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
Project description:Microarray analysis of Myd88-/-Trif-/- and Myd88-/-Rip2-/- macrophage responses to WT or dotA mutant L. pneumophila. Experiment Overall Design: Bone marrow-derived macrophages from Myd88-/-Trif-/- and Myd88-/-Rip2-/- mice were infected with WT L. pneumophila (Lp02) or dotA mutant L. pneumophila (Lp03) for 4 hours. The RNA was extracted, processed, and hybridized onto Affymetrix 430 2.0 microarrays
Project description:Legionella pneumophila is an opportunistic bacterial pathogen that causes a severe lung infection termed “Legionnaires’ disease”. The pathogen replicates in environmental protozoa as well as in macrophages within a unique membrane-bound compartment, the Legionella-containing-vacuole (LCV). Formation of the pathogen vacuole requires the bacterial Icm/Dot type IV secretion system (T4SS), which translocates ca. 300 effector proteins into host cells, where they subvert pivotal host processes and govern LCV formation. The L. pneumophila “pentuple” mutant lacks 5 gene clusters comprising 12% of the genome and 30% of the effector proteins. The mutant strain replicates in murine bone marrow-derived macrophages but not in Dictyostelium discoideum amoeba. In order to elucidate the host cell proteome defining a replication permissive compartment, we compare here the proteomes of intact LCVs isolated from D. discoideum or murine RAW 264.7 macrophages infected with the L. pneumophila parental strain Lp02 or the “pentuple” mutant. Proteome analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed host proteins specifically localizing to LCVs harbouring strain Lp02 or the “pentuple” mutant, respectively. The small GTPase Rap1 was identified on D. discoideum LCVs containing strain Lp02 but not the “pentuple” mutant and on macrophage LCVs containing either strain. The localization pattern of Rap1 on D. discoideum LCVs was confirmed by fluorescence microscopy, and depletion of Rap1 in A549 epithelial cells by RNA interference significantly reduced the intracellular growth of L. pneumophila. Thus, comparative proteomics identified Rap1 as a novel LCV host component implicated in intracellular replication of L. pneumophila.
Project description:WT control or MyD88 deficient bone marrow derived macrophages were stimulated with TLR2, TLR3, TLR4, TLR7, and TLR9 ligands for 48 h.
Project description:MyD88 may play a direct role in STING-dependent signaling, or alternatively that STING-dependent pro-inflammatory cytokines may require downstream MyD88-dependent signaling to exert their effect. To determine this, we treated STING or MyD88-deficient murine embryonic fibroblasts (MEFs), bone marrow derived macrophages (BMDM) or dendritic cells (BMDC) with exogenous CDN’s or cytosolic dsDNA (ISD) which triggers STING-signaling and type I IFN production.
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
Project description:The intracellular bacterial pathogen Legionella pneumophila causes an inflammatory pneumonia called Legionnaires’ Disease. For virulence, L. pneumophila requires a Dot/Icm type IV secretion system that translocates bacterial effectors to the host cytosol. L. pneumophila lacking the Dot/Icm system is recognized by Toll-like receptors (TLRs), leading to a canonical NF-κB-dependent transcriptional response. In addition, L. pneumophila expressing a functional Dot/Icm system potently induces unique transcriptional targets, including proinflammatory genes such as Il23a and Csf2. Here we demonstrate that this Dot/Icm-dependent response, which we term the effector-triggered response (ETR), requires five translocated bacterial effectors that inhibit host protein synthesis. Upon infection of macrophages with virulent L. pneumophila, these five effectors caused a global decrease in host translation, thereby preventing synthesis of IκB, an inhibitor of the NF-κB transcription factor. Thus, macrophages infected with wildtype L. pneumophila exhibited prolonged activation of NF-κB, which was associated with transcription of ETR target genes such as Il23a and Csf2. L. pneumophila mutants lacking the five effectors still activated TLRs and NF-κB, but because the mutants permitted normal IκB synthesis, NF-κB activation was more transient and was not sufficient to fully induce the ETR. L. pneumophila mutants expressing enzymatically inactive effectors were also unable to fully induce the ETR, whereas multiple compounds or bacterial toxins that inhibit host protein synthesis via distinct mechanisms recapitulated the ETR when administered with TLR ligands. Previous studies have demonstrated that the host response to bacterial infection is induced primarily by specific microbial molecules that activate TLRs or cytosolic pattern recognition receptors. Our results add to this model by providing a striking illustration of how the host immune response to a virulent pathogen can also be shaped by pathogen-encoded activities, such as inhibition of host protein synthesis. Four-condition experiment: macrophages left uninfected (negative control), or infected with wildtype Legionella pneumophila, the flagellin-deficient mutant ΔflaA, or the secretion-deficient mutant ΔdotA (three experimental conditions). Biological replicates: two, independently infected, harvested, and hybridized to arrays. One to two technical replicates per array, as indicated in file titles.
Project description:IL-6 induces IL4ralpha expression in macrophages. This mechanism is necessary to promote macrophage polarization towards an M2-phenotype and is crucial to limit the inflammatory response both upon obesity and LPS-endotoxemia. In this dataset, we include the expression data obtained from primary murine bone marrow-derived macrophages from control and IL6ralpha-deficient macrophages (n=4vs4) stimulated with interleukin-6 (IL-6) 8 samples were analyzed to compare control and IL6ralpha-deficient macrophages for their gene expression profiles upon stimulation with IL-6
