Project description:Affymetrix genechip profiling analsysis (MOE430A and MOE430B) of murine neuroblastoma cells infected with either RML prion strain or mock brain homogenate Experiment Overall Design: Parental N2a cells were split into 6 aliquots, 3 of which were infected with RML prions and 3 of which were mock-infected with normal brain homogenate. There are three biological replicates in total for each experimental group.
Project description:While prion infections have been extensively characterized in the laboratory mouse, little is known regarding the molecular responses to prions in other rodents. To explore these responses and make comparisons, we generated a prion disease in the laboratory rat by successive passage of mouse RML prions. Here we describe the accumulation of prions and associated pathology in the rat and describe the transcriptional impact throughout prion disease. Comparative transcriptional profiling between laboratory mice and rats suggests that similar molecular processes are unfolding in response to prion infection. At the level of individual transcripts, however, variability exists between mice and rats and many genes deregulated in mouse scrapie are not affected in rats. Notwithstanding these differences, many transcriptome responses are conserved between mice and rats infected with scrapie. Our findings highlight the usefulness of comparative approaches to understanding neurodegeneration and prion diseases in particular. We Adapted RML Mouse Scrapie into Rats and measured the resulting gene expression changes in brain as a result of disease progression. Rats were infected by intracranial inoculation with prion isolates obtained by adaptation of mouse RML scrapie prions into rats. Brain samples were collected from third and fourth passage infected rats and age-matched controls at specified timepoints and gene expression profiles obtained. For each time point, 3 diseased and control brain samples were profiled.
Project description:Prion diseases are fatal neurodegenerative disorders that include bovine spongiform encephalopathy (BSE) and scrapie in animals and Creutzfeldt-Jakob disease (CJD) in humans. They are characterized by long incubation periods, variation in which is determined by many factors including genetic background. In some cases it is possible that incubation time may be directly correlated to the level of gene expression. In order to test this hypothesis we combined incubation time data from five different inbred lines of mice with quantitative gene expression profiling in normal brains and identified five genes with expression levels that correlate with incubation time. One of these genes, Hspa13 (Stch), is a member of the Hsp70 family of ATPase heat shock proteins which have been previously implicated in prion propagation. To test whether Hspa13 plays a causal role in determining the incubation period we tested two over-expressing mouse models. The Tc1 human chromosome 21 (Hsa21) transchromosomic mouse model of Down syndrome is trisomic for many Hsa21 genes including Hspa13 and following Chandler/RML prion inoculation shows a 4% reduction in incubation time. Furthermore, a transgenic model with eight fold over-expression of mouse Hspa13 exhibited highly significant reductions in incubation time of 16%, 15% and 7% following infection with Chandler/RML, ME7 and MRC2 prion strains respectively. These data further implicate Hsp70-like molecular chaperones in protein misfolding disorders such as prion disease.
Project description:Prion diseases are fatal neurodegenerative disorders that include bovine spongiform encephalopathy (BSE) and scrapie in animals and Creutzfeldt-Jakob disease (CJD) in humans. They are characterized by long incubation periods, variation in which is determined by many factors including genetic background. In some cases it is possible that incubation time may be directly correlated to the level of gene expression. In order to test this hypothesis we combined incubation time data from five different inbred lines of mice with quantitative gene expression profiling in normal brains and identified five genes with expression levels that correlate with incubation time. One of these genes, Hspa13 (Stch), is a member of the Hsp70 family of ATPase heat shock proteins which have been previously implicated in prion propagation. To test whether Hspa13 plays a causal role in determining the incubation period we tested two over-expressing mouse models. The Tc1 human chromosome 21 (Hsa21) transchromosomic mouse model of Down syndrome is trisomic for many Hsa21 genes including Hspa13 and following Chandler/RML prion inoculation shows a 4% reduction in incubation time. Furthermore, a transgenic model with eight fold over-expression of mouse Hspa13 exhibited highly significant reductions in incubation time of 16%, 15% and 7% following infection with Chandler/RML, ME7 and MRC2 prion strains respectively. These data further implicate Hsp70-like molecular chaperones in protein misfolding disorders such as prion disease. 5 inbred lines of mice, 5 samples for each line
Project description:Cultured organotypic cerebellar slices were exposed for different time points with either prions (RML) versus non-infectious brain homogenate (NBH) or ligands to the globular domain of the prion protein (POM1) vs IgG We used microarrays to characterize the temporal response of two inducers prion protein dependent cell death: COCS were exposed to RML prions or Non-infectious brain homogenate (NBH) and harvested after 14d, 25d, 38d and 45d (4 replicates each condition). COCS were exposed to POM1 or IgG and harvested after 8h, 1d, 3d, 7d, 10d (4 replicates each condition).
Project description:Prion infection in animals results in neurodegeneration and eventually death. To examine the cellular impact of Prion disease, we profiled non-proliferative fully differentiated C2C12 cells, which can replicate prions to high levels. Results suggest that accumulation of high levels of PrPSc in C2C12 myotubes does not cause any overt cellular dysfunction or molecular pathology. C2C12 cells were differentiated into confluent myotubes. Cells were infected or not with 100ul of 10% brain homogenate obtained from a C57BL/6 mouse clinically affected with RML prions. 16 days after infection, cells were collected by scraping and RML was purified.
Project description:Cultured organotypic cerebellar slices were exposed for different time points with either prions (RML) versus non-infectious brain homogenate (NBH) or ligands to the globular domain of the prion protein (POM1) vs IgG
Project description:Microglia, the resident macrophages of the brain parenchyma, are central players in CNS development, homeostasis and disorders. Distinct brain pathologies seem associated with discrete microglia activation modules. How microglia regain their ground state following challenges remains much less understood. Here, we explored the role of the IL-10 axis in restoring murine microglia homeostasis following peripheral endotoxin challenge. Specifically, we show that lipopolysaccharide (LPS)-challenged mice harboring IL-10 receptor-deficient microglia display neuronal impairment and succumb to fatal sickness. Addition of a microglial TNF deficiency rescues these animals, suggesting a microglia-based circuit driving pathology. Single cell transcriptome analysis revealed various IL-10 producing resident and recruited immune cell in the CNS, including most prominently Ly49D+ NK cells and neutrophils, but not microglia. Collectively, we define the kinetics of the microglia response to peripheral endotoxin challenge, including their activation and robust silencing, and highlight the critical role of non-microglial IL-10 in preventing deleterious microglia hyperactivation.