Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Bovine Peyer's Patch Infected with Mycobacterium avium ssp. paratuberculosis and Mycobacterium avium ssp. avium

ABSTRACT: 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.

ORGANISM(S): Bos taurus

SUBMITTER: Leslie Adams

PROVIDER: E-GEOD-13888 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Systems biology analysis of gene expression during in vivo Mycobacterium avium paratuberculosis enteric colonization reveals role for immune tolerance.

Khare Sangeeta S Lawhon Sara D SD Drake Kenneth L KL Nunes Jairo E S JE Figueiredo Josely F JF Rossetti Carlos A CA Gull Tamara T Everts Robin E RE Lewin Harris A HA Galindo Cristi L CL Garner Harold R HR Adams Leslie Garry LG

PloS one 20120817 8

Survival and persistence of Mycobacterium avium subsp. paratuberculosis (MAP) in the intestinal mucosa is associated with host immune tolerance. However, the initial events during MAP interaction with its host that lead to pathogen survival, granulomatous inflammation, and clinical disease progression are poorly defined. We hypothesize that immune tolerance is initiated upon initial contact of MAP with the intestinal Peyer's patch. To test our hypothesis, ligated ileal loops in neonatal calves w ...[more]

PMID: 22912686

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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:Classical antiviral therapy inhibit viral proteins and are subject to resistance. To counteract this emergence, alternative strategy has been developed that target cellular factors. We hypothesized that such approach could also be useful to identify broad antivirals. Influenza A virus was used as a model for viral diversity and need for therapy against unpredictable viruses as recently underlined by the H1N1 pandemic. We proposed to identify a gene-expression signature associated with infection with different influenza A virus subtypes which could help to identify potential antiviral drugs with broad spectrum. Cellular gene expression response to infection with five different human and avian influenza viruses strains was analyzed and 300 genes were determined as differentially expressed between infected and non-infected samples. Strikingly, only a few genes were induced by infection and related to immune response. A more concise list was used to screen connectivity map, a database of drug-associated gene expression profiles, for molecules with inverse profiles than the signature of infection. We hypothesized that such compounds would induce an unfavorable cellular environment for influenza virus replication. Eight potential antivirals including ribavirin were identified, and six inhibited influenza viral growth in vitro. The new pandemic H1N1 virus, which was not used to define the gene expression signature of infection, was inhibited by five of the eight identified molecules, demonstrating that this strategy could help to identify broad spectrum antivirals. This is the first study showing that a gene expression based-screening can be used to identify antivirals. Such approaches could accelerate the drug discovery progress and could be extended to other pathogens. A549 (human lung epithelial cells) were infected with 5 different influenza A strains (A/New Caledonia/20/99 (H1N1), A/Moscow/10/99 (H3N2), A/Lyon/969/09 (H1N1 SOI-V), A/Turkey/582/2006 (H5N1), A/Finch/England/2051/94 (H5N2), and A/Chicken/Italy/2076/99 (H7N1)) or mock infected. Five independant replicates were done and hybridized on a different microarray. The overall design is thus composed of 5 mock samples, and 5x5 infected samples.

Project description:Background: Mycobacterium avium subspecies paratuberculosis (MPTb) is the causative agent of Johne’s disease, an intestinal disease of ruminants with major economic consequences. MPTb bacilli are phagocytosed by host macrophages upon exposure where they persist, resulting in lengthy subclinical phases of infection that can lead to immunopathology and disease dissemination. Consequently, analysis of the macrophage transcriptome in response to MPTb infection can provide valuable insights into the molecular mechanisms that underlie Johne’s disease. Here, we investigate pan-genomic gene expression in bovine monocyte-derived macrophages (MDM) purified from seven age-matched non-related females, in response to in vitro infection with MPTb (multiplicity of infection 2:1) at intervals of 2 hours, 6 hours and 24 hours post-infection. Results: Differentially expressed genes were identified by comparing the transcriptomes of the infected MDM to the control MDM at each time point (adjusted P-value threshold ≤ 0.10). 1,050 differentially expressed unique genes were identified 2 hours post-infection, with 974 and 84 differentially expressed unique genes detected 6 hours and 24 hours post-infection, respectively. Furthermore, in the infected MDM the number of upregulated genes exceeded the number of downregulated genes at each time point, with the fold-change in expression for the upregulated genes markedly higher than that for the downregulated genes. Conclusions: Inspection and systems analysis of the differentially expressed genes revealed changes in the expression profiles of genes involved in the inflammatory response, cell signalling pathways and apoptosis. The transcriptional changes associated with cellular signalling and the inflammatory response may reflect different immuno-modulatory mechanisms that underlie host-pathogen interactions during infection. Affymetrix GeneChip® Bovine Genome Arrays were used to examine gene expression of bovine monocyte-derived macrophages (MDM) after in vitro challenge with Mycobacterium avium subspecies paratuberculosis across a time series of 2 hr, 6 hr and 24 hr post-challenge. A 0 hr control treatment was also generated and seven different age-matched female Holstein-Friesian cattle were used for each time-point/treatment combination for a total of 49 microarrays, one of which was excluded from analysis since it did not pass quality control.

Dataset Information

Bovine Peyer's Patch Infected with Mycobacterium avium ssp. paratuberculosis and Mycobacterium avium ssp. avium

Publications

Systems biology analysis of gene expression during in vivo Mycobacterium avium paratuberculosis enteric colonization reveals role for immune tolerance.

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