Project description:We focused on how Mycobacterium avium subsp. paratuberculosis influences the subsequent host response to investigate the host immunopathology accompanying the host anti-mycobacterial immune response during Mycobacterium avium subsp. paratuberculosis infection in spleen of mice.
Project description:BackgroundMaintenance of metal homeostasis is crucial in bacterial pathogenicity as metal starvation is the most important mechanism in the nutritional immunity strategy of host cells. Thus, pathogenic bacteria have evolved sensitive metal scavenging systems to overcome this particular host defence mechanism. The ruminant pathogen Mycobacterium avium ssp. paratuberculosis (MAP) displays a unique gut tropism and causes a chronic progressive intestinal inflammation. MAP possesses eight conserved lineage specific large sequence polymorphisms (LSP), which distinguish MAP from its ancestral M. avium ssp. hominissuis or other M. avium subspecies. LSP14 and LSP15 harbour many genes proposed to be involved in metal homeostasis and have been suggested to substitute for a MAP specific, impaired mycobactin synthesis.ResultsIn the present study, we found that a LSP14 located putative IrtAB-like iron transporter encoded by mptABC was induced by zinc but not by iron starvation. Heterologous reporter gene assays with the lacZ gene under control of the mptABC promoter in M. smegmatis (MSMEG) and in a MSMEG∆furB deletion mutant revealed a zinc dependent, metalloregulator FurB mediated expression of mptABC via a conserved mycobacterial FurB recognition site. Deep sequencing of RNA from MAP cultures treated with the zinc chelator TPEN revealed that 70 genes responded to zinc limitation. Remarkably, 45 of these genes were located on a large genomic island of approximately 90 kb which harboured LSP14 and LSP15. Thirty-five of these genes were predicted to be controlled by FurB, due to the presence of putative binding sites. This clustering of zinc responsive genes was exclusively found in MAP and not in other mycobacteria.ConclusionsOur data revealed a particular genomic signature for MAP given by a unique zinc specific locus, thereby suggesting an exceptional relevance of zinc for the metabolism of MAP. MAP seems to be well adapted to maintain zinc homeostasis which might contribute to the peculiarity of MAP pathogenicity.
Project description:Mycobacterium avium subspecies paratuberculosis (MAP) infection is established following the ingestion of bacteria, their penetration of the intestinal mucosa and subsequent events of the host-parasite interaction. These bacteria invade M cells, macrophages and are capable of resisting host defenses and multiply to reach very high numbers intracellular. Mycobactrium avium subsp. avium (MAA) is an antigenically and genetically similar organisms but is relatively nonpathogenic for cattle. MAA organisms appear to infect cattle, but unlike cattle infected with MAP, cattle infected with MAA typically mount an effective systemic immune response, form caseous granuloma, and eliminate the infection. This study was designed to understand the similarities and differences in the host responses during MAP and MAA infection. Neonatal calves were infected (ligated ileal loops) with PBS, MAP, or avirulent MAA following which samples were collected at 30 min, 1h, 2h, 4h, 8h, or 12h. Post-infection, RNA was collected, processed, and then hybridized to custom bovine gene expression arrays, each of which represented 13,258 transcripts spotted in duplicate. Arrays were normalized by scaling against the average reference intensity value (i.e., average across all arrays), normalized by global mean, and then log transformed before statistical analyses were performed. Pairwise comparisons of averaged signal values and Student’s t test were performed using GeneSifter software (VizX Labs, Seattle, WA). A fold-change of at least 1.5-fold and a p value of 0.05 or less was required for a difference in signal to be considered statistically significant. When comparing the transcriptional responses of calves infected with the MAA versus MAP, unique patterns of expression were clearly visible. In general, numbers of transcripts altered in response to infection were much greater for MAA-infected animals than for those infected with the MAP. No genes were significantly up-regulated in MAP-infected animals at the earliest time point tested (30 min), and only modest numbers of genes were increased in expression over the experimental time course. On the other hand, up-regulated transcripts were detected by 30 min in MAA-infected animals and peaked by 2 hr. Differences in the numbers of down-regulated genes between MAP-infected and MAA-infected animals (compared to PBS-infected controls) were less pronounced. At the earliest time points, MAP-infected calves had a greater number of down-regulated genes than did animals infected with MAA. This trend was reversed at 8 and 12 hr post-infection. Keywords: Gene expression profiling by microarray
Project description:We focused on how Mycobacterium avium subsp. paratuberculosis influences the subsequent host response to investigate the host immunopathology accompanying the host anti-mycobacterial immune response during Mycobacterium avium subsp. paratuberculosis infection in spleen of mice. We analyzed altered transcription in the spleen of mice at 3, 6, and 12 weeks following Mycobacterium avium subsp. paratuberculosis infection.
Project description:Transcriptional profiling of M. avium subsp. paratuberculosis inside bovine monocyte-derived macrophages (MDMs; in vitro infection) during phagosome acidification at 30 min post-infection. M. avium subsp. paratuberculosis profiles from bafilomcyin A1 (acidification inhibitor) treated and untreated monocyte-derived macrophages were compared.
Project description:Mycobacterium avium subspecies paratuberculosis (MAP) infection is established following the ingestion of bacteria, their penetration of the intestinal mucosa and subsequent events of the host-parasite interaction. These bacteria invade M cells, macrophages and are capable of resisting host defenses and multiply to reach very high numbers intracellular. Mycobactrium avium subsp. avium (MAA) is an antigenically and genetically similar organisms but is relatively nonpathogenic for cattle. MAA organisms appear to infect cattle, but unlike cattle infected with MAP, cattle infected with MAA typically mount an effective systemic immune response, form caseous granuloma, and eliminate the infection. This study was designed to understand the similarities and differences in the host responses during MAP and MAA infection. Neonatal calves were infected (ligated ileal loops) with PBS, MAP, or avirulent MAA following which samples were collected at 30 min, 1h, 2h, 4h, 8h, or 12h. Post-infection, RNA was collected, processed, and then hybridized to custom bovine gene expression arrays, each of which represented 13,258 transcripts spotted in duplicate. Arrays were normalized by scaling against the average reference intensity value (i.e., average across all arrays), normalized by global mean, and then log transformed before statistical analyses were performed. Pairwise comparisons of averaged signal values and StudentM-bM-^@M-^Ys t test were performed using GeneSifter software (VizX Labs, Seattle, WA). A fold-change of at least 1.5-fold and a p value of 0.05 or less was required for a difference in signal to be considered statistically significant. When comparing the transcriptional responses of calves infected with the MAA versus MAP, unique patterns of expression were clearly visible. In general, numbers of transcripts altered in response to infection were much greater for MAA-infected animals than for those infected with the MAP. No genes were significantly up-regulated in MAP-infected animals at the earliest time point tested (30 min), and only modest numbers of genes were increased in expression over the experimental time course. On the other hand, up-regulated transcripts were detected by 30 min in MAA-infected animals and peaked by 2 hr. Differences in the numbers of down-regulated genes between MAP-infected and MAA-infected animals (compared to PBS-infected controls) were less pronounced. At the earliest time points, MAP-infected calves had a greater number of down-regulated genes than did animals infected with MAA. This trend was reversed at 8 and 12 hr post-infection. Keywords: Gene expression profiling by microarray Microarrays were used to examine the transcriptional profiles of bovine intestinal mucosa inoculated with PBS, MAP or MAA and across six time points (30 min, 1, 2, 4, 8, and 12 hours). Experiments were performed in quadruplicate for PBS, MAP, and MAA (bovine ligated ileal loops surgeries were performed with four calves). For one surgery, MAA was used for 4 time ponts only, thus generateing a total of 70 arrays.
Project description:This SuperSeries is composed of the following subset Series: GSE32241: Differentially regulated genes induced in Mycobacterium avium subspecies paratuberculosis by in vitro acid-nitrosative multi-stress GSE32242: Differentially regulated genes induced in Mycobacterium avium subspecies paratuberculosis by in vitro infection of THP-1 human macrophage cell line Refer to individual Series
Project description:Detection of species-specific proteotypic peptides for accurate and easy characterization of infectious non-tuberculous mycobacteria such as Mycobacterium avium subsp. paratuberculosis is essential. Therefore, we conducted an in-depth global proteomic experiment using M. avium subsp. paratuberculosis ATCC 19698 (Map) strain followed by proteome database search and spectral library generation. The lysate was subjected to in-solution proteomic sample preparation and fractionated using an offline C18 StageTip. Each fraction was acquired in technical triplicates using a 180 min data-dependent acquisition (DDA) method in Orbitrap Fusion Tribrid (Thermo Scientific) mass spectrometer. The resulting raw DDA data were searched against the M. avium subsp. paratuberculosis proteome database using Proteome Discoverer and FragPipe. The resulting peptide spectrum matches were converted into a spectral library using BiblioSpec.
Project description:To provide novel insights into understanding the host-immune response during the different stages of progression of the disease, we performed gene expression profiling in Mycobacterium avium subsp. paratuberculosis infection in cattle.
Project description:Transcriptional profiling of M. avium subsp. paratuberculosis inside bovine monocyte-derived macrophages (MDMs; in vitro infection) during phagosome acidification at 30 min post-infection. M. avium subsp. paratuberculosis profiles from bafilomcyin A1 (acidification inhibitor) treated and untreated monocyte-derived macrophages were compared. Two-condition experiment; 3 control (bafilomcyin treated) and 3 test, independently conducted. 1 control, 1 test per microarray.