK. We have devised a novel filtering method to isolate the key responses to the effector proteins as well as the translocation machinery. Individually, the effector proteins elicited host responses that were consistent with the known function of each, many of which either regulated, or are regulated by the cell cycle. However, our analysis has shown that the effector proteins elicit a distinct host expression pattern when present in combination, suggesting that these proteins function in synergy. Furthermore, the host transcriptional response to the translocation complex involved genes that are involved in remodeling of the plasma membrane, suggesting that the host cell is able to sense the protrusion of the TTSS machinery. This study shows that the individual components of the TTSS define an integrated system and that a systems biology approach is required to fully understand the complex interplay between pathogen and host.

ORGANISM(S): Homo sapiens

SUBMITTER: Atul Butte

PROVIDER: E-GEOD-1469 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Genome-wide analysis of host responses to the Pseudomonas aeruginosa type III secretion system yields synergistic effects.

Ichikawa Jeffrey K JK English Sangeeta B SB Wolfgang Matthew C MC Jackson Rebekah R Butte Atul J AJ Lory Stephen S

Cellular microbiology 20051101 11

The type III secretion system (TTSS) is a dedicated bacterial pathogen protein targeting system that directly affects host cell signalling and response pathways. Our goal was to identify host responses to the Pseudomonas aeruginosa effectors, introduced into target cells utilizing the TTSS. We carried out expression profiling of a human lung pneumocyte cell line A549 exposed to isogenic mutants of P. aeruginosa PAK lacking individual or a combination of TTSS components. We then devised a data an ...[more]

PMID: 16207250

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Project description:Pseudomonas syringae pv. tomato DC3000 (Pst) is a virulent pathogen, which causes disease on tomato and Arabidopsis. The type III secretion system (TTSS) plays a key role in pathogenesis by translocating virulence effectors from the bacteria into the plant host cell, while the phytotoxin coronatine (COR) contributes to virulence and disease symptom development. Recent studies suggest that both the TTSS and and COR are involved in the suppression of host basal defenses. However, little is known about the interplay between the host gene expression associated with basal defenses and the virulence activities of the TTSS and COR during infection. The global effects of the TTSS and COR on host gene expression associated with other host cellular processes during bacterial infection are also not well characterized. In this study, we used the Affymetrix full genome chip to determine the Arabidopsis transcriptome associated with basal defense to Pst DC3000 hrp mutants and the human pathogenic bacterium Escherichia coli O157:H7. We then used Pst DC3000 virulence mutants to characterize Arabidopsis transcriptional responses to the action of hrp-regulated virulence factors (e.g., TTSS and COR) during bacterial infection. Additionally, we used bacterial fliC mutants to assess the role of the PAMP flagellin in induction of basal defense-associated transcriptional responses. In total, our global gene expression analysis identified more than 5000 Arabidopsis genes that are reproducibly regulated more than 2-fold in three independent biological replicates of at least one type of comparison. Regulation of these genes provides a molecular signature for Arabidopsis basal defense to plant and human pathogenic bacteria, and illustrates both common and distinct global virulence effects of the TTSS, COR, and possibly other hrp-regulated virulence factors during Pst DC3000 infection. Experimenter name = William Underwood; Experimenter phone = 517-353-9182; Experimenter fax = 517-353-9168; Experimenter address = Michigan State University; Experimenter address = 222 Plant Biology Building; Experimenter address = 178 Wilson R.d. Experimenter address = East Lansing, MI; Experimenter zip/postal_code = 48824; Experimenter country = USA Experiment Overall Design: 40 samples were used in this experiment

Project description:Global expression profiling of airway epithelial cells infected with Pseudomonas aeruginosa and the rsmA mutant. Recent work in our laboratory investigated the impact of RsmA on a number of airway epithelial cell phenotypes including actin depolymerization, cytotoxicity and invasion. These cellular phenotypes were influenced by the positive effect of RsmA on the expression of the TTSS in P. aeruginosa (Mulcahy et al. 2006. Infect. Immun.). Pseudomonas aeruginosa is an important opportunistic pathogen which is capable of causing both acute and chronic infections in immunocompromised patients. Successful adaptation of the bacterium to its host environment relies on the ability of the organism to tightly regulate gene expression. RsmA, a small RNA-binding ; protein, controls the expression of a large number of virulence-related genes in P. aeruginosa, including those encoding the type III secretion system and associated effector proteins, with important consequences for epithelial cell morphology and cytotoxicity. In order to examine the influence of RsmA-regulated functions in ; the pathogen on gene expression in the host, we compared global expression profiles of airway epithelial cells in response to infection with P. aeruginosa PAO1 and an rsmA mutant. The RsmA-dependent response of host cells was characterized by significant changes in the global transcriptional pattern, including the increased expression of two Kruppel-like factors, KLF2 and KLF6. This increased expression was mediated by specific type III effector proteins. ExoS was required for the enhanced expression of KLF2, whereas both ExoS and ExoY were required for the enhanced expression of KLF6. Neither ExoT nor ExoU influenced the expression of the transcription factors. Additionally, the increased gene expression of KLF2 and KLF6 was associated with ExoS-mediated cytotoxicity. Therefore, this study identifies for the first time the human transcription factors ; KLF2 and KLF6 as targets of the P. aeruginosa type III exoenzymes S and Y, with potential importance in host cell death. Experiment Overall Design: RNA isolation and microarray sample preparation Experiment Overall Design: Biological samples from two independent infection experiments were used in two independent microarray experiments as outlined below. Total RNA was isolated from epithelial cells using a RNeasy Kit (Qiagen) according to manufacturer's instructions. Genomic DNA was removed using DNA-free (Ambion) and confirmed by PCR to be free of DNA, prior to cDNA synthesis. Isolated RNA was used in the preparation of fragmented cRNA for microarray hybridization according to the manufacturer's protocol (Affymetrix). Briefly, 8.5ug of RNA was converted to double stranded cDNA by reverse transcription, using a Superscript cDNA synthesis kit (Invitrogen), with an oligo dT primer containing a T7 RNA polymerase site added 3' of the poly (T) (Affymetrix). After second strand synthesis, cDNA was converted to biotin-labelled cRNA by in vitro transcription (Enzo). The labelled cRNA was purified using Genechip clean up module (Qiagen). Total cRNA quality and yield was measured using a GeneQuant spectrophotometer and 20ug of cRNA was fragmented at 94ÂºC for 35 mins in fragmentation buffer (40 mM tris acetate, pH 8.1, 100 mM potassium acetate, 30 mM magnesium acetate). Full length and fragmented cRNA sample integrity was assessed by electrophoresis on a 1% agarose-TBE gel visualized by staining with SyBr green. Fragmented cRNA was sent to MRC geneservice (Cambridge, UK) for assessment of RNA quality using a Bioanalyzer (Agilent) before hybridization and scanning. The arrays were washed and stained in a fluidics station and scanned according to the manufacturer's protocols (Affymetrix). Experiment Overall Design: Microarray data analysis Experiment Overall Design: Raw image analysis was performed using Microarray Suite v5.0 software (Affymetrix). Downstream data analysis was performed using GeneSight software version 2.7 (Biodiscovery). For all analyses, the signal intensities from two independent infection and microarray experiments were used. Statistically significant changes in gene expression were identified by firstly performing analysis of variance (ANOVA), for comparison between multiple groups, with a P value of < 0.05. The list of transcripts generated using ANOVA was then subjected to a Student's t-test, for comparison between two groups, with a P value of < 0.05. To identify different levels of gene expression compared to baseline, a fold change cut-off of greater than or equal to 1.5 was applied to this data.

Project description:Pseudomonas syringae pv. tomato DC3000 (Pst) is a virulent pathogen, which causes disease on tomato and Arabidopsis. The type III secretion system (TTSS) plays a key role in pathogenesis by translocating virulence effectors from the bacteria into the plant host cell, while the phytotoxin coronatine (COR) contributes to virulence and disease symptom development. Recent studies suggest that both the TTSS and and COR are involved in the suppression of host basal defenses. However, little is known about the interplay between the host gene expression associated with basal defenses and the virulence activities of the TTSS and COR during infection. The global effects of the TTSS and COR on host gene expression associated with other host cellular processes during bacterial infection are also not well characterized. In this study, we used the Affymetrix full genome chip to determine the Arabidopsis transcriptome associated with basal defense to Pst DC3000 hrp mutants and the human pathogenic bacterium Escherichia coli O157:H7. We then used Pst DC3000 virulence mutants to characterize Arabidopsis transcriptional responses to the action of hrp-regulated virulence factors (e.g., TTSS and COR) during bacterial infection. Additionally, we used bacterial fliC mutants to assess the role of the PAMP flagellin in induction of basal defense-associated transcriptional responses. In total, our global gene expression analysis identified more than 5000 Arabidopsis genes that are reproducibly regulated more than 2-fold in three independent biological replicates of at least one type of comparison. Regulation of these genes provides a molecular signature for Arabidopsis basal defense to plant and human pathogenic bacteria, and illustrates both common and distinct global virulence effects of the TTSS, COR, and possibly other hrp-regulated virulence factors during Pst DC3000 infection. Experimenter name = William Underwood Experimenter phone = 517-353-9182 Experimenter fax = 517-353-9168 Experimenter address = Michigan State University Experimenter address = 222 Plant Biology Building Experimenter address = 178 Wilson R.d. Experimenter address = East Lansing, MI Experimenter zip/postal_code = 48824 Experimenter country = USA Keywords: pathogenicity_design

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Dataset Information

Transcription profiling of human A549 pneumocyte cells infected with wild type and type III secretion system mutants of Pseudomonas aeruginosa

Publications

Genome-wide analysis of host responses to the Pseudomonas aeruginosa type III secretion system yields synergistic effects.

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