Browsing by Person "Manson, Jean C."

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The 101L mutation in murine PrP can alter transmission across three species barriers
(2002) Barron, Rona; Jamieson, Elizabeth; Thomson, Val; Melton, David W.; Will, Robert; Ironside, James; Manson, Jean C.
Accumulation of prion protein in the brain that is not associated with transmissible disease
(National Academy of Sciences, 2007-03-13) Piccardo, Pedro; King, Declan; Ghetti, Bernardino; Manson, Jean C.; Barron, Rona
Prion diseases or transmissible spongiform encephalopathies are characterized histopathologically by the accumulation of prion protein (PrP) ranging from diffuse deposits to amyloid plaques. Moreover, pathologic PrP isoforms (PrPSc) are detected by immunoblot analysis and used both as diagnostic markers of disease and as indicators of the presence of infectivity in tissues. It is not known which forms of PrP are associated with infectivity. To address this question, we performed bioassays using human brain extracts from two cases with phenotypically distinct forms of familial prion disease (Gerstmann-Sträussler-Scheinker P102L). Both cases had PrP accumulations in the brain, but each had different PrPSc isoforms. Only one of the brains had spongiform degeneration. Tissue from this case transmitted disease efficiently to transgenic mice (Tg PrP101LL), resulting in spongiform encephalopathy. In contrast, inoculation of tissue from the case with no spongiform degeneration resulted in almost complete absence of disease transmission but elicited striking PrP-amyloid deposition in several recipient mouse brains. Brains of these mice failed to transmit any neurological disease on passage, but PrP-amyloid deposition was again observed in the brains of recipient mice. These data suggest the possible isolation of an infectious agent that promotes PrP amyloidogenesis in the absence of a spongiform encephalopathy. Alternatively, the infectious agent may be rendered nonpathogenic by sequestration in amyloid plaques, or PrP amyloid can seed amyloid accumulation in the brain, causing a proteinopathy that is unrelated to prion disease. Formation of PrP amyloid may therefore not necessarily be a reliable marker of transmissible spongiform encephalopathy infectivity.
Changing a single amino acid in the N-terminus of murine PrP alters incubation time across three species barriers
(EMBO Press, 2001-09-17) Barron, Rona; Thomson, Val; Jamieson, Elizabeth; Melton, David W.; Ironside, James; Will, Robert; Manson, Jean C.
The PrP gene of the host exerts a major influence over the outcome of transmissible spongiform encephalopathy (TSE) disease, but the mechanism by which this is achieved is not understood. We have introduced a specific mutation into the endogenous murine PrP gene using gene targeting to produce transgenic mice with a single amino acid alteration (proline to leucine) at amino acid position 101 in their PrP protein (P101L). The effect of this alteration on incubation time, targeting and PrPSc formation has been studied in TSE-infected animals. Transgenic mice carrying the P101L mutation in PrP have remarkable differences in incubation time and targeting of central nervous system pathology compared with wild-type littermates, following inoculation with infectivity from human, hamster, sheep and murine sources. This single mutation can alter incubation time across three species barriers in a strain-dependent manner. These findings suggest a critical role for the structurally ‘flexible’ region of PrP in agent replication and targeting of TSE pathology.
Chronic wasting disease and atypical forms of bovine spongiform encephalopathy and scrapie are not transmissible to mice expressing wild-type levels of human prion protein
(Microbiology Society, 2012-07-01) Wilson, Rona; Plinston, Chris; Hunter, Nora; Casalone, Cristina; Corona, Cristiano; Tagliavini, Fabrizio; Suardi, SIlvia; Ruggerone, Margherita; Graziano, Silvia; Sbriccoli, Marco; Cardone, Franco; Pocchiari, Maurizio; Ingrosso, Loredana; Baron, Thierry; Richt, Juergen; Andreoletti, Olivier; Simmons, Marion; Lockey, Richard; Manson, Jean C.; Barron, Rona
The association between bovine spongiform encephalopathy (BSE) and variant Creutzfeldt–Jakob disease (vCJD) has demonstrated that cattle transmissible spongiform encephalopathies (TSEs) can pose a risk to human health and raises the possibility that other ruminant TSEs may be transmissible to humans. In recent years, several novel TSEs in sheep, cattle and deer have been described and the risk posed to humans by these agents is currently unknown. In this study, we inoculated two forms of atypical BSE (BASE and H-type BSE), a chronic wasting disease (CWD) isolate and seven isolates of atypical scrapie into gene-targeted transgenic (Tg) mice expressing the human prion protein (PrP). Upon challenge with these ruminant TSEs, gene-targeted Tg mice expressing human PrP did not show any signs of disease pathology. These data strongly suggest the presence of a substantial transmission barrier between these recently identified ruminant TSEs and humans.
Dissociation of Prion Protein Amyloid Seeding from Transmission of a Spongiform Encephalopathy
(American Society for Microbiology, 2013-11-15) Piccardo, Pedro; King, Declan; Telling, Glenn; Manson, Jean C.; Barron, Rona
Misfolding and aggregation of proteins are common pathogenic mechanisms of a group of diseases called proteinopathies. The formation and spread of proteinaceous lesions within and between individuals were first described in prion diseases and proposed as the basis of their infectious nature. Recently, a similar “prion-like” mechanism of transmission has been proposed in other neurodegenerative diseases such as Alzheimer's disease. We investigated if misfolding and aggregation of corrupted prion protein (PrPTSE) are always associated with horizontal transmission of disease. Knock-in transgenic mice (101LL) expressing mutant PrP (PrP-101L) that are susceptible to disease but do not develop any spontaneous neurological phenotype were inoculated with (i) brain extracts containing PrPTSE from healthy 101LL mice with PrP plaques in the corpus callosum or (ii) brain extracts from mice overexpressing PrP-101L with neurological disease, severe spongiform encephalopathy, and formation of proteinase K-resistant PrPTSE. In all instances, 101LL mice developed PrP plaques in the area of inoculation and vicinity in the absence of clinical disease or spongiform degeneration of the brain. Importantly, 101LL mice did not transmit disease on serial passage, ruling out the presence of subclinical infection. Thus, in both experimental models the formation of PrPTSE is not infectious. These results have implications for the interpretation of tests based on the detection of protein aggregates and suggest that de novo formation of PrPTSE in the host does not always result in a transmissible prion disease. In addition, these results question the validity of assuming that all diseases due to protein misfolding can be transmitted between individuals.
Gene Targeting the PrP Gene
(Horizon Bioscience, 2004) Barron, Rona; Manson, Jean C.
A gene-targeted mouse model of P102L Gerstmann-Sträussler-Scheinker syndrome
(Elsevier, 2003-03) Barron, Rona; Manson, Jean C.
Glycosylation of PrPC Determines Timing of Neuroinvasion and Targeting in the Brain following Transmissible Spongiform Encephalopathy Infection by a Peripheral Route
(American Society for Microbiology, 2010-04-01) Cancellotti, Enrico; Bradford, Barry M.; Tuzi, Nadia L.; Hickey, Raymond D.; Brown, Debbie; Brown, Karen L.; Barron, Rona; Kisielewski, Dorothy; Piccardo, Pedro; Manson, Jean C.
Transmissible spongiform encephalopathy (TSE) infectivity naturally spreads from site of entry in the periphery to the central nervous system where pathological lesions are formed. Several routes and cells within the host have been identified as important for facilitating the infectious process. Expression of the glycoprotein cellular PrP (PrPC) is considered a key factor for replication of infectivity in the central nervous system (CNS) and its transport to the brain, and it has been suggested that the infectious agent propagates from cell to cell via a domino-like effect. However, precisely how this is achieved and what involvement the different glycoforms of PrP have in these processes remain to be determined. To address this issue, we have used our unique models of gene-targeted transgenic mice expressing different glycosylated forms of PrP. Two TSE strains were inoculated intraperitoneally into these mice to assess the contribution of diglycosylated, monoglycosylated, and unglycosylated PrP in spreading of infectivity to the brain. This study demonstrates that glycosylation of host PrP has a profound effect in determining the outcome of disease. Lack of diglycosylated PrP slowed or prevented disease onset after peripheral challenge, suggesting an important role for fully glycosylated PrP in either the replication of the infectious agent in the periphery or its transport to the CNS. Moreover, mice expressing unglycosylated PrP did not develop clinical disease, and mice expressing monoglycosylated PrP showed strikingly different neuropathologic features compared to those expressing diglycosylated PrP. This demonstrates that targeting in the brain following peripheral inoculation is profoundly influenced by the glycosylation status of host PrP.
High Titers of Transmissible Spongiform Encephalopathy Infectivity Associated with Extremely Low Levels of PrPSc in Vivo
(American Society for Biochemistry and Molecular Biology, 2007-10-08) Barron, Rona; Campbell, Susan L.; King, Declan; Bellon, Anne; Chapman, Karen E.; Williamson, R. Anthony; Manson, Jean C.
Diagnosis of transmissible spongiform encephalopathy (TSE) disease in humans and ruminants relies on the detection in post-mortem brain tissue of the protease-resistant form of the host glycoprotein PrP. The presence of this abnormal isoform (PrPSc) in tissues is taken as indicative of the presence of TSE infectivity. Here we demonstrate conclusively that high titers of TSE infectivity can be present in brain tissue of animals that show clinical and vacuolar signs of TSE disease but contain low or undetectable levels of PrPSc. This work questions the correlation between PrPSc level and the titer of infectivity and shows that tissues containing little or no proteinase K-resistant PrP can be infectious and harbor high titers of TSE infectivity. Reliance on protease-resistant PrPSc as a sole measure of infectivity may therefore in some instances significantly underestimate biological properties of diagnostic samples, thereby undermining efforts to contain and eradicate TSEs.
Host PrP Glycosylation: A Major Factor Determining the Outcome of Prion Infection
(Public Library of Science, 2008-04-15) Tuzi, Nadia L.; Cancellotti, Enrico; Baybutt, Herbert; Blackford, Lorraine; Bradford, Barry; Pinston, Chris; Coghill, Anne; Hart, Patricia; Piccardo, Pedro; Barron, Rona; Manson, Jean C.
The expression of the prion protein (PrP) is essential for transmissible spongiform encephalopathy (TSE) or prion diseases to occur, but the underlying mechanism of infection remains unresolved. To address the hypothesis that glycosylation of host PrP is a major factor influencing TSE infection, we have inoculated gene-targeted transgenic mice that have restricted N-linked glycosylation of PrP with three TSE strains. We have uniquely demonstrated that mice expressing only unglycosylated PrP can sustain a TSE infection, despite altered cellular location of the host PrP. Moreover we have shown that brain material from mice infected with TSE that have only unglycosylated PrPSc is capable of transmitting infection to wild-type mice, demonstrating that glycosylation of PrP is not essential for establishing infection within a host or for transmitting TSE infectivity to a new host. We have further dissected the requirement of each glycosylation site and have shown that different TSE strains have dramatically different requirements for each of the glycosylation sites of host PrP, and moreover, we have shown that the host PrP has a major role in determining the glycosylation state of de novo generated PrPSc.
Increased Susceptibility of Human-PrP Transgenic Mice to Bovine Spongiform Encephalopathy Infection following Passage in Sheep
(American Society for Microbiology, 2011-01-12) Plinston, Chris; Hart, Patricia; Chong, Angela; Piccardo, Pedro; Hunter, Nora; Foster, James; Manson, Jean C.; Barron, Rona
The risk of the transmission of ruminant transmissible spongiform encephalopathy (TSE) to humans was thought to be low due to the lack of association between sheep scrapie and the incidence of human TSE. However, a single TSE agent strain has been shown to cause both bovine spongiform encephalopathy (BSE) and human vCJD, indicating that some ruminant TSEs are transmissible to humans. While the transmission of cattle BSE to humans in transgenic mouse models has been inefficient, indicating the presence of a significant transmission barrier between cattle and humans, BSE has been transmitted to a number of other species. Here, we aimed to further investigate the human transmission barrier following the passage of BSE in a sheep. Following inoculation with cattle BSE, gene-targeted transgenic mice expressing human PrP showed no clinical or pathological signs of TSE disease. However, following inoculation with an isolate of BSE that had been passaged through a sheep, TSE-associated vacuolation and proteinase K-resistant PrP deposition were observed in mice homozygous for the codon 129-methionine PRNP gene. This observation may be due to higher titers of the BSE agent in sheep or an increased susceptibility of humans to BSE prions following passage through a sheep. However, these data confirm that, contrary to previous predictions, it is possible that a sheep prion is transmissible to humans and that BSE from other species is a public health risk.
Increased susceptibility of transgenic mice expressing human PrP to experimental sheep bovine spongiform encephalopathy is not due to increased agent titre in sheep brain tissue
(Microbiology Society, 2014-08-01) Plinston, Chris; Hart, Patricia; Hunter, Nora; Manson, Jean C.; Barron, Rona
Bovine spongiform encephalopathy (BSE) in cattle and variant Creutzfeldt–Jakob disease in humans have previously been shown to be caused by the same strain of transmissible spongiform encephalopathy agent. It is hypothesized that the agent spread to humans following consumption of food products prepared from infected cattle. Despite evidence supporting zoonotic transmission, mouse models expressing human prion protein (HuTg) have consistently shown poor transmission rates when inoculated with cattle BSE. Higher rates of transmission have however been observed when these mice are exposed to BSE that has been experimentally transmitted through sheep or goats, indicating that humans may potentially be more susceptible to BSE from small ruminants. Here we demonstrate that increased transmissibility of small ruminant BSE to HuTg mice was not due to replication of higher levels of infectivity in sheep brain tissue, and is instead due to other specific changes in the infectious agent.
Insights into Mechanisms of Chronic Neurodegeneration
(MDPI, 2016-01-12) Diack, Abigail B.; Alibhai, James D.; Barron, Rona; Bradford, Barry; Piccardo, Pedro; Manson, Jean C.
Chronic neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and prion diseases are characterised by the accumulation of abnormal conformers of a host encoded protein in the central nervous system. The process leading to neurodegeneration is still poorly defined and thus development of early intervention strategies is challenging. Unique amongst these diseases are Transmissible Spongiform Encephalopathies (TSEs) or prion diseases, which have the ability to transmit between individuals. The infectious nature of these diseases has permitted in vivo and in vitro modelling of the time course of the disease process in a highly reproducible manner, thus early events can be defined. Recent evidence has demonstrated that the cell-to-cell spread of protein aggregates by a “prion-like mechanism” is common among the protein misfolding diseases. Thus, the TSE models may provide insights into disease mechanisms and testable hypotheses for disease intervention, applicable to a number of these chronic neurodegenerative diseases.
Knockouts, Knockins, Transgenics and Transplants in Prion Research
(Cold Spring Harbor Laboratory Press, 2004) Weissman, C; Fleschig, E; Barron, Rona; Aguzzi, A; Manson, Jean C.
Mechanism of PrP-Amyloid Formation in Mice Without Transmissible Spongiform Encephalopathy
(Wiley, 2011-06-03) Jeffrey, Martin; McGovern, Gillian; Chambers, Emily V.; King, Declan; Gonzalez, Lorenzo; Manson, Jean C.; Ghetti, Bernardino; Piccardo, Pedro; Barron, Rona
Gerstmann–Sträussler–Scheinker (GSS) P102L disease is a familial form of a transmissible spongiform encephalopathy (TSE) that can present with or without vacuolation of neuropil. Inefficient disease transmission into 101LL transgenic mice was previously observed from GSS P102L without vacuolation. However, several aged, healthy mice had large plaques composed of abnormal prion protein (PrPd). Here we perform the ultrastructural characterization of such plaques and compare them with PrPd aggregates found in TSE caused by an infectious mechanism. PrPd plaques in 101LL mice varied in maturity, with some being composed of deposits without visible amyloid fibrils. PrPd was present on cell membranes in the vicinity of all types of plaques. In contrast to the unicentric plaques seen in infectious murine scrapie, the plaques seen in the current model were multicentric and were initiated by protofibrillar forms of PrPd situated on oligodendroglia, astrocytes and neuritic cell membranes. We speculate that the initial conversion process leading to plaque formation begins with membrane-bound PrPC but that subsequent fibrillization does not require membrane attachment. We also observed that the membrane alterations consistently seen in murine scrapie and other infectious TSEs were not present in 101LL mice with plaques, suggesting differences in the pathogenesis of these conditions.
Polymorphisms at codons 108 and 189 in murine PrP play distinct roles in the control of scrapie incubation time
(Microbiology Society, 2005-03-01) Barron, Rona; Baybutt, Herbert; Tuzi, Nadia L.; McCormack, James; King, Declan; Moore, Richard C.; Melton, David W.; Manson, Jean C.
Susceptibility to transmissible spongiform encephalopathies (TSEs) is associated strongly with PrP polymorphisms in humans, sheep and rodents. In mice, scrapie incubation time is controlled by polymorphisms at PrP codons 108 (leucine or phenylalanine) and 189 (threonine or valine), but the precise role of each polymorphism in the control of disease is unknown. The L108F and T189V polymorphisms are present in distinct structural regions of PrP and thus provide an excellent model with which to investigate the role of PrP structure and gene variation in TSEs. Two unique lines of transgenic mice, in which 108F and 189V have been targeted separately into the endogenous murine Prnp a gene, have been produced. TSE inoculation of inbred lines of mice expressing all allelic combinations at codons 108 and 189 has revealed a complex relationship between PrP allele and incubation time. It has been established that both codons 108 and 189 control TSE incubation time, and that each polymorphism plays a distinct role in the disease process. Comparison of ME7 incubation times in mouse lines that are heterozygous at both codons has also identified a previously unrecognized intramolecular interaction between PrP codons 108 and 189.
The role of host PrP in control of incubation time
(Springer Verlag, 2005) Manson, Jean C.; Barron, Rona; Hart, Patricia; Tuzi, Nadia L.; Bishop, Matthew T.
PrP is central to TSE disease and has been hypothesised to be the infectious agent. Polymorphisms in the PrP gene are associated with different incubation times of disease following exposure to an infectious agent and mutations in the human PrP gene can apparently lead to spontaneous genetic disease. Strains of TSE agent are proposed to be generated and maintained through differences in glycosylation or conformation of PrP and the barrier to infection between species is thought to be due to the differences in the sequence of PrP between different species. To test these hypotheses, we have introduced specific modifications into the endogenous mouse Prnp gene by gene targeting. The mutated PrP gene is in the correct location under the control of the endogenous Prnp regulatory sequences and thus expressed in the same tissues and amounts as the wild type Prnp gene. By altering the murine PrP coding region to that of another species we have established that increasing overall identity between host and donor PrP can lead to either an increase or a decrease in incubation time of disease in a strain dependent manner. We have introduced a point mutation (101L) into the N-terminus of the host PrP and shown that it dramatically changes the susceptibility of the host to infection from different species. We have in addition demonstrated that polymorphisms in the N terminus (L108T) and C-terminus (F189V) of host PrP both alter the incubation time of disease. We have in addition introduced mutations into the Prnp gene which prevent glycosylation at each or both of the two N-linked glycosylation sites of PrP. Inoculation of these mice with infectivity has established that glycosylation of host PrP can influence incubation time of disease, vacuolar pathology and strain determination.
The role of host PrP in Transmissible Spongiform Encephalopathy
(Elsevier, 2007-06) Cancellotti, Enrico; Barron, Rona; Bishop, Matthew T.; Hart, Patricia; Wiseman, Patricia; Manson, Jean C.
PrP has a central role in the Transmissible Spongiform Encephalopathies (TSEs), and mutations and polymorphisms in host PrP can profoundly alter the host's susceptibility to a TSE agent. However, precisely how host PrP influences the outcome of disease has not been established. To investigate this we have produced by gene targeting a series of inbred lines of transgenic mice expressing different PrP genes. This allows us to study directly the influence of the host PrP gene in TSEs. We have examined the role of glycosylation, point mutations, polymorphisms and PrP from different species on host susceptibility and the disease process both within the murine species and across species barriers.
A single amino acid alteration (101L) introduced into murine PrP dramatically alters incubation time of transmissible spongiform encephalopathy
(EMBO Press, 1999-12-01) Manson, Jean C.; Jamieson, Elizabeth; Baybutt, Herbert; Tuzi, Nadia L.; Barron, Rona; McConnell, Irene; Somerville, Robert; Ironside, James; Will, Robert; Sy, Man-Sun; Melton, David W.; Hope, James; Bostock, Christopher
A mutation equivalent to P102L in the human PrP gene, associated with Gerstmann–Straussler syndrome (GSS), has been introduced into the murine PrP gene by gene targeting. Mice homozygous for this mutation (101LL) showed no spontaneous transmissible spongiform encephalopathy (TSE) disease, but had incubation times dramatically different from wild-type mice following inoculation with different TSE sources. Inoculation with GSS produced disease in 101LL mice in 288 days. Disease was transmitted from these mice to both wild-type (226 days) and 101LL mice (148 days). In contrast, 101LL mice infected with ME7 had prolonged incubation times (338 days) compared with wild-type mice (161 days). The 101L mutation does not, therefore, produce any spontaneous genetic disease in mice but significantly alters the incubation time of TSE infection. Additionally, a rapid TSE transmission was demonstrated despite extremely low levels of disease-associated PrP.
The transmissible spongiform encephalopathies.
(Cambridge University Press, 2005-04) Manson, Jean C.; Barron, Rona; Diggard, P.; Nash, A.A.; Randall, R.E.