Small RNA profiling of human blood derived macrophages upon infection with Legionella Pneumophila
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE125559 | GEO | 2019/01/25
REPOSITORIES: GEO
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Project description:wt and MyD88-/- murine bone marrow derived macrophages were infected with Legionella Pneumophila for 24h. RNA was isolated by phenol/chloroform precipitation. 400 ng RNA per sample were then reverse transcribed with the Life Technologies miR RT kit with megaplex primers. Reverse transcribed RNA was then loaded on the rodent Taqman Low Density Array (TLDA) Cards and run according to manufacturer´s recommendations
2017-06-12 | GSE92600 | GEO
Project description:Legionella pneumophila is the causative agent of Legionnaires’ disease, an acute pulmonary infection. L. pneumophila is able to infect and multiply in both phagocytic protozoan, such as Acanthamoeba castellanii, and mammalian professional phagocytes. The best-known virulence determinant used by L. pneumophila to infect host cells is a Type IVb translocation system named Icm/Dot, which is used to modify the host cell functions to the benefit of the bacteria. To date the Icm/Dot systeme is known to translocate more than 100 effectors. While the transcriptional response of Legionella to the intracellular environement of A. castelannii as already been investigated, much less is known of how Legionella reacts transcriptionnally inside human macrophages. In this study, the transcriptome of L. pneumophila was monitored during exponential and post-exponential phase in rich AYE broth and during infection of human cultured macrophages by using microarray and a RNA amplification procedure called SCOTS to allow for the study of conditions of low bacterial loads. Among the genes induced intracellularly are those involved in amino acid synthesis pathway leading to L-arginine, L-histidne and L-proline as well as many transport system involved in amino acid and iron uptake. The Icm/Dot systems is not differentially expressed inside cells compare to the E phase control but the effectors are strongly induced. The intracellular transcriptome was further used to identify putative new Icm/Dot effectors and translocation was show to occur for 3 of them. This study provides a comprehensive view of how L. pneumophila react to the human macrophages intracellular environment.
2011-01-01 | GSE23029 | GEO
Project description:The objective of this study is to determine changes in the global transcriptome of human macrophages upon infection with Legionella pneumophila and two isogenic mutants, LamA and AnkH
2019-08-14 | GSE135803 | GEO
Project description:Legionella pneumophila was exposed for 3h to 160 ug/ml of CuO nanoparticle. Untreated samples are used as the control condition.
2013-03-04 | GSE41966 | GEO
Project description:Abstract Legionella pneumophila, the causative agent of Legionnaire’s disease, grows within macrophages and manipulates target cell signaling. Formation of a Legionella-containing replication vacuole requires the function of the bacterial type IV secretion system (Dot/Icm), which transfers protein substrates into the host cell cytoplasm. A global microarray analysis was used to examine the response of human macrophage-like U937 cells to low dose infections with L. pneumophila. The most striking change in expression was the Dot/Icm-dependent up-regulation of anti-apoptotic genes positively controlled by the transcriptional regulator NF-?B. Consistent with this finding, L. pneumophila triggered nuclear localization of NF-?B in human and mouse macrophage in a Dot/Icm-dependent manner. The mechanism of activation at low dose infections involved a signaling pathway that occurred independently of the TLR adaptor MyD88, and cytoplasmic sensor Nod1. In contrast, high MOI conditions caused a host cell response that masked the unique Dot/Icm-dependent activation of NF-?B. Inhibition of NF-?B translocation into the nucleus resulted in premature host cell death and termination of bacterial replication. In the absence of one anti-apoptotic protein, PAI-2, host cell death increased in response to L. pneumophila infection, indicating that induction of anti-apoptotic genes is critical for host cell survival. Keywords: time course, dose response
2006-08-17 | GSE5551 | GEO
Project description:Legionella pneumophila is the causative agent of Legionnaires’ disease, an acute pulmonary infection. L. pneumophila is able to infect and multiply in both phagocytic protozoan, such as Acanthamoeba castellanii, and mammalian professional phagocytes. The best-known virulence determinant used by L. pneumophila to infect host cells is a Type IVb translocation system named Icm/Dot, which is used to modify the host cell functions to the benefit of the bacteria. To date the Icm/Dot systeme is known to translocate more than 100 effectors. While the transcriptional response of Legionella to the intracellular environement of A. castelannii as already been investigated, much less is known of how Legionella reacts transcriptionnally inside human macrophages. In this study, the transcriptome of L. pneumophila was monitored during exponential and post-exponential phase in rich AYE broth and during infection of human cultured macrophages by using microarray and a RNA amplification procedure called SCOTS to allow for the study of conditions of low bacterial loads. Among the genes induced intracellularly are those involved in amino acid synthesis pathway leading to L-arginine, L-histidne and L-proline as well as many transport system involved in amino acid and iron uptake. The Icm/Dot systems is not differentially expressed inside cells compare to the E phase control but the effectors are strongly induced. The intracellular transcriptome was further used to identify putative new Icm/Dot effectors and translocation was show to occur for 3 of them. This study provides a comprehensive view of how L. pneumophila react to the human macrophages intracellular environment. The aim of this work was to study the gene expression profile of Legionella during infection of macrophages infected at a low multiplicity of infection (MOI). SCOTS is a method that allows amplification of small amounts of bacterial RNA from infected host cells, while discarding host cell transcripts and ribosomal RNA. Before infection, macrophages derived from the THP-1 monocyte cell line were pre-treated with antibodies against the L. pneumophila major outer membrane protein, which increases the efficiency of bacterial entry into host cells . After 2 hours of infection, the macrophages were washed and treated with gentamicin for 1 hour, to synchronize the infection and kill extracellular bacteria, and cells were washed 3 times and fresh medium was added. Samples for the first time point (T0) were collected after the gentamicin treatment. Samples were also collected after 6h (T6) and 18h (T18). Samples from all conditions, including growth in AYE broth to exponential (E) or post exponential (PE) phase, were treated with three consecutive rounds of SCOTS and the resulting cDNA was labeled and hybridized to the microarray slides. As a reference channel, labeled gDNA was also hybridized. For each condition studied, three independent biological replicates and two technical replicates were analyzed, resulting in six replicates for each condition. The data was background subtracted and normalized by calculating the contribution of each spot to the total intensity and the ratio to gDNA was recorded. A one tailed student's T test was used for statistical analysis and the ratio between test conditions (PE, T0, T6 and T18) and the control conditions (E phase or T0) was calculated.
2011-01-01 | E-GEOD-23029 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the following subset Series: GSE19196: Detection of predicted small RNA of Legionella pneumophila GSE19200: Gene affected by deletion of 6S RNA in post-exponential phase Refer to individual Series
2010-06-24 | E-GEOD-19451 | biostudies-arrayexpress
Project description:Legionella pneumophila cells were harvested during exponential growth (RP) and stationary growth (TP). VBNC cells were also anylzed. Protein subfractions were studied.
2015-11-13 | PXD001926 | Pride
Project description:Legionella pneumophila is a gram-negative opportunistic human pathogen that infects and multiplies in a broad range of phagocytic protozoan and mammalian phagocytes. Based on the observation that small regulatory RNAs (sRNAs) play an important role in controlling virulence-related genes in several pathogenic bacteria, we attempted to test the hypothesis that sRNAs play a similar role in L. pneumophila. We used computational prediction followed by experimental verification to identify and characterize sRNAs encoded in the L. pneumophila genome. A 50-mer probe microarray was constructed to test the expression of predicted sRNAs in bacteria grown under a variety of conditions. This strategy successfully identified 22 expressed RNAs, out of which six were confirmed by northern blot and RACE. One of the identified sRNAs is highly expressed when the bacteria enter post exponential phase and computational prediction of its secondary structure reveals a striking similarity to the structure of 6S RNA, a widely distributed prokaryotic sRNA, known to regulate the activity of σ70-containing RNAP. A 70-mer probe microarray was used to identify genes affected by L. pneumophila 6S RNA in stationary phase. The 6S RNA encoded by the ssrS gene positively regulates expression of genes encoding type IVB secretion system effectors, stress response genes such as groES and recA as well as many genes with unknown or hypothetical functions. Deletion of 6S RNA significantly reduced L. pneumophila intracellular multiplication in both protist and mammalian host cells, but had no detectable effect on growth in rich media.
2010-01-01 | GSE19196 | GEO