Possible origin of the scrapie genome in small endogenous RNAs; studies on eight candidate species in 263K scrapie-infected hamster brain

2019 ◽  
Author(s):  
Eleanor Barnard ◽  
Kathryn Estibeiro ◽  
Rory Duncan ◽  
Janet Baird ◽  
David Fettes ◽  
...  
Keyword(s):  
Infectious Agent ◽  
Etiologic Agent ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Systematic Analysis ◽  
Spongiform Encephalopathies ◽  
Rna Molecules ◽  
Infected Hamster ◽  
Molecular Variants ◽  
Initial Work

SUMMARYThe identity of the etiologic agent of the transmissible spongiform encephalopathies (TSEs), including bovine spongiform encephalopathy (BSE), scrapie and Creutzfeldt-Jakob disease (CJD), remains unknown. While much attention has been given to the hypothesis that the TSEs may be caused by a proteinaceous infectious agent or ‘prion’, there is considerable evidence to suggest that this hypothesis is incomplete. We have pursued an alternative contention: that the etiologic agent comprises in part a modified and replicating form of an endogenous nucleic acid, probably RNA. The ‘endovirus’ hypothesis contends that the parental molecule is most likely to be a small and highly-structured cellular RNA that can convert to a replicating molecule by a finite number of nucleotide sequence changes. We have begun a systematic analysis of candidate molecular species present in hamster brain infected with scrapie strain 263K. Initial work focussed on the 7S group of small RNAs. Examination of 7-2, 7SK and 7SL failed to reveal differences in abundance and/or sequence between normal and scrapie (263K)-infected hamster brain. Inspection of other possible candidates, including U3, H1/8-2 and novel molecules KR1, nu1 and nu2, similarly failed to provide evidence for scrapie-specific molecular variants; alterations to the KR1 sequence failed to correlate with disease. We present sequences of hamster RNAs 7-2, 7SK, 7SL, H1/8-2, U3, nu1, nu2 and KR1. Together our data so far fail to contradict or confirm the hypothesis, while arguing that the major species of these 8 RNA molecules are unlikely to correspond to the etiologic agent of the TSEs.

scholarly journals Sympathetic Prions

2001 ◽  
Vol 1 ◽  
pp. 555-556 ◽  
Author(s):  
Markus Glatzel
Keyword(s):  
Gastrointestinal Tract ◽  
Injection Site ◽  
Peripheral Nerves ◽  
Infectious Agent ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Membrane Glycoprotein ◽  
Spongiform Encephalopathies ◽  
Jakob Disease ◽  
The Brain

Transmissible spongiform encephalopathies are a group of invariably fatal neurodegenerative diseases. The infectious agent is termed prion and is thought to be composed of a modified protein (PrPSc or PrPRES), a protease-resistant conformer of the normal host-encoded membrane glycoprotein, PrPC[1]. Bovine spongiform encephalopathy, scrapie of sheep, and Creutzfeldt-Jakob disease are among the most notable transmissible spongiform encephalopathies. Prions are most efficiently propagated trough intracerebral inoculation, yet the entry point of the infectious agent is often through peripheral sites like the gastrointestinal tract[2,3]. The process by which prions invade the brain is termed neuroinvasion[4]. We and others have speculated that, depending on the amount of infectious agent injected, the injection site, and the strain of prions employed, neuroinvasion can occur either directly via peripheral nerves or first through the lymphoreticular system and then via peripheral nerves[5].

scholarly journals Characterization of the effect of heat on agent strains of the transmissible spongiform encephalopathies

2011 ◽  
Vol 92 (7) ◽  
pp. 1738-1748 ◽  
Author(s):  
Robert A. Somerville ◽  
Nicola Gentles
Keyword(s):  
Conformational Changes ◽  
High Resistance ◽  
Thermal Inactivation ◽  
Transmissible Spongiform Encephalopathy ◽  
Infectious Agent ◽  
Host Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Heat Inactivation ◽  
Spongiform Encephalopathy ◽  
Spongiform Encephalopathies

The causal agents of the transmissible spongiform encephalopathy (TSE) diseases, sometimes called prion diseases, are characterized by high resistance to inactivation with heat. Results from thermal inactivation experiments on nine TSE strains, seven passaged in two PrP genotypes, showed differences in sensitivity to heat inactivation ranging over 17 °C. In addition, the rate of inactivation with increasing temperature varied between TSE models. In some cases passage in an alternative PrP genotype had little effect on the resulting inactivation properties, but for others the infectious agent was inactivated at lower temperatures. No strain with higher thermostability properties was selected. The effect of mixing two TSE strains, to see whether their properties were affected through interaction with each other, was also examined. The results showed that both strains behaved as expected from the behaviour of the unmixed controls, and that the strain responsible for inducing TSE disease could be identified. There was no evidence of a direct effect on intrinsic strain properties. Overall, the results illustrate the diversity in properties of TSE strains. They require intrinsic molecular properties of TSE agents to accommodate high resistance to inactivation and a mechanism, independent of the host, to directly encode these differences. These findings are more readily reconciled with models of TSE agents with two separate components, one of which is independent of the host and comprises a TSE-specific nucleic acid, than with models based solely on conformational changes to a host protein.

scholarly journals Transmissible spongiform encephalopathy strain, PrP genotype and brain region all affect the degree of glycosylation of PrPSc

2005 ◽  
Vol 86 (1) ◽  
pp. 241-246 ◽  
Author(s):  
Robert A. Somerville ◽  
Scott Hamilton ◽  
Karen Fernie
Keyword(s):  
Prion Diseases ◽  
Transmissible Spongiform Encephalopathy ◽  
Infectious Agent ◽  
Host Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Major Influence ◽  
Spongiform Encephalopathy ◽  
Phenotypic Properties ◽  
Spongiform Encephalopathies ◽  
Diagnostic Potential

Transmissible spongiform encephalopathies (TSEs), sometimes known as prion diseases, are caused by an infectious agent whose molecular properties have not been determined. Traditionally, different strains of TSE diseases are characterized by a series of phenotypic properties after passage in experimental animals. More recently it has been recognized that diversity in the degree to which an abnormal form of the host protein PrP, denoted PrPSc, is glycosylated and the migration of aglycosyl forms of PrPSc on immunoblots may have some differential diagnostic potential. It has been recognized that these factors are affected by the strain of TSE agent but also by other factors, e.g. location within the brain. This study shows in some cases, but not others, that host PrP genotype has a major influence on the degree of PrPSc glycosylation and migration on gels and provides further evidence of the effect of brain location. Accordingly both the degree of glycosylation and the apparent molecular mass of PrPSc may be of some value for differential diagnosis between TSE strains, but only when host effects are taken into account. Furthermore, the data inform the debate about how these differences arise, and favour hypotheses proposing that TSE agents affect glycosylation of PrP during its biosynthesis.

An overview of transmissible spongiform encephalopathies

2004 ◽  
Vol 5 (2) ◽  
pp. 103-124 ◽  
Author(s):  
K. Takemura ◽  
M. Kahdre ◽  
D. Joseph ◽  
A. Yousef ◽  
S. Sreevatsan
Keyword(s):  
Prion Diseases ◽  
Infectious Agent ◽  
Transmissible Spongiform Encephalopathies ◽  
Causal Mechanism ◽  
Spongiform Encephalopathy ◽  
Spongiform Encephalopathies ◽  
Disease Diagnostics ◽  
New Variant ◽  
Jakob Disease ◽  
Underlying Mechanisms

AbstractTransmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders of humans and animals associated with an accumulation of abnormal isoforms of prion protein (PrP) in nerve cells. The pathogenesis of TSEs involves conformational conversions of normal cellular PrP (PrPc) to abnormal isoforms of PrP (PrPSc). While the protein-only hypothesis has been widely accepted as a causal mechanism of prion diseases, evidence from more recent research suggests a possible involvement of other cellular component(s) or as yet undefined infectious agent(s) in PrP pathogenesis. Although the underlying mechanisms of PrP strain variation and the determinants of interspecies transmissibility have not been fully elucidated, biochemical and molecular findings indicate that bovine spongiform encephalopathy in cattle and new-variant Creutzfeldt–Jakob disease in humans are caused by indistinguishable etiological agent(s). Cumulative evidence suggests that there may be risks of humans acquiring TSEs via a variety of exposures to infected material. The development of highly precise ligands is warranted to detect and differentiate strains, allelic variants and infectious isoforms of these PrPs. This article describes the general features of TSEs and PrP, the current understanding of their pathogenesis, recent advances in prion disease diagnostics, and PrP inactivation.

How to Limit the Spread of Creutzfeldt-Jakob Disease

1996 ◽  
Vol 17 (8) ◽  
pp. 521-528
Author(s):  
Dominique Dormont
Keyword(s):  
Blood Donation ◽  
Transmissible Spongiform Encephalopathy ◽  
Infected Individual ◽  
Experimental Models ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Spongiform Encephalopathies ◽  
Corneal Grafting ◽  
Jakob Disease ◽  
Spleen And Lymph Nodes

AbstractTransmissible spongiform encephalopathies are rare lethal diseases induced in humans and animals by unconventional agents called transmissible spongiform encephalopathy agents (TSEAs), virions, or prions. Several cases of iatrogenic Creutzfeldt-Jakob disease (CJD) have been reported in the literature after neuro-surgery, treatment with pituitary-derived hormones, corneal grafting, and use of dura mater lyophilisates. In a given infected individual, TSEA-associated infectiousness depends on the nature of the organ: the central nervous system has the highest infectiousness, spleen and lymph nodes a medium infectiousness, and organs such as bone, skin, or skeletal muscles do not harbor any detectable infectiousness in experimental models. Transmissible spongiform encephalopathy/prions have unconventional properties; in particular, they resist almost all the chemical and physical processes that inactivate conventional viruses. Therefore, prevention of CJD agent transmission must be taken into account in daily hospital practice. Efficient sterilization procedures should be determined. In tissue and blood donation, donors with a neurologic history must be excluded, and patients treated with pituitary-derived hormones should be considered potentially infected with TSEA and excluded.

scholarly journals Classical BSE prions emerge from asymptomatic pigs challenged with atypical/Nor98 scrapie

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Belén Marín ◽  
Alicia Otero ◽  
Séverine Lugan ◽  
Juan Carlos Espinosa ◽  
Alba Marín-Moreno ◽  
...  
Keyword(s):  
Protein Misfolding ◽  
Clinical Signs ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Post Inoculation ◽  
Atypical Scrapie ◽  
Wasting Disease ◽  
Spongiform Encephalopathies ◽  
Robust Transmission

AbstractPigs are susceptible to infection with the classical bovine spongiform encephalopathy (C-BSE) agent following experimental inoculation, and PrPSc accumulation was detected in porcine tissues after the inoculation of certain scrapie and chronic wasting disease isolates. However, a robust transmission barrier has been described in this species and, although they were exposed to C-BSE agent in many European countries, no cases of natural transmissible spongiform encephalopathies (TSE) infections have been reported in pigs. Transmission of atypical scrapie to bovinized mice resulted in the emergence of C-BSE prions. Here, we conducted a study to determine if pigs are susceptible to atypical scrapie. To this end, 12, 8–9-month-old minipigs were intracerebrally inoculated with two atypical scrapie sources. Animals were euthanized between 22- and 72-months post inoculation without clinical signs of TSE. All pigs tested negative for PrPSc accumulation by enzyme immunoassay, immunohistochemistry, western blotting and bioassay in porcine PrP mice. Surprisingly, in vitro protein misfolding cyclic amplification demonstrated the presence of C-BSE prions in different brain areas from seven pigs inoculated with both atypical scrapie isolates. Our results suggest that pigs exposed to atypical scrapie prions could become a reservoir for C-BSE and corroborate that C-BSE prions emerge during interspecies passage of atypical scrapie.

scholarly journals Scrapie susceptibility-associated indel polymorphism of shadow of prion protein gene (SPRN) in Korean native black goats

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yong-Chan Kim ◽  
Seon-Kwan Kim ◽  
Byung-Hoon Jeong
Keyword(s):  
Prion Protein ◽  
Protein Gene ◽  
Allele Frequencies ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Prion Protein Gene ◽  
Indel Polymorphism ◽  
Spongiform Encephalopathies ◽  
Direct Dna Sequencing ◽  
Significant Difference

Abstract Prion diseases in sheep and goats are called scrapie and belong to a group of transmissible spongiform encephalopathies (TSEs) caused by the abnormal misfolding of the prion protein encoded by the prion protein gene (PRNP). The shadow of the prion protein gene (SPRN) is the only prion gene family member that shows a protein expression profile similar to that of the PRNP gene in the central nervous system. In addition, genetic susceptibility of the SPRN gene has been reported in variant Creutzfeldt–Jakob disease (CJD), bovine spongiform encephalopathy (BSE) and scrapie. However, genetic studies of the SPRN gene have not been carried out in Korean native black goats. Here, we investigated the genotype and allele frequencies of SPRN polymorphisms in 213 Korean native black goats and compared these polymorphisms with those previously reported for scrapie-affected animals. We found a total of 6 polymorphisms including 1 nonsynonymous single nucleotide polymorphism (SNP) and 1 synonymous SNP in the open reading frame (ORF) region and 3 SNPs and 1 indel polymorphism (c.495_496insCTCCC) in the 3′ untranslated region (UTR) by direct DNA sequencing. A significant difference in the allele frequency of the c.495_496insCTCCC indel polymorphism was found between the Italian scrapie-affected goats and the Korean native black goats (P < 0.001). Furthermore, there was a significant difference in the allele frequencies of the c.495_496insCTCCC indel polymorphism between Italian healthy goats and Korean native black goats (P < 0.001). To evaluate the biological impact of the novel nonsynonymous SNP c.416G > A (Arg139Gln), we carried out PROVEAN analysis. PROVEAN predicted the SNP as ‘Neutral’ with a score of −0.297. To the best of our knowledge, this is the first genetic study of the SPRN gene in Korean native black goats.

Prions: Protein Aggregation and Infectious Diseases

2009 ◽  
Vol 89 (4) ◽  
pp. 1105-1152 ◽  
Author(s):  
Adriano Aguzzi ◽  
Anna Maria Calella
Keyword(s):  
Protein Aggregation ◽  
Prion Diseases ◽  
Physiological Role ◽  
Infectious Agent ◽  
Normal Function ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Pathological Features ◽  
Spongiform Encephalopathies

Transmissible spongiform encephalopathies (TSEs) are inevitably lethal neurodegenerative diseases that affect humans and a large variety of animals. The infectious agent responsible for TSEs is the prion, an abnormally folded and aggregated protein that propagates itself by imposing its conformation onto the cellular prion protein (PrPC) of the host. PrPCis necessary for prion replication and for prion-induced neurodegeneration, yet the proximal causes of neuronal injury and death are still poorly understood. Prion toxicity may arise from the interference with the normal function of PrPC, and therefore, understanding the physiological role of PrPCmay help to clarify the mechanism underlying prion diseases. Here we discuss the evolution of the prion concept and how prion-like mechanisms may apply to other protein aggregation diseases. We describe the clinical and the pathological features of the prion diseases in human and animals, the events occurring during neuroinvasion, and the possible scenarios underlying brain damage. Finally, we discuss potential antiprion therapies and current developments in the realm of prion diagnostics.

scholarly journals Prion Type-Dependent Deposition ofPRNPAllelic Products in Heterozygous Sheep

2015 ◽  
Vol 90 (2) ◽  
pp. 805-812 ◽  
Author(s):  
J. P. M. Langeveld ◽  
J. G. Jacobs ◽  
N. Hunter ◽  
L. J. M. van Keulen ◽  
F. Lantier ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Bovine Spongiform Encephalopathy ◽  
Prion Protein ◽  
Transmissible Spongiform Encephalopathy ◽  
Infected Sheep ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Sequence Variants ◽  
Spongiform Encephalopathies

ABSTRACTSusceptibility or resistance to prion infection in humans and animals depends on single prion protein (PrP) amino acid substitutions in the host, but the agent's modulating role has not been well investigated. Compared to disease incubation times in wild-type homozygous ARQ/ARQ (where each triplet represents the amino acids at codons 136, 154, and 171, respectively) sheep, scrapie susceptibility is reduced to near resistance in ARR/ARR animals while it is strongly enhanced in VRQ/VRQ carriers. Heterozygous ARR/VRQ animals exhibit delayed incubation periods. In bovine spongiform encephalopathy (BSE) infection, the polymorphism effect is quite different although the ARR allotype remains the least susceptible. In this study, PrP allotype composition in protease-resistant prion protein (PrPres) from brain of heterozygous ARR/VRQ scrapie-infected sheep was compared with that of BSE-infected sheep with a similar genotype. A triplex Western blotting technique was used to estimate the two allotype PrP fractions in PrPresmaterial from BSE-infected ARR/VRQ sheep. PrPresin BSE contained equimolar amounts of VRQ- and ARR-PrP, which contrasts with the excess (>95%) VRQ-PrP fraction found in PrP in scrapie. This is evidence that transmissible spongiform encephalopathy (TSE) agent properties alone, perhaps structural aspects of prions (such as PrP amino acid sequence variants and PrP conformational state), determine the polymorphic dependence of the PrPresaccumulation process in prion formation as well as the disease-associated phenotypic expressions in the host.IMPORTANCETransmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative and transmissible diseases caused by prions. Amino acid sequence variants of the prion protein (PrP) determine transmissibility in the hosts, as has been shown for classical scrapie in sheep. Each individual produces a separate PrP molecule from its two PrP gene copies. Heterozygous scrapie-infected sheep that produce two PrP variants associated with opposite scrapie susceptibilities (136V-PrP variant, high; 171R-PrP variant, very low) contain in their prion material over 95% of the 136V PrP variant. However, when these sheep are infected with prions from cattle (bovine spongiform encephalopathy [BSE]), both PrP variants occur in equal ratios. This shows that the infecting prion type determines the accumulating PrP variant ratio in the heterozygous host. While the host's PrP is considered a determining factor, these results emphasize that prion structure plays a role during host infection and that PrP variant involvement in prions of heterozygous carriers is a critical field for understanding prion formation.

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