Unknown,Transcriptomics,Genomics,Proteomics

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Characterization of the inflammatory phenotype of Mycobacterium avium subspecies paratuberculosis

ABSTRACT: Understanding the pathogenic mechanisms and host responses to Johne's disease, caused by Mycboacterium avium subspecies paratuberculosis (MAP), is complicated by a number of challenges of the disease progression and lack of ex vivo models to study the disease. We describe novel cell culture passage model which mimics the course of infection in vivo. Using this model we determined that cell culture passaged MAP develops an inflammatory phenotype initiating higher levels of pro-inflammatory cytokines and chemokines compared to levels initiated by non-passaged MAP. To verify that the MAP phenotypes were changing, we conducted transcriptome analysis of each population during the passage model and identified a change in gene expression, specifically and upregulation of genes involved in the biosynthesis of lipid components within the cell. Lipidomic analysis showed dramatically different lipid profiles between the 2 populations. These transcriptome changes were validated by the identification of high levels of upregulated transcripts from MAP-infected cattle ileal tissue. In total, this study described a novel model used to show that MAP changes phenotype during intracellular passage, thus changing its lipid profile and triggering an inflammatory response in the host leading to the severe clinical phage of Johne's disease. In total 6 slides were analyzed. Of the 2 phenotypes under investigation, the P0 samples (non-inflammatory) were analyzed in triplate and the P2 samples (inflammatory) were analyzed in triplicate. Each slide fluorescence intensity was measured at PMT400, 600 and 750. Each oligo on each slide was spotted in triplicate and each slide had its own internal controls.

ORGANISM(S): Mycobacterium avium subsp. paratuberculosis

SUBMITTER: Luiz Bermudez

PROVIDER: E-GEOD-62566 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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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 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:Renal cancer accounts for 2% to 3% of all adult malignancies in the US. In 2011 more than 64,770 new cases and 13,000 deaths were reported and the incidence is steadily increasing by 2.5% per year. Clear cell renal carcinoma (ccRCC) represents the majority (85% to 90%) of adult kidney cancers and is the most malignant. This cancer is characterized by an early loss of the von Hippel-Lindau tumor suppressor (VHL) on short arm of chromosome 3 in the majority of tumors (80%). It is a classic knowledge that loss of VHL results in an increased accumulation and activity of the hypoxia-inducible transcription factor (HIF), which in turns activates expression of genes promoting tumor growth. In that respect, induction of angiogenic factors induces blood flow through the tumors and delivery of nutrients and oxygen to cancer cells, while induction of genes inducing anaerobic glycolysis supports adaptation to reduced nutrients availability and shifts towards metabolic pathways promoting tumor growth. Recently we have discovered another tumor suppressing pathway regulated by VHL. We found that VHL is a major regulator of the process of macroautophagy (autophagy) (ref). We identified that VHL induces expression of a microRNA, miR-204, which in turn inhibits activity of a major regulator required for the formation of autophagosome, LC3B. LC3B-mediated autophagy is necessary for the ccRCC tumor growth, and inhibition of this process by VHL and miR-204 significantly contributes to the tumor suppression. Most importantly, we discovered that VHL by inhibiting activity of HIF, induced expression and activity of an LC3B paralog, LC3C. In contrast to LC3B, LC3C acts as a tumor suppressor, indicating the specificity and complexity of different autophagic programs. Integrating these novel data with the established role of VHL in regulating angiogenesis produces a more global picture of VHL as a master tumor suppressor that regulates nutrient access for renal cancer cells from both extracellular and intracellular sources. In the process of searching for other genes induced by VHL that could participate in the tumor suppressing activity of VHL, we discovered that reconstitution of VHL in RCC cells induces enrichment of genes expressed from the Smith-Magenis locus (SM), located on the short arm of chromosome 17p11.2. Smith-Magenis syndrome is a complex neurobehevioural disorder, characterized by intellectual impairment, craniofacial and skeletal anomalies and sleep disturbance. Recently, deletions or mutations of one specific gene in the SM locus, RAI1, (retinoic acid induced 1), were shown to be responsible for the syndrome. Interestingly, this locus contains another kidney tumor suppressor gene, folliculin (FLCN), of which activity is lost in the genetic dominant disorder, Birt-Hogg-Dube syndrome (BHD). BHD is characterized by skin fibrofolliculomas, pulmonary cysts and spontaneous pneumothorax, as well as renal cancer of mixed histological types, including chromophobe, oncocytic, clear cell and papillary type. Here we show that VHL regulates expression of FLCN, and in turn FLCN contributes to the VHL-mediated suppression of tumor growth. Two-condition experiment, VHL(-) vs. VHL(+). 4 biological replicates in each group. Two dual-channel arrays with VHL(+) on Cy5 and VHL(-) on Cy3, and two dual-channel arrays with flipped samples.

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Characterization of the inflammatory phenotype of Mycobacterium avium subspecies paratuberculosis

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