Preparation of soluble infectious samples from scrapie‐infected brain: a new tool to study the clearance of transmissible spongiform encephalopathy agents during plasma fractionation

Berardi, Vito Angelo; Cardone, Franco; Valanzano, Angela; Lu, Mengji; Pocchiari, Maurizio

doi:10.1111/j.1537-2995.2006.00763.x

Cited by 38 publications

(50 citation statements)

References 44 publications

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“…In contrast to the small infectious PrP res aggregates described here, the previously described small PrP aggregates are sensitive to PK digestion, and no evidence indicates that they can transmit disease (31,32). Small infectious PrP res aggregates, such as those described here, might give a molecular basis for the perplexing presence of infectivity in soluble preparations of infected hamster brain (33). Also, in a very recent study (10), density gradients were used to fractionate detergent-solubilized brain homogenate from tg338 mice infected with the ovine prion agent (PG127) used here.…”

Section: Discussioncontrasting

confidence: 43%

Recovery of Small Infectious PrPres Aggregates from Prion-infected Cultured Cells

Arellano-Anaya¹,

Savistchenko²,

Massonneau

et al. 2011

Journal of Biological Chemistry

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Prion diseases are characterized by deposits of abnormal conformers of the PrP protein. Although large aggregates of proteinase K-resistant PrP (PrP res ) are infectious, the precise relationships between aggregation state and infectivity remain to be established. In this study, we have fractionated detergent lysates from prion-infected cultured cells by differential ultracentrifugation and ultrafiltration and have characterized a previously unnoticed PrP species. This abnormal form is resistant to proteinase K digestion but, in contrast to typical aggregated PrP res , remains in the soluble fraction at intermediate centrifugal forces and is not retained by filters of 300-kDa cutoff. Cell-based assay and inoculation to animals demonstrate that these entities are infectious. The finding that cell-derived small infectious PrP res aggregates can be recovered in the absence of strong in vitro denaturating treatments now gives a biological basis for investigating the role of small PrP aggregates in the pathogenicity and/or the multiplication cycle of prions.Prion diseases are caused by the misfolding of the endogenously expressed PrP protein, and the most widely accepted model of prion multiplication is that abnormally folded PrP recruits and converts the host PrP into new abnormal forms (1-3). Historically, abnormal PrP was operationally defined as insoluble and resistant to protease digestion (4) and was subsequently termed PrP res . 4 Although normal PrP protein is soluble in detergents and sensitive to proteinase K (PK) digestion, part of PrP in infected tissues is PK-resistant and recovered in the pellets of centrifuged samples. These large PrP res aggregates are infectious (5), but it is unclear whether infectivity is entirely congruent with these species (6, 7) or whether they are the more efficient species to promote infection. Efficient transmission in the absence of detectable typical PrP res has been observed in some models of prion diseases (8, 9), and in other situations, infectivity and the bulk of large PrP res aggregates have distinct sedimentation profiles in density gradients (10). In addition, large aggregates of PrP res are not the only abnormal forms in diseased tissues, as exemplified by the characterization of PKsensitive abnormal forms of . Collectively, these and other findings (16) indicated that abnormal PrP is a set of diverse populations, displaying various biochemical properties and different morphological deposits in the brain, and their biological properties have yet to be established. Here, we investigated the diversity of infectious abnormal PrP species in a cell line and in neuronal primary cultures infected with a sheep scrapie agent. Although we obtained no evidence for the presence of PK-sensitive infectivity, we identified a previously unnoticed abnormal PrP species. Solubility and ultrafiltration assays indicate that these PK-resistant PrP entities are small aggregates. These species are infectious and may explain the perplexing presence of infectivity in brain samples devoid o...

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Section: Discussioncontrasting

confidence: 43%

Recovery of Small Infectious PrPres Aggregates from Prion-infected Cultured Cells

Arellano-Anaya¹,

Savistchenko²,

Massonneau

et al. 2011

Journal of Biological Chemistry

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“…It is nevertheless possible that limited muscle sampling and methodological insensitivity could fail to detect the irregular distribution of low levels of PrP TSE in muscle. Moreover, the absence of PrP TSE does not necessarily imply absence of infectivity (Barron et al, 2007;Berardi et al, 2006;Lasmézas et al, 1997). A more thorough examination of entire muscle groups using the ultrasensitive proteinmisfolding cyclic-amplification technique (Soto et al, 2005) might yield a positive result, but would need to be verified by infectivity bioassay before inferring a risk of disease transmission.…”

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confidence: 99%

PrPTSE in muscle-associated lymphatic tissue during the preclinical stage of mice infected orally with bovine spongiform encephalopathy

Cardone

Thomzig

Schulz‐Schaeffer

et al. 2009

Journal of General Virology

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The involvement of muscles in the pathogenesis of transmissible spongiform encephalopathies (TSEs) is irregular and unpredictable. We show that the TSE-specific protein (PrP TSE ) is present in muscles of mice fed with a mouse-adapted strain of bovine spongiform encephalopathy as early as 100 days post-infection, corresponding to about one-third of the incubation period. The proportion of mice with PrP TSE -positive muscles and the number of muscles involved increased as infection progressed, but never attained more than a limited distribution, even at the clinical stage of disease. The appearance of PrP TSE in muscles during the preclinical stage of disease was probably due to the haematogenous/lymphatic spread of infectivity from the gastrointestinal tract to lymphatic tissues associated with muscles, whereas in symptomatic animals, the presence of PrP TSE in the nervous system, in neuromuscular junctions and in muscle fibres suggests a centrifugal spread from the central nervous system, as already observed in other TSE models.

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“…The potential aims of nonimmune or drug treatment strategies for prion diseases overlap with the targets of immune therapies, including (1) decontamination of infectious sources, (2) prophylaxis against initial infections, (3) inhibition of peripheral propagation, (4) blockade of neuroinvasion, (5) inhibition of conversion to and accumulation of pathogenic PrP, (6) destabilization or enhanced clearance of pathogenic PrP, (7) blockade of direct or indirect neurotoxic effects of pathogenic PrP, and (8) compensation for damage to brain cells.…”

Section: Chemical-based Therapies and Prophylaxismentioning

confidence: 99%

Prion Disease Therapy: Trials and Tribulations

Sim

Caughey

2010

Protein Misfolding Diseases

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Preparation of soluble infectious samples from scrapie‐infected brain: a new tool to study the clearance of transmissible spongiform encephalopathy agents during plasma fractionation

Cited by 38 publications

References 44 publications

Recovery of Small Infectious PrPres Aggregates from Prion-infected Cultured Cells

Recovery of Small Infectious PrPres Aggregates from Prion-infected Cultured Cells

PrPTSE in muscle-associated lymphatic tissue during the preclinical stage of mice infected orally with bovine spongiform encephalopathy

Prion Disease Therapy: Trials and Tribulations

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