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Abstract
Since its discovery the cellular prion protein (encoded by the Prnp gene) has been associated with a large number of functions. The proposed functions rank from basic cellular processes such as cell cycle and survival to neural functions such as behavior and neuroprotection, following a pattern similar to that of Moore's law for electronics. In addition, particular interest is increasing in the participation of Prnp in neurodegeneration. However, in recent years a redefinition of these functions has begun, since examples of previously attributed functions were increasingly re-associated with other proteins. Most of these functions are linked to so-called "Prnp-flanking genes" that are close to the genomic locus of Prnp and which are present in the genome of some Prnp mouse models. In addition, their role in neuroprotection against convulsive insults has been confirmed in recent studies. Lastly, in recent years a large number of models indicating the participation of different domains of the protein in apoptosis have been uncovered. However, after more than 10 years of molecular dissection our view is that the simplest mechanistic model in PrP(C)-mediated cell death should be considered, as Ockham's razor theory suggested.
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Affiliation(s)
- José A del Río
- a Molecular and Cellular Neurobiotechnology, Institute for Bioengineering of Catalonia (IBEC) , Parc Científic de Barcelona, Barcelona , Spain.,b Department of Cell Biology, Physiology and Inmunology , Facultat de Biologia, Universitat de Barcelona , Barcelona , Spain.,c Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Barcelona , Spain
| | - Rosalina Gavín
- a Molecular and Cellular Neurobiotechnology, Institute for Bioengineering of Catalonia (IBEC) , Parc Científic de Barcelona, Barcelona , Spain.,b Department of Cell Biology, Physiology and Inmunology , Facultat de Biologia, Universitat de Barcelona , Barcelona , Spain.,c Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Barcelona , Spain
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Sakudo A, Onodera T. Prion protein (PrP) gene-knockout cell lines: insight into functions of the PrP. Front Cell Dev Biol 2015; 2:75. [PMID: 25642423 PMCID: PMC4295555 DOI: 10.3389/fcell.2014.00075] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/22/2014] [Indexed: 11/13/2022] Open
Abstract
Elucidation of prion protein (PrP) functions is crucial to fully understand prion diseases. A major approach to studying PrP functions is the use of PrP gene-knockout (Prnp (-/-)) mice. So far, six types of Prnp (-/-) mice have been generated, demonstrating the promiscuous functions of PrP. Recently, other PrP family members, such as Doppel and Shadoo, have been found. However, information obtained from comparative studies of structural and functional analyses of these PrP family proteins do not fully reveal PrP functions. Recently, varieties of Prnp (-/-) cell lines established from Prnp (-/-) mice have contributed to the analysis of PrP functions. In this mini-review, we focus on Prnp (-/-) cell lines and summarize currently available Prnp (-/-) cell lines and their characterizations. In addition, we introduce the recent advances in the methodology of cell line generation with knockout or knockdown of the PrP gene. We also discuss how these cell lines have provided valuable insights into PrP functions and show future perspectives.
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Affiliation(s)
- Akikazu Sakudo
- Laboratory of Biometabolic Chemistry, Faculty of Medicine, School of Health Sciences, University of the Ryukyus Nishihara, Japan
| | - Takashi Onodera
- Research Center for Food Safety, School of Agricultural and Life Sciences, University of Tokyo Tokyo, Japan
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Onodera T, Sakudo A, Wu G, Saeki K. Bovine Spongiform Encephalopathy in Japan: History and Recent Studies on Oxidative Stress in Prion Diseases. Microbiol Immunol 2013; 50:565-78. [PMID: 16924141 DOI: 10.1111/j.1348-0421.2006.tb03831.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
With the respect to BSE and vCJD, compliance with the following three rules should strictly be observed: (i) Identification and destruction of all clinically affected cattle; (ii) destruction of all mammalian proteins used in feeding ruminant livestock; and (iii) destruction of all high-risk tissues for use in human consumption. Scrapie in sheep has been documented in the 18th century in the United Kingdom. Through studies of brain-to-brain transmission in the same species in 1935, Cuille et al. successfully isolated the culprit protein from the sheep brain. To transmit said protein from an animal to another, intracerebral inoculation was much more efficient than intraperitoneal or oral route in certain species; i.e. the hamster and mouse. Since discovery of the more efficacious infection route, studies and development of prion research have undergone 4 developmental phases. Phase I depicted discoveries of the pathological features of Creutzfeldt-Jakob disease (CJD) and scrapie with typical lesions of spongiform encephalopathy, while Phase II revealed individual-to-individual (or cross-species) transmissions of CJD, kuru and scrapie in animals. Phases I and II suggested the possible participation of a slow virus in the infection process. In Phase III, Prusiner et al. proposed the 'prion' theory in 1982, followed by the milestone development of the transgenic or gene-targeted mouse in prion research in Phase IV. By strain-typing of prions, CJD has been classified as type 2 or 4 by Parchi et al. and Wadsworth as type-2 or -4 and type-1 or -2, respectively. Wadsworth type 1 is detected in the cerebellum, while Wadsworth type 2 was detected in the prefrontal cortex of 10% of sporadic CJD patients. In 1999, Puoti et al. have reported the co-existence of two types of PrP(res) in a same patient. These reports indicated that PrP(res)-typing is a quantitative rather than a qualitative process, and the relationship between the molecular type and the prion strain is rather complex. In fact, previous findings of Truchot have correlated type-1 distribution with synaptic deposits, and type-2 with arrangement of diffuse deposits in neurons. Although the normal function of PrP(C) has not been fully understood, recent studies have shown that PrP(C) plays a role in copper metabolism, signal transduction, neuroprotection and cell maturation. Further search of PrP(C)-interacting molecules and detailed studies using Prnp(-/-) mice and various type of Prnp(-/-) cell lines under various conditions are the prerequisites in elucidating PrP functions. In the pathogenesis of prion diseases, present results support the hypothesis that 'loss-of-function' of PrP(C) decreases resistance to oxidative stress, and 'gain-of-function' of PrP(Sc) increases oxidative stress. The mechanisms of (i) the 'loss-of-function' of PrP(C) in enhanced susceptibility to oxidative stress and (ii) the 'gain-of-function' of PrP(Sc) in generation of oxidative stress remain to be elucidated, although their mechanisms of action, at least in part, involve the decrease and increase in SOD activity, respectively.
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Affiliation(s)
- Takashi Onodera
- Department of Molecular Immunology, School of Agricultural and Life Sciences, University of Tokyo
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Didonna A, Sussman J, Benetti F, Legname G. The role of Bax and caspase-3 in doppel-induced apoptosis of cerebellar granule cells. Prion 2012; 6:309-16. [PMID: 22561161 PMCID: PMC3399532 DOI: 10.4161/pri.20026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Doppel (Dpl) protein is a paralog of the prion protein (PrP) that shares 25% sequence similarity with the C-terminus of PrP, a common N-glycosylation site and a C-terminal signal peptide for attachment of a glycosylphophatidyl inositol anchor. Whereas PrPC is highly expressed in the central nervous system (CNS), Dpl is detected mostly in testes and its ectopic expression in the CNS leads to ataxia as well as Purkinje and granule cell degeneration in the cerebellum. The mechanism through which Dpl induces neurotoxicity is still debated. In the present work, primary neuronal cultures derived from postnatal cerebellar granule cells of wild-type and PrP-knockout FVB mice were used in order to investigate the molecular events that occur upon exposure to Dpl. Treatment of cultured cerebellar neurons with recombinant Dpl produced apoptosis that could be prevented by PrP co-incubation. When primary neuronal cultures from Bax-deficient mice were incubated with Dpl, no apoptosis was observed, suggesting an important role of Bax in triggering neurodegeneration. Similarly, cell survival increased when recDpl-treated cells were incubated with an inhibitor of caspase-3, which mediates apoptosis in mammalian cells. Together, our findings raise the possibility that Bax and caspase-3 feature in Dpl-mediated apoptosis.
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Affiliation(s)
- Alessandro Didonna
- Neurobiology Sector, Laboratory of Prion Biology, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
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Westaway D, Daude N, Wohlgemuth S, Harrison P. The PrP-Like Proteins Shadoo and Doppel. Top Curr Chem (Cham) 2011; 305:225-56. [DOI: 10.1007/128_2011_190] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
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Guillot-Sestier MV, Sunyach C, Druon C, Scarzello S, Checler F. The alpha-secretase-derived N-terminal product of cellular prion, N1, displays neuroprotective function in vitro and in vivo. J Biol Chem 2010; 284:35973-86. [PMID: 19850936 DOI: 10.1074/jbc.m109.051086] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cellular prion protein (PrP(c)) undergoes a disintegrin-mediated physiological cleavage, generating a soluble amino-terminal fragment (N1), the function of which remained unknown. Recombinant N1 inhibits staurosporine-induced caspase-3 activation by modulating p53 transcription and activity, whereas the PrP(c)-derived pathological fragment (N2) remains biologically inert. Furthermore, N1 protects retinal ganglion cells from hypoxia-induced apoptosis, reduces the number of terminal deoxynucleotidyltransferase-mediated biotinylated UTP nick end labeling-positive and p53-immunoreactive neurons in a pressure-induced ischemia model of the rat retina and triggers a partial recovery of b-waves but not a-waves of rat electroretinograms. Our work is the first demonstration that the alpha-secretase-derived PrP(c) fragment N1, but not N2, displays in vivo and in vitro neuroprotective function by modulating p53 pathway. It further demonstrates that distinct N-terminal cleavage products of PrP(c) harbor different biological activities underlying the various phenotypes linking PrP(c) to cell survival.
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Affiliation(s)
- Marie-Victoire Guillot-Sestier
- Institut de Pharmacologie Moléculaire et Cellulaire and Institut de Neuromédecine Moléculaire, UMR6097 CNRS/UNSA, Equipe Labellisée Fondation pour la Recherche Médicale, 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France
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Gilch S, Krammer C, Schätzl HM. Targeting prion proteins in neurodegenerative disease. Expert Opin Biol Ther 2008; 8:923-40. [PMID: 18549323 DOI: 10.1517/14712598.8.7.923] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Spongiform neurodegeneration is the pathological hallmark of individuals suffering from prion disease. These disorders, whose manifestation is sporadic, familial or acquired by infection, are caused by accumulation of the aberrantly folded isoform of the cellular prion protein (PrP(c)), termed PrP(Sc). Although usually rare, prion disorders are inevitably fatal and transferrable by infection. OBJECTIVE Pathology is restricted to the central nervous system and premortem diagnosis is usually not possible. Yet, promising approaches towards developing therapeutic regimens have been made recently. METHODS The biology of prion proteins and current models of neurotoxicity are discussed and prophylactic and therapeutic concepts are introduced. RESULTS/CONCLUSIONS Although various promising drug candidates with antiprion activity have been identified, this proof-of-concept cannot be transferred into translational medicine yet.
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Affiliation(s)
- Sabine Gilch
- Technische Universität München, Institute of Virology, Prion Research Group, Trogerstreet 30, 81675 Munich, Germany
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Christensen HM, Harris DA. Prion protein lacks robust cytoprotective activity in cultured cells. Mol Neurodegener 2008; 3:11. [PMID: 18718018 PMCID: PMC2546390 DOI: 10.1186/1750-1326-3-11] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Accepted: 08/21/2008] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The physiological function of the cellular prion protein (PrPC) remains unknown. However, PrPC has been reported to possess a cytoprotective activity that prevents death of neurons and other cells after a toxic stimulus. To explore this effect further, we attempted to reproduce several of the assays in which a protective activity of PrP had been previously demonstrated in mammalian cells. RESULTS In the first set of experiments, we found that PrP over-expression had a minimal effect on the death of MCF-7 breast carcinoma cells treated with TNF-alpha and Prn-p0/0 immortalized hippocampal neurons (HpL3-4 cells) subjected to serum deprivation. In the second set of assays, we observed only a small difference in viability between cerebellar granule neurons cultured from PrP-null and control mice in response to activation of endogenous or exogenous Bax. CONCLUSION Taken together, our results suggest either that cytoprotection is not a physiologically relevant activity of PrPC, or that PrPC-dependent protective pathways operative in vivo are not adequately modeled by these cell culture systems. We suggest that cell systems capable of mimicking the neurotoxic effects produced in transgenic mice by N-terminally deleted forms of PrP or Doppel may represent more useful tools for analyzing the cytoprotective function of PrPC.
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Affiliation(s)
- Heather M Christensen
- Department of Cell Biology and Physiology, Washington University School of Medicine, 660 South Euclid Avenue, St, Louis, MO 63110, USA.
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Heitz S, Gautheron V, Lutz Y, Rodeau JL, Zanjani HS, Sugihara I, Bombarde G, Richard F, Fuchs JP, Vogel MW, Mariani J, Bailly Y. BCL-2 counteracts Doppel-induced apoptosis of prion-protein-deficient Purkinje cells in the Ngsk Prnp(0/0) mouse. Dev Neurobiol 2008; 68:332-48. [PMID: 18085563 DOI: 10.1002/dneu.20555] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The pro-apoptotic factor BAX has recently been shown to contribute to Purkinje cell (PC) apoptosis induced by the neurotoxic prion-like protein Doppel (Dpl) in the prion-protein-deficient Ngsk Prnp(0/0) (NP(0/0)) mouse. In view of cellular prion protein (PrP(c)) ability to counteract Dpl neurotoxicity and favor neuronal survival like BCL-2, we investigated the effects of the anti-apoptotic factor BCL-2 on Dpl neurotoxicity by studying the progression of PC death in aging NP(0/0)-Hu-bcl-2 double mutant mice overexpressing human BCL-2 (Hu-bcl-2). Quantitative analysis showed that significantly more PCs survived in NP(0/0)-Hu-bcl-2 double mutants compared with the NP(0/0) mutants. However, number of PCs remained inferior to wild-type levels and to the increased number of PCs observed in Hu-bcl-2 mutants. In the NP(0/0) mutants, Dpl-induced PC death occurred preferentially in the aldolase C-negative parasagittal compartments of the cerebellar cortex. Activation of glial cells exclusively in these compartments, which was abolished by the expression of Hu-bcl-2 in the double mutants, suggested that chronic inflammation is an indirect consequence of Dpl-induced PC death. This partial rescue of NP(0/0) PCs by Hu-bcl-2 expression was similar to that observed in NP(0/0):Bax(-/-) double mutants with bax deletion. Taken together, these data strongly support the involvement of BCL-2 family-dependent apoptotic pathways in Dpl neurotoxicity. The capacity of BCL-2 to compensate PrP(c) deficiency by rescuing PCs from Dpl-induced death suggests that the BCL-2-like property of PrP(c) may impair Dpl-like neurotoxic pathways in wild-type neurons.
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Affiliation(s)
- S Heitz
- Département Neurotransmission et Sécrétion Neuroendocrine, UMR7168-LC2 CNRS, France.
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Wiggins RC. Prion stability and infectivity in the environment. Neurochem Res 2008; 34:158-68. [PMID: 18483857 DOI: 10.1007/s11064-008-9741-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Accepted: 05/02/2008] [Indexed: 02/07/2023]
Abstract
The biology of normal prion protein and the property of infectivity observed in abnormal folding conformations remain thinly characterized. However, enough is known to understand that prion proteins stretch traditional views of proteins in biological systems. Numerous investigators are resolving details of the novel mechanism of infectivity, which appears to feature a protein-only, homologous replication of misfolded isoforms. Many other features of prion biology are equally extraordinary. This review focuses on the status of infectious prions in various natural and man-made environments. The picture that emerges is that prion proteins are durable under extreme conditions of environmental exposure that are uncommon in biological phenomena, and this durability offers the potential for environmental reservoirs of persistent infectivity lasting for years. A recurrent theme in prion research is a propensity for these proteins to bind to mineral and metal surfaces, and several investigators have provided evidence that the normal cellular functions of prion protein may include metalloprotein interactions. This structural propensity for binding to mineral and metal ions offers the hypothesis that prion polypeptides are intrinsically predisposed to non-physiological folding conformations that would account for their environmental durability and persistent infectivity. Similarly, the avidity of binding and potency of prion infectivity from environmental sources also offers a recent hypothesis that prion polypeptides bound to soil minerals are actually more infectious than studies with purified polypeptides would predict. Since certain of the prion diseases have a history of epidemics in economically important animal species and have the potential to transmit to humans, urgency is attached to understanding the environmental transmission of prion diseases and the development of protocols for their containment and inactivation.
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Affiliation(s)
- Richard C Wiggins
- National Health and Environmental Effects Research Laboratory, US EPA/Office of Research and Development, MD B305-02, Research Triangle Park, NC 27711, USA.
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Erlich P, Cesbron JY, Lemaire-Vieille C, Curt A, Andrieu JP, Schoehn G, Jamin M, Gagnon J. PrP N-terminal domain triggers PrP(Sc)-like aggregation of Dpl. Biochem Biophys Res Commun 2007; 365:478-83. [PMID: 17997980 DOI: 10.1016/j.bbrc.2007.10.202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Accepted: 10/31/2007] [Indexed: 12/19/2022]
Abstract
Transmissible spongiform encephalopathies are fatal neurodegenerative disorders thought to be transmitted by self-perpetuating conformational conversion of a neuronal membrane glycoprotein (PrP(C), for "cellular prion protein") into an abnormal state (PrP(Sc), for "scrapie prion protein"). Doppel (Dpl) is a protein that shares significant biochemical and structural homology with PrP(C). In contrast to its homologue PrP(C), Dpl is unable to participate in prion disease progression or to achieve an abnormal PrP(Sc)-like state. We have constructed a chimeric mouse protein, composed of the N-terminal domain of PrP(C) (residues 23-125) and the C-terminal part of Dpl (residues 58-157). This chimeric protein displays PrP-like biochemical and structural features; when incubated in presence of NaCl, the alpha-helical monomer forms soluble beta-sheet-rich oligomers which acquire partial resistance to pepsin proteolysis in vitro, as do PrP oligomers. Moreover, the presence of aggregates akin to protofibrils is observed in soluble oligomeric species by electron microscopy.
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Affiliation(s)
- Paul Erlich
- Laboratoire Adaptation et Pathogénie des Micro-organismes, Université Joseph Fourier, BP 170, 38042 Grenoble Cedex 9, France
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Watts JC, Drisaldi B, Ng V, Yang J, Strome B, Horne P, Sy MS, Yoong L, Young R, Mastrangelo P, Bergeron C, Fraser PE, Carlson GA, Mount HTJ, Schmitt-Ulms G, Westaway D. The CNS glycoprotein Shadoo has PrP(C)-like protective properties and displays reduced levels in prion infections. EMBO J 2007; 26:4038-50. [PMID: 17703189 PMCID: PMC1950727 DOI: 10.1038/sj.emboj.7601830] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Accepted: 07/24/2007] [Indexed: 12/12/2022] Open
Abstract
The cellular prion protein, PrPC, is neuroprotective in a number of settings and in particular prevents cerebellar degeneration mediated by CNS-expressed Doppel or internally deleted PrP (‘ΔPrP'). This paradigm has facilitated mapping of activity determinants in PrPC and implicated a cryptic PrPC-like protein, ‘π'. Shadoo (Sho) is a hypothetical GPI-anchored protein encoded by the Sprn gene, exhibiting homology and domain organization similar to the N-terminus of PrP. Here we demonstrate Sprn expression and Sho protein in the adult CNS. Sho expression overlaps PrPC, but is low in cerebellar granular neurons (CGNs) containing PrPC and high in PrPC-deficient dendritic processes. In Prnp0/0 CGNs, Sho transgenes were PrPC-like in their ability to counteract neurotoxic effects of either Doppel or ΔPrP. Additionally, prion-infected mice exhibit a dramatic reduction in endogenous Sho protein. Sho is a candidate for π, and since it engenders a PrPC-like neuroprotective activity, compromised neuroprotective activity resulting from reduced levels may exacerbate damage in prion infections. Sho may prove useful in deciphering several unresolved facets of prion biology.
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Affiliation(s)
- Joel C Watts
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Bettina Drisaldi
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
| | - Vivian Ng
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
| | - Jing Yang
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
| | - Bob Strome
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
| | - Patrick Horne
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
| | - Man-Sun Sy
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Larry Yoong
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
| | | | - Peter Mastrangelo
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
| | - Catherine Bergeron
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Paul E Fraser
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | | | - Howard T J Mount
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
- Department of Medicine, University of Toronto, Toronto, Canada
| | - Gerold Schmitt-Ulms
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - David Westaway
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Alberta, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Room 116, Environmental Engineering Building, Edmonton, Alberta, Canada T6G 2M8. Tel.: +780 492 9377; Fax: +780 492 9352; E-mail:
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Sakudo A, Onodera T, Ikuta K. Prion protein gene-deficient cell lines: powerful tools for prion biology. Microbiol Immunol 2007; 51:1-13. [PMID: 17237594 DOI: 10.1111/j.1348-0421.2007.tb03877.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Prion diseases are zoonotic infectious diseases commonly transmissible among animals via prion infections with an accompanying deficiency of cellular prion protein (PrP(C)) and accumulation of an abnormal isoform of prion protein (PrP(Sc)), which are observed in neurons in the event of injury and disease. To understand the role of PrP(C) in the neuron in health and diseases, we have established an immortalized neuronal cell line HpL3-4 from primary hippocampal cells of prion protein (PrP) gene-deficient mice by using a retroviral vector encoding Simian Virus 40 Large T antigen (SV40 LTag). The HpL3-4 cells exhibit cell-type-specific proteins for the neuronal precursor lineage. Recently, this group and other groups have established PrP-deficient cell lines from many kinds of cell types including glia, fibroblasts and neuronal cells, which will have a broad range of applications in prion biology. In this review, we focus on recently obtained information about PrP functions and possible studies on prion infections using the PrPdeficient cell lines.
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Affiliation(s)
- Akikazu Sakudo
- Department of Virology, Research Institute for Microbial Diseases, Osaka University, Japan.
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Watts JC, Westaway D. The prion protein family: Diversity, rivalry, and dysfunction. Biochim Biophys Acta Mol Basis Dis 2007; 1772:654-72. [PMID: 17562432 DOI: 10.1016/j.bbadis.2007.05.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Revised: 04/26/2007] [Accepted: 05/02/2007] [Indexed: 11/24/2022]
Abstract
The prion gene family currently consists of three members: Prnp which encodes PrP(C), the precursor to prion disease associated isoforms such as PrP(Sc); Prnd which encodes Doppel, a testis-specific protein involved in the male reproductive system; and Sprn which encodes the newest PrP-like protein, Shadoo, which is expressed in the CNS. Although the identification of numerous candidate binding partners for PrP(C) has hinted at possible cellular roles, molecular interpretations of PrP(C) activity remain obscure and no widely-accepted view as to PrP(C) function has emerged. Nonetheless, studies into the functional interrelationships of prion proteins have revealed an interesting phenomenon: Doppel is neurotoxic to cerebellar cells in a manner which can be blocked by either PrP(C) or Shadoo. Further examination of this paradigm may help to shed light on two prominent unanswered questions in prion biology: the functional role of PrP(C) and the neurotoxic pathways initiated by PrP(Sc) in prion disease.
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Affiliation(s)
- Joel C Watts
- Centre for Research in Neurodegenerative Diseases and Department of Laboratory Medicine and Pathobiology, University of Toronto, Canada
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Nicolas O, Gavín R, Braun N, Ureña JM, Fontana X, Soriano E, Aguzzi A, del Río JA. Bcl‐2 overexpression delays caspase‐3 activation and rescues cerebellar degeneration in prion‐deficient mice that overexpress amino‐terminally truncated prion. FASEB J 2007; 21:3107-17. [PMID: 17494993 DOI: 10.1096/fj.06-7827com] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Prnp knockout mice that overexpress an amino-truncated form of PrPc (deltaPrP) are ataxic and display cerebellar cell loss and premature death. Studies on the molecular and intracellular events that trigger cell death in these mutants may contribute to elucidate the functions of PrPc and to the design of treatments for prion disease. Here we examined the effects of Bcl-2 overexpression in neurons on the development of the neurological syndrome and cerebellar pathology of deltaPrP. We show that deltaPrP overexpression activates the stress-associated kinases ERK1-2 in reactive astroglia, p38 and the phosphorylation of p53, which leads to the death of cerebellar neurons in mutant mice. We found that the expression of deltaPrP in cell lines expressing very low levels of PrPc strongly induces the activation of apoptotic pathways, thereby leading to caspase-3 activation and cell death, which can be prevented by coexpressing Bcl-2. Finally, we corroborate in vivo that neuronal-directed Bcl-2 overexpression in deltaPrP mice (deltaPrP Bcl-2) markedly reduces caspase-3 activation, glial activation, and neuronal cell death in cerebellum by improving locomotor deficits and life expectancy.
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Affiliation(s)
- Oriol Nicolas
- Department of Cell Biology, University of Barcelona, Barcelona, Spain
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Sakudo A, Nakamura I, Ikuta K, Onodera T. Recent Developments in Prion Disease Research: Diagnostic Tools and In Vitro Cell Culture Models. J Vet Med Sci 2007; 69:329-37. [PMID: 17485919 DOI: 10.1292/jvms.69.329] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
After prion infection, an abnormal isoform of prion protein (PrP(Sc)) converts the cellular isoform of prion protein (PrP(C)) into PrP(Sc). PrP(C)-to-PrP(Sc) conversion leads to PrP(Sc) accumulation and PrP(C) deficiency, contributing etiologically to induction of prion diseases. Presently, most of the diagnostic methods for prion diseases are dependent on PrP(Sc) detection. Highly sensitive/accurate specific detection of PrP(Sc) in many different samples is a prerequisite for attempts to develop reliable detection methods. Towards this goal, several methods have recently been developed to facilitate sensitive and precise detection of PrP(Sc), namely, protein misfolding cyclic amplification, conformation-dependent immunoassay, dissociation-enhanced lanthanide fluorescent immunoassay, capillary gel electrophoresis, fluorescence correlation spectroscopy, flow microbead immunoassay, etc. Additionally, functionally relevant prion-susceptible cell culture models that recognize the complexity of the mechanisms of prion infection have also been pursued, not only in relation to diagnosis, but also in relation to prion biology. Prion protein (PrP) gene-deficient neuronal cell lines that can clearly elucidate PrP(C) functions would contribute to understanding of the prion infection mechanism. In this review, we describe the trend in recent development of diagnostic methods and cell culture models for prion diseases and their potential applications in prion biology.
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Affiliation(s)
- Akikazu Sakudo
- Department of Molecular Immunology, School of Agricultural and Life Sciences, The University of Tokyo, Japan
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