scholarly journals Characterization and polyanion-binding properties of purified recombinant prion protein

1999 ◽  
Vol 342 (3) ◽  
pp. 605-613 ◽  
Author(s):  
Debbie B. BRIMACOMBE ◽  
Alan D. BENNETT ◽  
Fred S. WUSTEMAN ◽  
Andrew C. GILL ◽  
Janine C. DANN ◽  
...  
Keyword(s):  
Prion Protein ◽  
Mammalian Cells ◽  
Metal Ion ◽  
Transmissible Spongiform Encephalopathy ◽  
Spongiform Encephalopathy ◽  
Divalent Metal Ions ◽  
Dissociation Kinetics ◽  
Recombinant Prion Protein

Certain polysulphated polyanions have been shown to have prophylactic effects on the progression of transmissible spongiform encephalopathy disease, presumably because they bind to prion protein (PrP). Until now, the difficulty of obtaining large quantities of native PrP has precluded detailed studies of these interactions. We have over-expressed murine recombinant PrP (recPrP), lacking its glycophosphoinositol membrane anchor, in modified mammalian cells. Milligram quantities of secreted, soluble and partially glycosylated protein were purified under non-denaturing conditions and the identities of mature-length aglycosyl recPrP and two cleavage fragments were determined by electrospray MS. Binding was assessed by surface plasmon resonance techniques using both direct and competitive ligand-binding approaches. recPrP binding to immobilized polyanions was enhanced by divalent metal ions. Polyanion binding was strong and showed complex association and dissociation kinetics that were consistent with ligand-directed recPrP aggregation. The differences in the binding strengths of recPrP to pentosan polysulphate and to other sulphated polyanions were found to parallel their in vivo anti-scrapie and in vitro anti-scrapie-specific PrP formation potencies. When recPrP was immobilized by capture on metal-ion chelates it was found, contrary to expectation, that the addition of polyanions promoted the dissociation of the protein.

scholarly journals PrP P102L and Nearby Lysine Mutations Promote Spontaneous In Vitro Formation of Transmissible Prions

2017 ◽  
Vol 91 (21) ◽  
Author(s):  
Allison Kraus ◽  
Gregory J. Raymond ◽  
Brent Race ◽  
Katrina J. Campbell ◽  
Andrew G. Hughson ◽  
...  
Keyword(s):  
Prion Protein ◽  
Prion Diseases ◽  
Transmissible Spongiform Encephalopathy ◽  
Clinical Signs ◽  
Protein Aggregates ◽  
Structural Features ◽  
Spongiform Encephalopathy ◽  
Specific Sequence

ABSTRACT Accumulation of fibrillar protein aggregates is a hallmark of many diseases. While numerous proteins form fibrils by prion-like seeded polymerization in vitro, only some are transmissible and pathogenic in vivo. To probe the structural features that confer transmissibility to prion protein (PrP) fibrils, we have analyzed synthetic PrP amyloids with or without the human prion disease-associated P102L mutation. The formation of infectious prions from PrP molecules in vitro has required cofactors and/or unphysiological denaturing conditions. Here, we demonstrate that, under physiologically compatible conditions without cofactors, the P102L mutation in recombinant hamster PrP promoted prion formation when seeded by minute amounts of scrapie prions in vitro. Surprisingly, combination of the P102L mutation with charge-neutralizing substitutions of four nearby lysines promoted spontaneous prion formation. When inoculated into hamsters, both of these types of synthetic prions initiated substantial accumulation of prion seeding activity and protease-resistant PrP without transmissible spongiform encephalopathy (TSE) clinical signs or notable glial activation. Our evidence suggests that PrP's centrally located proline and lysine residues act as conformational switches in the in vitro formation of transmissible PrP amyloids. IMPORTANCE Many diseases involve the damaging accumulation of specific misfolded proteins in thread-like aggregates. These threads (fibrils) are capable of growing on the ends by seeding the refolding and incorporation of the normal form of the given protein. In many cases such aggregates can be infectious and propagate like prions when transmitted from one individual host to another. Some transmitted aggregates can cause fatal disease, as with human iatrogenic prion diseases, while other aggregates appear to be relatively innocuous. The factors that distinguish infectious and pathogenic protein aggregates from more innocuous ones are poorly understood. Here we have compared the combined effects of prion seeding and mutations of prion protein (PrP) on the structure and transmission properties of synthetic PrP aggregates. Our results highlight the influence of specific sequence features in the normally unstructured region of PrP that influence the infectious and neuropathogenic properties of PrP-derived aggregates.

scholarly journals Inhibition of Protease-Resistant Prion Protein Accumulation In Vitro by Curcumin

2003 ◽  
Vol 77 (9) ◽  
pp. 5499-5502 ◽  
Author(s):  
Byron Caughey ◽  
Lynne D. Raymond ◽  
Gregory J. Raymond ◽  
Laura Maxson ◽  
Jay Silveira ◽  
...  
Keyword(s):  
Prion Protein ◽  
Inhibitory Concentration ◽  
Transmissible Spongiform Encephalopathy ◽  
Neuroblastoma Cells ◽  
In Vivo Studies ◽  
Spongiform Encephalopathy ◽  
Protein Accumulation ◽  
The Brain

ABSTRACT Inhibition of the accumulation of protease-resistant prion protein (PrP-res) is a prime strategy in the development of potential transmissible spongiform encephalopathy (TSE) therapeutics. Here we show that curcumin (diferoylmethane), a major component of the spice turmeric, potently inhibits PrP-res accumulation in scrapie agent-infected neuroblastoma cells (50% inhibitory concentration, ∼10 nM) and partially inhibits the cell-free conversion of PrP to PrP-res. In vivo studies showed that dietary administration of curcumin had no significant effect on the onset of scrapie in hamsters. Nonetheless, other studies have shown that curcumin is nontoxic and can penetrate the brain, properties that give curcumin advantages over inhibitors previously identified as potential prophylactic and/or therapeutic anti-TSE compounds.

scholarly journals Evaluation of Quinacrine Treatment for Prion Diseases

2003 ◽  
Vol 77 (15) ◽  
pp. 8462-8469 ◽  
Author(s):  
A. Barret ◽  
F. Tagliavini ◽  
G. Forloni ◽  
C. Bate ◽  
M. Salmona ◽  
...  
Keyword(s):  
Prion Protein ◽  
De Novo ◽  
Neuroblastoma Cells ◽  
Animal Origin ◽  
Detectable Effect ◽  
Spongiform Encephalopathy ◽  
Protease Resistance ◽  
New Variant

ABSTRACT Based on in vitro observations in scrapie-infected neuroblastoma cells, quinacrine has recently been proposed as a treatment for Creutzfeldt-Jakob disease (CJD), including a new variant CJD which is linked to contamination of food by the bovine spongiform encephalopathy (BSE) agent. The present study investigated possible mechanisms of action of quinacrine on prions. The ability of quinacrine to interact with and to reduce the protease resistance of PrP peptide aggregates and PrPres of human and animal origin were analyzed, together with its ability to inhibit the in vitro conversion of the normal prion protein (PrPc) to the abnormal form (PrPres). Furthermore, the efficiencies of quinacrine and chlorpromazine, another tricyclic compound, were examined in different in vitro models and in an experimental murine model of BSE. Quinacrine efficiently hampered de novo generation of fibrillogenic prion protein and PrPres accumulation in ScN2a cells. However, it was unable to affect the protease resistance of preexisting PrP fibrils and PrPres from brain homogenates, and a “curing” effect was obtained in ScGT1 cells only after lengthy treatment. In vivo, no detectable effect was observed in the animal model used, consistent with other recent studies and preliminary observations in humans. Despite its ability to cross the blood-brain barrier, the use of quinacrine for the treatment of CJD is questionable, at least as a monotherapy. The multistep experimental approach employed here could be used to test new therapeutic regimes before their use in human trials.

scholarly journals Synergistic and strain-specific effects of bovine spongiform encephalopathy and scrapie prions in the cell-free conversion of recombinant prion protein

2006 ◽  
Vol 87 (12) ◽  
pp. 3753-3761 ◽  
Author(s):  
Martin Eiden ◽  
Gottfried J. Palm ◽  
Winfried Hinrichs ◽  
Ulrich Matthey ◽  
Ralph Zahn ◽  
...  
Keyword(s):  
Bovine Spongiform Encephalopathy ◽  
Prion Protein ◽  
De Novo ◽  
Proteinase K ◽  
Spongiform Encephalopathy ◽  
Cooperative Action ◽  
Specific Effects ◽  
Scrapie Strains ◽  
Recombinant Prion Protein

This study describes the conversion of murine PrPC by PrPSc from three different mouse scrapie strains (ME7, 87V and 22A) and from a mouse-passaged bovine spongiform encephalopathy (BSE) strain (BSE/Bl6). This was demonstrated by a modified, non-radioactive, cell-free conversion assay using bacterial prion protein, which was converted into a proteinase K (PK)-resistant fragment designated PrPres. Using this assay, newly formed PrPres could be detected by an antibody that discriminated de novo PrPres and the original PrPSc seed. The results suggested that PrPres formation occurs in three phases: the first 48 h when PrPres formation is delayed, followed by a period of substantially accelerated PrPres formation and a plateau phase when a maximum concentration of PrPres is reached after 72 h. The conversion of prokaryotically expressed PrPC by ME7 and BSE prions led to unglycosylated, PK-digested, abnormal PrPres fragments, which differed in molecular mass by 1 kDa. Therefore, prion strain phenotypes were retained in the cell-free conversion, even when recombinant PrPC was used as the substrate. Moreover, co-incubation of ME7 and BSE prions resulted in equal amounts of both ME7- and BSE-derived PrPres fragments (as distinguished by their different molecular sizes) and also in a significantly increased total amount of de novo-generated PrPres. This was found to be more than twice the amount of either strain when incubated separately. This result indicates a synergistic effect of both strains during cell-free conversion. It is not yet known whether such a cooperative action between BSE and scrapie prions also occurs in vivo.

Factors affecting interactions between prion protein isoforms

2002 ◽  
Vol 30 (4) ◽  
pp. 565-569 ◽  
Author(s):  
B. Caughey ◽  
G. S. Baron
Keyword(s):  
Prion Protein ◽  
Recipient Cell ◽  
Transmissible Spongiform Encephalopathy ◽  
Heparan Sulphate ◽  
Protein Isoforms ◽  
Spongiform Encephalopathy ◽  
Factors Affecting ◽  
C Terminus ◽  
Low Concentrations

Interactions between normal, protease-sensitive prion protein (PrP-sen or PrPc) and its protease-resistant isoform (PrP-res or PrPsc) are critical in transmissible spongiform encephalopathy (TSE) diseases. To investigate the propagation of PrP-res between cells we tested whether PrP-res in scrapie brain microsomes can induce the conversion of PrP-sen to PrP-res if the PrP-sen is bound to uninfected raft membranes. Surprisingly, no conversion was observed unless the microsomal and raft membranes were fused or PrP-sen was released from raft membranes. These results suggest that the propagation of infection between cells requires transfer of PrP-res into the membranes of the recipient cell. To assess potential cofactors in PrP conversion, we used cell-free PrP conversion assays to show that heparan sulphate can stimulate PrP-res formation, supporting the idea that endogenous sulphated glycosaminoglycans can act as important cofactors or modulators of PrP-res formation in vivo. In an effort to develop therapeutics, the antimalarial drug quinacrine was identified as an inhibitor of PrP-res formation in scrapie-infected cell cultures. Confirmation of the latter result by others has led to the initiation of human clinical trials as a treatment for Creutzfeldt-Jakob disease. PrP-res formation can also be inhibited using a variety of other types of small molecule, specific synthetic PrP peptides, and an antiserum directed at the C-terminus of PrP-sen. The latter results help to localize the sites of interaction between PrP-sen and PrP-res. Disruption of those interactions with antibodies or peptidomimetic drugs may be an attractive therapeutic strategy. The likelihood that PrP-res inhibitors can rid TSE-infected tissues of PrP-res would presumably be enhanced if PrP-res formation were reversible. However, our attempts to measure dissociation of PrP-sen from PrP-res have failed under non-denaturing conditions. Finally, we have attempted to induce the spontaneous conversion of PrP-sen into PrP-res using low concentrations of detergents. A conformational conversion from α-helical monomers into high-β-sheet aggregates and fibrils was induced by low concentrations of the detergent sarkosyl; however, the aggregates had neither infectivity nor the characteristic protease-resistance of PrP-res.

scholarly journals Inhibition of Protease-Resistant Prion Protein Formation in a Transformed Deer Cell Line Infected with Chronic Wasting Disease

2006 ◽  
Vol 80 (2) ◽  
pp. 596-604 ◽  
Author(s):  
Gregory J. Raymond ◽  
Emily A. Olsen ◽  
Kil Sun Lee ◽  
Lynne D. Raymond ◽  
P. Kruger Bryant ◽  
...  
Keyword(s):  
Cell Line ◽  
Prion Protein ◽  
Chronic Wasting Disease ◽  
Transmissible Spongiform Encephalopathy ◽  
Mule Deer ◽  
Simian Virus 40 ◽  
Spongiform Encephalopathy ◽  
Wasting Disease ◽  
Neuronal Marker

ABSTRACT Chronic wasting disease (CWD) is an emerging transmissible spongiform encephalopathy (prion disease) of North American cervids, i.e., mule deer, white-tailed deer, and elk (wapiti). To facilitate in vitro studies of CWD, we have developed a transformed deer cell line that is persistently infected with CWD. Primary cultures derived from uninfected mule deer brain tissue were transformed by transfection with a plasmid containing the simian virus 40 genome. A transformed cell line (MDB) was exposed to microsomes prepared from the brainstem of a CWD-affected mule deer. CWD-associated, protease-resistant prion protein (PrPCWD) was used as an indicator of CWD infection. Although no PrPCWD was detected in any of these cultures after two passes, dilution cloning of cells yielded one PrPCWD-positive clone out of 51. This clone, designated MDBCWD, has maintained stable PrPCWD production through 32 serial passes thus far. A second round of dilution cloning yielded 20 PrPCWD-positive subclones out of 30, one of which was designated MDBCWD2. The MDBCWD2 cell line was positive for fibronectin and negative for microtubule-associated protein 2 (a neuronal marker) and glial fibrillary acidic protein (an activated astrocyte marker), consistent with derivation from brain fibroblasts (e.g., meningeal fibroblasts). Two inhibitors of rodent scrapie protease-resistant PrP accumulation, pentosan polysulfate and a porphyrin compound, indium (III) meso-tetra(4-sulfonatophenyl)porphine chloride, potently blocked PrPCWD accumulation in MDBCWD cells. This demonstrates the utility of these cells in a rapid in vitro screening assay for PrPCWD inhibitors and suggests that these compounds have potential to be active against CWD in vivo.

scholarly journals Molecular Profiling of Ovine Prion Diseases by Using Thermolysin-Resistant PrPSc and Endogenous C2 PrP Fragments

2007 ◽  
Vol 81 (19) ◽  
pp. 10532-10539 ◽  
Author(s):  
Jonathan P. Owen ◽  
Helen C. Rees ◽  
Ben C. Maddison ◽  
Linda A. Terry ◽  
Leigh Thorne ◽  
...  
Keyword(s):  
Prion Diseases ◽  
Transmissible Spongiform Encephalopathy ◽  
Spongiform Encephalopathy ◽  
Western Blots ◽  
Sheep Population ◽  
Natural Scrapie ◽  
Caudal Medulla ◽  
Scrapie Strains

ABSTRACT Disease-associated PrP fragments produced upon in vitro or in vivo proteolysis can provide significant insight into the causal strain of prion disease. Here we describe a novel molecular strain typing assay that used thermolysin digestion of caudal medulla samples to produce PrPres signatures on Western blots that readily distinguished experimental sheep bovine spongiform encephalopathy (BSE) from classical scrapie. Furthermore, the accumulation of such PrPres species within the cerebellum also appeared to be dependent upon the transmissible spongiform encephalopathy (TSE) strain, allowing discrimination between two experimental strains of scrapie and grouping of natural scrapie isolates into two profiles. The occurrence of endogenously produced PrP fragments, namely, glycosylated and unglycosylated C2, within different central nervous system (CNS) regions is also described; this is the first detailed description of such scrapie-associated fragments within a natural host. The advent of C2 fragments within defined CNS regions, compared between BSE and scrapie cases and also between two experimental scrapie strains, appeared to be largely dependent upon the TSE strain. The combined analyses of C2 fragments and thermolysin-resistant PrP species within caudal medulla, cerebellum, and spinal cord samples allowed natural scrapie isolates to be separated into four distinct molecular profiles: most isolates produced C2 and PrPres in all CNS regions, a second group lacked detectable cerebellar C2 fragments, one isolate lacked both cerebellar PrPres and C2, and a further isolate lacked detectable C2 within all three CNS regions and also lacked cerebellar PrPres. This CNS region-specific deposition of disease-associated PrP species may reflect the natural heterogeneity of scrapie strains in the sheep population in the United Kingdom.

scholarly journals Cellular prion protein status in sheep: tissue-specific biochemical signatures

2001 ◽  
Vol 82 (8) ◽  
pp. 2017-2024 ◽  
Author(s):  
Mohammed Moudjou ◽  
Yveline Frobert ◽  
Jacques Grassi ◽  
Claude La Bonnardière
Keyword(s):  
Skeletal Muscle ◽  
Prion Protein ◽  
Transmissible Spongiform Encephalopathy ◽  
Cellular Prion Protein ◽  
Spongiform Encephalopathy ◽  
Tissue Specific ◽  
Protein Status ◽  
Low Levels ◽  
Recombinant Prion Protein ◽  
The Brain

Expression of the cellular prion protein PrPC is sine qua none for the development of transmissible spongiform encephalopathy and thus for the accumulation of the illness-associated conformer PrPSc. Therefore, the tissue distribution of PrPC at the protein level in both quantitative and qualitative terms was investigated. PrPC was quantified using a two-site enzyme immunometric assay which was calibrated with purified ovine recombinant prion protein (rPrP). The most PrPC-rich tissue was the brain, followed by the lungs, skeletal muscle, heart, uterus, thymus and tongue, which contained between 20- and 50-fold less PrPC than the brain. The PrPC content of these tissues seems to be comparable between sheep. Other organs, however, showed different, but low, levels of the protein depending on the animal examined. This was also the case for tissues from the gastrointestinal tract. The tissue containing the lowest concentration of PrPC was shown to be the liver, where PrPC was found to be between 564- and 16000-fold less abundant than in the brain. PrPC was concentrated from crude cellular extracts by immunoprecipitation using several monoclonal and polyclonal anti-ovine PrP antibodies. Interestingly, it was observed that the isoform profile of PrPC was tissue-specific. The most atypical electrophoretic profile of PrPC was found in the skeletal muscle, where two polypeptides of 32 and 35 kDa were detected.

scholarly journals A reassessment of copper(II) binding in the full-length prion protein

2006 ◽  
Vol 399 (3) ◽  
pp. 435-444 ◽  
Author(s):  
Mark A. Wells ◽  
Graham S. Jackson ◽  
Samantha Jones ◽  
Laszlo L. P. Hosszu ◽  
C. Jeremy Craven ◽  
...  
Keyword(s):  
Prion Protein ◽  
Metal Ion ◽  
Tandem Repeats ◽  
Binding Mode ◽  
Full Length ◽  
Alternative Mode ◽  
Histidine Residues ◽  
Terminal Domain

It has been shown previously that the unfolded N-terminal domain of the prion protein can bind up to six Cu2+ ions in vitro. This domain contains four tandem repeats of the octapeptide sequence PHGGGWGQ, which, alongside the two histidine residues at positions 96 and 111, contribute to its Cu2+ binding properties. At the maximum metal-ion occupancy each Cu2+ is co-ordinated by a single imidazole and deprotonated backbone amide groups. However two recent studies of peptides representing the octapeptide repeat region of the protein have shown, that at low Cu2+ availability, an alternative mode of co-ordination occurs where the metal ion is bound by multiple histidine imidazole groups. Both modes of binding are readily populated at pH 7.4, while mild acidification to pH 5.5 selects in favour of the low occupancy, multiple imidazole binding mode. We have used NMR to resolve how Cu2+ binds to the full-length prion protein under mildly acidic conditions where multiple histidine co-ordination is dominant. We show that at pH 5.5 the protein binds two Cu2+ ions, and that all six histidine residues of the unfolded N-terminal domain and the N-terminal amine act as ligands. These two sites are of sufficient affinity to be maintained in the presence of millimolar concentrations of competing exogenous histidine. A previously unknown interaction between the N-terminal domain and a site on the C-terminal domain becomes apparent when the protein is loaded with Cu2+. Furthermore, the data reveal that sub-stoichiometric quantities of Cu2+ will cause self-association of the prion protein in vitro, suggesting that Cu2+ may play a role in controlling oligomerization in vivo.

Prion protein as a target for therapeutic interventions

2004 ◽  
Vol 76 (5) ◽  
pp. 915-920 ◽  
Author(s):  
P. P. Liberski
Keyword(s):  
Prion Protein ◽  
Phenotypic Expression ◽  
Therapeutic Interventions ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Public Health Perspective ◽  
Spongiform Encephalopathies ◽  
Mad Cow Disease

Transmissible spongiform encephalopathies (TSEs), currently known as prion diseases, are neurodegenerative disorders of the central nervous system (CNS) caused by an elusive infectious agent called “prion” (proteinaceous infectious particle). These dis orders include: kuru, Creutzfeldt –Jakob disease (CJD) and its variant (vCJD), Gerstmann–Sträussler–Scheinker (GSS) disease and fatal familial insomnia (FFI) in humans, scrapie in sheep and goats, bovine spongiform encephalopathy (BSE) or mad cow disease, and chronic wasting disease (CWD) in cervids. According to the widely accepted “prion hypothesis”, prion is an aggregate of the abnormal isoform of prion protein (PrPSc). Prion protein is a cell-derived glycoprotein (this normal isoform is called PrPc) encoded by a gene on chromosome 20 in humans (PRNP). In familial forms of TSEs, mutations within the ORF of PRNP are linked to the phenotypic expression of the disease. TSEs are important from public health perspective, and “mad cow disease has created the greatest threat to the safety of human food supply in modern times. vCJD threatens the safety of the blood supply worldwide”. Thus, to search for effective therapy is more than an urgent task. In TSEs, aggregates of PrPSc accumulate in the brain in a form of plaques, or synaptic deposits. The conversion of PrPc into PrPSc and subsequent deposits of PrPSc are targets for therapeutic interventions. These include: tricyclic compounds—acridine and phenothiazine derivatives; quinacrine; anti-PrPSc antibodies; dendrimers; polyethylene antibiotics (amphotericin B, MS-8209); pentosan polysulfate; and dextran sulfate. All these compounds are active in many in vitro and in vivo assays, but not proved definitely active in humans. Thus, albeit interesting and promising, the chemotherapy of TSEs is still in the infant phase.

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