Browsing by Person "Cancellotti, Enrico"

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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.
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.
How does host PrP control TSE disease?
(Springer, 2004-05) Manson, Jean; Barron, Rona; Tuzi, Nadia L.; Baybutt, Herbert; Bishop, Matthew; Cancellotti, Enrico; Hart, Patricia; Jamieson, L.; Aitchison, L.; Gall, E.; Bradford, Barry; King, Declan
PrP is central to the TSE disease process and has been hypothesised to be the infectious agent. Polymorphisms in the PrP gene of a number of species 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. In order 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. This strategy therefore allows the effect of specific mutations in the PrP gene to be assessed. We have introduced mutations into the Prnp gene which prevent glycosylation at each or both of the two N-linked glycosylation sites of PrP and are using TSE infection of these mice to investigate the role of PrP glycosylation in strain targeting and strain determination. We have investigated the role of the sequence of the host PrP gene in determining susceptibility by inserting point mutations or replacing the murine PrP gene with that of human or bovine PrP. This has produced a model of TSE disease which contains high levels of infectivity in the absence of PrPSc and we are using this model to determine the nature of the infectious agent. We have thus established that the gene targeting approach can produce models for TSE disease which address fundamental questions associated with these diseases. We aim to use these models to address central issues including the origin of strains, the species barrier and the nature of the infectious agent.
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.
The transmissible spongiform encephalopathies: emerging and declining epidemics
(Portland Press, 2006-10-25) Manson, Jean C.; Cancellotti, Enrico; Bishop, Matthew T.; Hart, Patricia; Barron, Rona
TSEs (transmissible spongiform encephalopathies) are neurodegenerative diseases of various mammalian species, the best known of which include BSE (bovine spongiform encephalopathies) in cattle, CJD (Creutzfeldt–Jakob disease) in humans, scrapie in sheep and CWD (chronic wasting disease) in deer. This review examines the emergence of various TSE strains and their transmission, and discusses disease surveillance and control.