Differential gene expression in CNS after scrapie infection
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ABSTRACT: Sheep scrapie is a transmissible spongiform encephalopathy (TSE), which are invariably fatalM- neurodegenerative diseases of the central nervous system (CNS). Accumulation of the misfolded prion protein, PrPSc in the CNS results in progressive neurodegenerative disease. Susceptible VRQ homozygous New Zealand Cheviot sheep were infected with standard scrapie sheep prion (SSBP/1) scrapie by inoculation in the drainage area of the prescapular lymph nodes. PrPSc was consistently detected by immunohistology in the CNS at XX days post infection (dpi). This study compares the genes and physiological pathways that are affected by the progression of TSE disease in the CNS, focusing on time points immediately before (XX dpi) and after (XX dpi) the detection of disease-associated PrPSc.
Project description:Sheep scrapie is a transmissible spongiform encephalopathy (TSE), which are invariably fatal neurodegenerative diseases of the central nervous system (CNS). Accumulation of the misfolded prion protein, PrPSc in the CNS results in progressive neurodegenerative disease. Susceptible VRQ homozygous New Zealand Cheviot sheep were infected with SSBP/1 scrapie by inoculation in the drainage area of the prescapular lymph nodes. PrPSc was consistently detected by immunohistology in the CNS at 125 days post infection (dpi). This study compares the genes and physiological pathways that are affected by the progression of TSE disease in the CNS, focusing on time points immediately before (75dpi) and at the time point when PrPSc is consistently detected in the CNS (125 dpi).
Project description:Sheep scrapie is a transmissible spongiform encephalopathy (TSE), which are invariably fatal neurodegenerative diseases of the central nervous system (CNS). Accumulation of the misfolded prion protein, PrPSc in the CNS results in progressive neurodegenerative disease. For many transmissible spongiform encephalopathies (TSEs), peripheral lymphoid tissue is an important site of PrPSc amplification but without obvious immunological consequence. Susceptible VRQ homozygous New Zealand Cheviot sheep were infected with SSBP/1 scrapie by inoculation in the drainage area of the prescapular lymph nodes. PrPSc was consistently detected by immunohistology in these nodes at 50 days post infection (dpi). This study compares the genes and physiological pathways that are affected by the progression of TSE disease in the prescapular lymph nodes, focussing on time points immediately before (10 dpi) and after (50 dpi) the detection of disease-associated PrPSc.
Project description:Sheep scrapie is a transmissible spongiform encephalopathy (TSE), which are invariably fatal neurodegenerative diseases of the central nervous system (CNS). Accumulation of the misfolded prion protein, PrPSc in the CNS results in progressive neurodegenerative disease. For many transmissible spongiform encephalopathies (TSEs), peripheral lymphoid tissue is an important site of PrPSc amplification but without obvious immunological consequence. Susceptible VRQ homozygous New Zealand Cheviot sheep were infected with SSBP/1 scrapie by inoculation in the drainage area of the prescapular lymph nodes. PrPSc was consistently detected by immunohistology in these nodes at 50 days post infection (dpi). This study compares the genes and physiological pathways that are affected by the progression of TSE disease in the prescapular lymph nodes, focusing on time points immediately before (10 dpi) and after (50 dpi) the detection of disease-associated PrPSc.
Project description:Sheep scrapie (Sc) is the classical transmissible spongiform encephalopathy (prion disease). The conversion of normal cellular prion protein (PrPC) to disease-associated prion protein (PrPSc) is a fundamental component of prion disease pathogenesis. The molecular mechanisms contributing to prion diseases and the impact of PrPSc accumulation on cellular biology are not fully understood. To define the molecular changes associated with PrPSc accumulation, primary sheep microglia were inoculated with PrPSc and then the transcriptional profile of these PrPSc-accumulating microglial cells was compared to the profile of PrPSc-lacking microglial cells using the Affymetrix Bovine Genome Array. The experimental design included three biological replicates, each with three technical replicates, and samples that were collected at the point of maximal PrPSc accumulation levels as measured by ELISA. The array analysis revealed 19 upregulated genes and 30 downregulated genes in PrPSc-accumulating microglia. Three transcripts (CCL2, SGK1, and AASDHPPT) were differentially regulated in a direction similar to previous reports from mouse or human models, whereas the response of three other transcripts (MT1E, NR4A1, PKP2) conflicted with previous reports. Overall, the results demonstrated a limited transcriptional response to PrPSc accumulation, when compared to microglia and macrophage cultures infected with other agents such as viruses and bacteria. This is the first microarray-based analysis of prion accumulation in primary cells derived from a natural TSE-host. Keywords: disease state analysis
Project description:Sheep scrapie (Sc) is the classical transmissible spongiform encephalopathy (prion disease). The conversion of normal cellular prion protein (PrPC) to disease-associated prion protein (PrPSc) is a fundamental component of prion disease pathogenesis. The molecular mechanisms contributing to prion diseases and the impact of PrPSc accumulation on cellular biology are not fully understood. To define the molecular changes associated with PrPSc accumulation, primary sheep microglia were inoculated with PrPSc and then the transcriptional profile of these PrPSc-accumulating microglial cells was compared to the profile of PrPSc-lacking microglial cells using the Affymetrix Bovine Genome Array. The experimental design included three biological replicates, each with three technical replicates, and samples that were collected at the point of maximal PrPSc accumulation levels as measured by ELISA. The array analysis revealed 19 upregulated genes and 30 downregulated genes in PrPSc-accumulating microglia. Three transcripts (CCL2, SGK1, and AASDHPPT) were differentially regulated in a direction similar to previous reports from mouse or human models, whereas the response of three other transcripts (MT1E, NR4A1, PKP2) conflicted with previous reports. Overall, the results demonstrated a limited transcriptional response to PrPSc accumulation, when compared to microglia and macrophage cultures infected with other agents such as viruses and bacteria. This is the first microarray-based analysis of prion accumulation in primary cells derived from a natural TSE-host. Experiment Overall Design: Primary sheep microglial cells were either inoculated with PrPSc (Inoc) or sham-inoculated (Mock) Experiment Overall Design: Three biological replicates per treatment. Experiment Overall Design: Three technical replicates per biological replicate. Experiment Overall Design: biological replicate: Inoc12A, Inoc12B.2, Inoc12C Experiment Overall Design: biological replicate: Mock12A, Mock12B.2, Mock12C Experiment Overall Design: technical replicate - extract: Inoc12A.1, Inoc12A.2, Inoc12A.3 Experiment Overall Design: technical replicate - extract: Inoc12B.2.1, Inoc12B.2.2, Inoc12B.2.3 Experiment Overall Design: technical replicate - extract: Inoc12C.1, Inoc12C.2, Inoc12C.3 Experiment Overall Design: technical replicate - extract: Mock12A.1, Mock12A.2, Mock12A.3 Experiment Overall Design: technical replicate - extract: Mock12B.2.1, Mock12B.2.2, Mock12B.2.3 Experiment Overall Design: technical replicate - extract: Mock12C.1, Mock12C.2, Mock12C.3
Project description:Scrapie is a Transmissible Spongiform Encephalopathy (TSE) that affects sheep and goats and it is considered a good natural animal model to study prion diseases. Although changes in DNA methylation occur in many neurodegenerative diseases including human prion diseases, potential DNA methylation alterations have not yet been investigated in the central nervous system (CNS) of any prion disease models or naturally infected cases. We present here a whole genome bisulfite sequencing analysis (WGBS) from thalamus of four naturally scrapie infected sheep and four controls. All animals were female, carried the ARQ/ARQ genotype for the PRNP allele and were sacrificed at similar age (4 to 6 years old). Even if genomes displayed similar average methylation levels, we identified 39 differentially methylated promoters (DMP) and a total of 8,907 differentially methylated regions (DMR). Gene Ontology enrichment revealed that hypomethylated DMRs were enriched in genes involved in transmembrane transport and cell adhesion whereas hypermethylated DMRs were related with intracellular signal transduction genes. Moreover, we compared the set of identified DMRs with genes previously described to be differentially expressed in scrapie and with a set of genes encoding proteins defined to be tenfold more abundant in specific types of CNS cells finding that some of these genes also harboured DMRs. Finally, a validation study using qPCR was conducted showing differences in the expression of five genes (PCDH19, SNCG, WDR45B, PEX1 and CABIN1) that matched the methylation changes observed in the genomic study. Altogether, these findings suggest a potential regulatory role of CNS DNA methylation in prion diseases.
Project description:An essential and remarkable process of the biochemical and physiological features in prion diseases is the conversion of a host-encoded prion protein (PrPC) into a misfolded isoform (PrPSc). The conversion of PrPC and the replication of prions, in cases of peripheral infection, occur following the uptake and subsequent spread of prions to brain via spinal cord. We investigated the changes of gene expression profiles in the spleen, cervical spinal cord and thalamus following intraperitoneal inoculation of ME7 scrapie prion and the inter-tissue alterations of the differentially expressed genes through Venn diagram to find genes which are commonly influenced by ME7 scrapie prion spread in the three tissues.
Project description:In this study we identified genes differentially expressed in the central nervous system (CNS) of mice during infection with mouse-adapted scrapie agents. We used cDNA microarrays to examine gene expression profiles at early, mid (pre-clinical) and late (clinical) time points after inoculation. Keywords = scrapie Keywords = prion Keywords = CNS Keywords = BMAP Keywords: other
Project description:Prions cause transmissible neurodegenerative diseases and replicate by conformational conversion of normal, benign forms of prion protein (PrPC) to disease-causing PrPSc isoforms. A systems approach to disease postulates that disease arises from the pathological perturbation (genetic and/or environmental) of one or more biological networks in the relevant organ. In this regard, we tracked global (all mRNA transcripts) gene expression in the brains of eight distinct mouse strain-prion strain combinations at 8 - 10 time points throughout the progression of the disease to capture the effects of prion strain, host genetics, and PrP concentration on disease incubation time. Data are also available from http://prion.systemsbiology.net