| 1. |
- Falsig, Jeppe, et al.
(författare)
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Chemical and biophysical insights into the propagation of prion strains
- 2008
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Ingår i: HFSP JOURNAL. - : Informa UK Limited. - 1955-2068. ; 2:6, s. 332-341
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Tidskriftsartikel (refereegranskat)abstract
- Transmissible spongiform encephalopathies (TSEs) are lethal infectious neurodegenerative diseases. TSEs are caused by prions, infectious agents lacking informational nucleic acids, and possibly identical with higher-order aggregates of the cellular glycolipoprotein PrPC. Prion strains are derived from TSE isolates that, even after inoculation into genetically identical hosts, cause disease with distinct patterns of protein aggregate deposition, incubation times, morphology of the characteristic brain damage, and cellular tropism. Most of these traits are relatively stable across serial passages. Here we review current techniques for studying prion strain differences in vivo and in cells, and discuss the strain phenomena in the general context of the knowledge gained from modeling prion fibril growth in vitro and in simple organisms.
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| 2. |
- Lund, Sören, et al.
(författare)
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The dynamics of the LPS triggered inflammatory response of murine microglia under different culture and in vivo conditions
- 2006
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Ingår i: J Neuroimmunol. ; 180:1-2, s. 71-87
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Tidskriftsartikel (refereegranskat)abstract
- Overall, the inflammatory potential of lipopolysaccharide (LPS) in vitro and in vivo was investigated using different omics technologies. We investigated the hippocampal response to intracerebroventricular (i.c.v) LPS in vivo, at both the transcriptional and protein level. Here, a time course analysis of interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1) showed a sharp peak at 4 h and a return to baseline at 16 h. The expression of inflammatory mediators was not temporally correlated with expression of the microglia marker F4/80, which did not peak until 2 days after LPS injection. Of 480 inflammation-related genes present on a microarray, 29 transcripts were robustly up-regulated and 90% of them were also detected in LPS stimulated primary microglia (PM) cultures. Further in vitro to in vivo comparison showed that the counter regulation response observed in vivo was less evident in vitro, as transcript levels in PM decreased relatively little over 16 h. This apparent deficiency of homeostatic control of the innate immune response in cultures may also explain why a group of genes comprising tnf receptor associated factor-1, endothelin-1 and schlafen-1 were regulated strongly in vitro, but not in vivo. When the overall LPS-induced transcriptional response of PM was examined on a large Affymetrix chip, chemokines and cytokines constituted the most strongly regulated and largest groups. Interesting new microglia markers included interferon-induced protein with tetratricopeptide repeat (ifit), immune responsive gene-1 (irg-1) and thymidylate kinase family LPS-inducible member (tyki). The regulation of the former two was confirmed on the protein level in a proteomics study. Furthermore, conspicuous regulation of several gene clusters was identified, for instance that of genes pertaining to the extra-cellular matrix and enzymatic regulation thereof. Although most inflammatory genes induced in vitro were transferable to our in vivo model, the observed discrepancy for some genes potentially represents regulatory factors present in the central nervous system (CNS) but not in vitro.
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| 3. |
- Margalith, Ilan, et al.
(författare)
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Polythiophenes Inhibit Prion Propagation by Stabilizing Prion Protein (PrP) Aggregates
- 2012
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Ingår i: Journal of Biological Chemistry. - : American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 287:23, s. 18872-18887
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Tidskriftsartikel (refereegranskat)abstract
- Luminescent conjugated polymers (LCPs) interact with ordered protein aggregates and sensitively detect amyloids of many different proteins, suggesting that they may possess antiprion properties. Here, we show that a variety of anionic, cationic, and zwitterionic LCPs reduced the infectivity of prion-containing brain homogenates and of prion-infected cerebellar organotypic cultured slices and decreased the amount of scrapie isoform of PrPC (PrPSc) oligomers that could be captured in an avidity assay. Paradoxically, treatment enhanced the resistance of PrPSc to proteolysis, triggered the compaction, and enhanced the resistance to proteolysis of recombinant mouse PrP(23-231) fibers. These results suggest that LCPs act as antiprion agents by transitioning PrP aggregates into structures with reduced frangibility. Moreover, ELISA on cerebellar organotypic cultured slices and in vitro conversion assays with mouse PrP(23-231) indicated that poly(thiophene-3-acetic acid) may additionally interfere with the generation of PrPSc by stabilizing the conformation of PrPC or of a transition intermediate. Therefore, LCPs represent a novel class of antiprion agents whose mode of action appears to rely on hyperstabilization, rather than destabilization, of PrPSc deposits.
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| 4. |
- Sigurdson, Christina J, et al.
(författare)
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De novo generation of a transmissible spongiform encephalopathy by mouse transgenesis.
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:1, s. 304-309
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Tidskriftsartikel (refereegranskat)abstract
- Most transmissible spongiform encephalopathies arise either spontaneously or by infection. Mutations of PRNP, which encodes the prion protein, PrP, segregate with phenotypically similar diseases. Here we report that moderate overexpression in transgenic mice of mPrP(170N,174T), a mouse PrP with two point mutations that subtly affect the structure of its globular domain, causes a fully penetrant lethal spongiform encephalopathy with cerebral PrP plaques. This genetic disease was reproduced with 100% attack rate by intracerebral inoculation of brain homogenate to tga20 mice overexpressing WT PrP, and from the latter to WT mice, but not to PrP-deficient mice. Upon successive transmissions, the incubation periods decreased and PrP became more protease-resistant, indicating the presence of a strain barrier that was gradually overcome by repeated passaging. This shows that expression of a subtly altered prion protein, with known 3D structure, efficiently generates a prion disease.
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