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Adhikari UK, Sakiz E, Habiba U, Mikhael M, Senesi M, David MA, Guillemin GJ, Ooi L, Karl T, Collins S, Tayebi M. Treatment of microglia with Anti-PrP monoclonal antibodies induces neuronal apoptosis in vitro. Heliyon 2021; 7:e08644. [PMID: 35005289 PMCID: PMC8715334 DOI: 10.1016/j.heliyon.2021.e08644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/23/2021] [Accepted: 12/16/2021] [Indexed: 11/04/2022] Open
Abstract
Previous reports highlighted the neurotoxic effects caused by some motif-specific anti-PrPC antibodies in vivo and in vitro. In the current study, we investigated the detailed alterations of the proteome with liquid chromatography–mass spectrometry following direct application of anti-PrPC antibodies on mouse neuroblastoma cells (N2a) and mouse primary neuronal (MPN) cells or by cross-linking microglial PrPC with anti-PrPC antibodies prior to co-culture with the N2a/MPN cells. Here, we identified 4 (3 upregulated and 1 downregulated) and 17 (11 upregulated and 6 downregulated) neuronal apoptosis-related proteins following treatment of the N2a and N11 cell lines respectively when compared with untreated cells. In contrast, we identified 1 (upregulated) and 4 (2 upregulated and 2 downregulated) neuronal apoptosis-related proteins following treatment of MPN cells and N11 when compared with untreated cells. Furthermore, we also identified 3 (2 upregulated and 1 downregulated) and 2 (1 upregulated and 1 downregulated) neuronal apoptosis-related related proteins following treatment of MPN cells and N11 when compared to treatment with an anti-PrP antibody that lacks binding specificity for mouse PrP. The apoptotic effect of the anti-PrP antibodies was confirmed with flow cytometry following labelling of Annexin V-FITC. The toxic effects of the anti-PrP antibodies was more intense when antibody-treated N11 were co-cultured with the N2a and the identified apoptosis proteome was shown to be part of the PrPC-interactome. Our observations provide a new insight into the prominent role played by microglia in causing neurotoxic effects following treatment with anti-PrPC antibodies and might be relevant to explain the antibody mediated toxicity observed in other related neurodegenerative diseases such as Alzheimer. Antibody cross-linking neuronal PrPC induces apoptosis. Antibody cross-linking microglial PrPC induces neuronal apoptosis. Different apoptotic pathways were triggered by specific anti-PrP antibody treatments.
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Colini Baldeschi A, Vanni S, Zattoni M, Legname G. Novel regulators of PrP C expression as potential therapeutic targets in prion diseases. Expert Opin Ther Targets 2020; 24:759-776. [PMID: 32631090 DOI: 10.1080/14728222.2020.1782384] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Prion diseases are rare and fatal neurodegenerative disorders. The key molecular event in these disorders is the misfolding of the physiological form of the cellular prion protein, PrPC, leading to the accumulation of a pathological isoform, PrPSc, with unique features. Both isoforms share the same primary sequence, lacking detectable differences in posttranslational modification, a major hurdle for their biochemical or biophysical independent characterization. The mechanism underlying the conversion of PrPC to PrPSc is not completely understood, so finding an effective therapy to cure prion disorders is extremely challenging. AREAS COVERED This review discusses the strategies for decreasing prion replication and throws a spotlight on the relevance of PrPC in the prion accumulation process. EXPERT OPINION PrPC is the key substrate for prion pathology; hence, the most promising therapeutic approach appears to be the targeting of PrPC to block the production of the infectious isoform. The use of RNA interference and antisense oligonucleotide technologies may offer opportunities for treatment because of their success in clinical trials for other neurodegenerative diseases.
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Affiliation(s)
- Arianna Colini Baldeschi
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore Di Studi Avanzati (SISSA) , Trieste, Italy
| | - Silvia Vanni
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per Lo Studio E La Cura Dei Tumori (IRST) IRCCS , Meldola, Italy
| | - Marco Zattoni
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore Di Studi Avanzati (SISSA) , Trieste, Italy
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore Di Studi Avanzati (SISSA) , Trieste, Italy
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Holec SA, Block AJ, Bartz JC. The role of prion strain diversity in the development of successful therapeutic treatments. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:77-119. [PMID: 32958242 PMCID: PMC8939712 DOI: 10.1016/bs.pmbts.2020.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Prions are a self-propagating misfolded conformation of a cellular protein. Prions are found in several eukaryotic organisms with mammalian prion diseases encompassing a wide range of disorders. The first recognized prion disease, the transmissible spongiform encephalopathies (TSEs), affect several species including humans. Alzheimer's disease, synucleinopathies, and tauopathies share a similar mechanism of self-propagation of the prion form of the disease-specific protein reminiscent of the infection process of TSEs. Strain diversity in prion disease is characterized by differences in the phenotype of disease that is hypothesized to be encoded by strain-specific conformations of the prion form of the disease-specific protein. Prion therapeutics that target the prion form of the disease-specific protein can lead to the emergence of drug-resistant strains of prions, consistent with the hypothesis that prion strains exist as a dynamic mixture of a dominant strain in combination with minor substrains. To overcome this obstacle, therapies that reduce or eliminate the template of conversion are efficacious, may reverse neuropathology, and do not result in the emergence of drug resistance. Recent advancements in preclinical diagnosis of prion infection may allow for a combinational approach that treats the prion form and the precursor protein to effectively treat prion diseases.
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Affiliation(s)
- Sara A.M. Holec
- Institute for Applied Life Sciences and Department of Biology, University of Massachusetts Amherst, Amherst, MA, United States,Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE, United States
| | - Alyssa J. Block
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE, United States
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE, United States,Corresponding author:
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Abskharon R, Wang F, Wohlkonig A, Ruan J, Soror S, Giachin G, Pardon E, Zou W, Legname G, Ma J, Steyaert J. Structural evidence for the critical role of the prion protein hydrophobic region in forming an infectious prion. PLoS Pathog 2019; 15:e1008139. [PMID: 31815959 PMCID: PMC6922452 DOI: 10.1371/journal.ppat.1008139] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 12/19/2019] [Accepted: 10/09/2019] [Indexed: 11/18/2022] Open
Abstract
Prion or PrPSc is the proteinaceous infectious agent causing prion diseases in various mammalian species. Despite decades of research, the structural basis for PrPSc formation and prion infectivity remains elusive. To understand the role of the hydrophobic region in forming infectious prion at the molecular level, we report X-ray crystal structures of mouse (Mo) prion protein (PrP) (residues 89-230) in complex with a nanobody (Nb484). Using the recombinant prion propagation system, we show that the binding of Nb484 to the hydrophobic region of MoPrP efficiently inhibits the propagation of proteinase K resistant PrPSc and prion infectivity. In addition, when added to cultured mouse brain slices in high concentrations, Nb484 exhibits no neurotoxicity, which is drastically different from other neurotoxic anti-PrP antibodies, suggesting that the Nb484 can be a potential therapeutic agent against prion disease. In summary, our data provides the first structure-function evidence supporting a crucial role of the hydrophobic region of PrP in forming an infectious prion.
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Affiliation(s)
- Romany Abskharon
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- VIB-VUB Center for Structural Biology, Vlaams Instituut Biotechnologie (VIB), Brussels, Belgium
- Center for Neurodegenerative Science, Van Andel Institute, Grand Rapids, Michigan, United States of America
- National Institute of Oceanography and Fisheries (NIOF), Cairo, Egypt
| | - Fei Wang
- Center for Neurodegenerative Science, Van Andel Institute, Grand Rapids, Michigan, United States of America
- * E-mail: (FW); (JM); (JS)
| | - Alexandre Wohlkonig
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- VIB-VUB Center for Structural Biology, Vlaams Instituut Biotechnologie (VIB), Brussels, Belgium
| | - Juxin Ruan
- Center for Neurodegenerative Science, Van Andel Institute, Grand Rapids, Michigan, United States of America
| | - Sameh Soror
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- VIB-VUB Center for Structural Biology, Vlaams Instituut Biotechnologie (VIB), Brussels, Belgium
- Center of Excellence, Helwan Structural Biology Research, Faculty of Pharmacy, Helwan University, Cairo, Egypt
| | - Gabriele Giachin
- Structural Biology Group, European Synchrotron Radiation Facility, Grenoble, France
| | - Els Pardon
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- VIB-VUB Center for Structural Biology, Vlaams Instituut Biotechnologie (VIB), Brussels, Belgium
| | - Wenquan Zou
- Departments of Pathology and Neurology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Jiyan Ma
- Center for Neurodegenerative Science, Van Andel Institute, Grand Rapids, Michigan, United States of America
- * E-mail: (FW); (JM); (JS)
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- VIB-VUB Center for Structural Biology, Vlaams Instituut Biotechnologie (VIB), Brussels, Belgium
- * E-mail: (FW); (JM); (JS)
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Redaelli V, Tagliavini F, Moda F. Clinical features, pathophysiology and management of fatal familial insomnia. Expert Opin Orphan Drugs 2017. [DOI: 10.1080/21678707.2017.1311251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Amphotericin B Increases Transglutaminase 2 Expression Associated with Upregulation of Endocytotic Activity in Mouse Microglial Cell Line BV-2. Neurochem Res 2017; 42:1488-1495. [PMID: 28224343 DOI: 10.1007/s11064-017-2205-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/06/2017] [Accepted: 02/09/2017] [Indexed: 12/14/2022]
Abstract
Amphotericin B (AmB), a polyene antibiotic, is reported to cause the microglial activation to induce nitric oxide (NO) production and proinflammatory cytokines expression, and change neurotrophic factors expression in cultured microglia (Motoyoshi et al. in Neurochem Int 52:1290-1296, 2008). On the other hand, tissue-type transglutaminase (TG2) is involved in connection to phagocytes with apoptotic cells. Engulfment of neurons by activated microglia is thought to cause neurodegenerative diseases but detail is unclear, and involvement of TG2 in phagocytosis has been reported in our previous study using lipopolysaccharide-stimulated BV-2 cells (Kawabe et al. in Neuroimmunomodulation 22(4):243-249, 2015). In the present study, we examined the changes of TG2 expression, phagocytosis and pinocytosis in BV-2 cells stimulated by AmB. AmB stimulation increased TG2 expression and TG activity. Phagocytosis of dead cells and pinocytosis of fluorescent microbeads were also up-regulated by AmB stimulation in BV-2 cells. Blockade of TG activity by cystamine, an inhibitor of TGs, suppressed AmB-enhanced TG2 expression, TG activity, NO production, phagocytosis and pinocytosis. Excessive NO production from microglia and/or facilitation of phagocytosis might be involved in neuronal death. To control TG activity might make possible to protect neurons and care for CNS diseases.
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Abstract
Since the term protein was first coined in 1838 and protein was discovered to be the essential component of fibrin and albumin, all cellular proteins were presumed to play beneficial roles in plants and mammals. However, in 1967, Griffith proposed that proteins could be infectious pathogens and postulated their involvement in scrapie, a universally fatal transmissible spongiform encephalopathy in goats and sheep. Nevertheless, this novel hypothesis had not been evidenced until 1982, when Prusiner and coworkers purified infectious particles from scrapie-infected hamster brains and demonstrated that they consisted of a specific protein that he called a "prion." Unprecedentedly, the infectious prion pathogen is actually derived from its endogenous cellular form in the central nervous system. Unlike other infectious agents, such as bacteria, viruses, and fungi, prions do not contain genetic materials such as DNA or RNA. The unique traits and genetic information of prions are believed to be encoded within the conformational structure and posttranslational modifications of the proteins. Remarkably, prion-like behavior has been recently observed in other cellular proteins-not only in pathogenic roles but also serving physiological functions. The significance of these fascinating developments in prion biology is far beyond the scope of a single cellular protein and its related disease.
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Motoyoshi-Yamashiro A, Takano K, Kawabe K, Izawa T, Nakajima H, Moriyama M, Nakamura Y. Amphotericin B induces glial cell line-derived neurotrophic factor in the rat brain. J Vet Med Sci 2014; 76:1353-8. [PMID: 25283947 PMCID: PMC4221168 DOI: 10.1292/jvms.14-0160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Amphotericin B (AmB) is a
polyene antifungal drug and is reported to be one of a few reagents having therapeutic
effects on prion diseases, that is, a delay in the appearance of clinical signs and
prolongation of the survival time in an animal model. In prion diseases, glial cells have
been suggested to play important roles; however, the therapeutic mechanism of AmB on prion
diseases remains elusive. We have previously reported that AmB changed the expression of
neurotrophic factors in microglia and astrocytes (Motoyoshi et al., 2008,
Neurochem. Int. 52, 1290–1296; Motoyoshi-Yamashiro et
al., 2013, ibid. 63, 93–100). These results suggested that
neurotrophic factors derived from glial cells might be involved in the therapeutic
mechanism of AmB. In the present study, we examined immunohistochemically the effects of
AmB on the expression of neurotrophic factors in the rat brain. We found that direct
injection of AmB into the striatum significantly enhanced the expression of glial cell
line-derived neurotrophic factor protein. Amphotericin B also increased the expressions of
CD11b and glial fibrillary acidic protein, markers of microglia and astrocytes,
respectively. Moreover, expressions of the two neurotrophic factors by AmB were
co-localized with the expression of CD11b or glial fibrillary acidic protein. These
results suggest that AmB in vivo might also activate glial cells and
induce the production of neurotrophic factors protecting neurons in prion diseases.
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Affiliation(s)
- Akiko Motoyoshi-Yamashiro
- Laboratory of Integrative Physiology in Veterinary Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka 598-8531, Japan
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Motoyoshi-Yamashiro A, Tamura M, Moriyama M, Takano K, Kawabe K, Nakajima H, Katoh-Semba R, Furuichi T, Nakamura Y. Activation of cultured astrocytes by amphotericin B: stimulation of NO and cytokines production and changes in neurotrophic factors production. Neurochem Int 2013; 63:93-100. [PMID: 23727061 DOI: 10.1016/j.neuint.2013.05.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 04/30/2013] [Accepted: 05/19/2013] [Indexed: 11/17/2022]
Abstract
Amphotericin B (AmB) is a polyene antibiotic and reported to be one of a few reagents having therapeutic effects on prion diseases, such as the delay in the appearing of the clinical signs and the prolongation of the survival time. In prion diseases, glial cells have been suggested to play important roles by proliferating and producing various factors such as nitric oxide, proinflammatory cytokines, and neurotrophic factors. However, the therapeutic mechanism of AmB on prion diseases remains elusive. We have previously reported that AmB changed the expression of neurotoxic and neurotrophic factors in microglia (Motoyoshi et al., 2008, Neurochem. Int. 52, 1290-1296). In the present study, we examined the effects of AmB on cellular functions of rat cultured astrocytes. We found that AmB could activate astrocytes to produce nitric oxide via inducible nitric oxide synthase induction. AmB also induced mRNA expression of interleukin-1β and tumor necrosis factor-α, and productions of their proteins in astrocytes. Moreover, AmB changed levels of neurotrophic factor mRNAs and proteins. Among three neurotrophic factors examined here, neurotrophin-3 mRNA expression and its protein production in the cells were down-regulated by AmB stimulation. On the other hand, AmB significantly enhanced the amounts of glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor proteins in the cells and the medium. These results suggest that AmB might show therapeutic effects on prion diseases by controlling the expression and production of such mediators in astrocytes.
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Affiliation(s)
- Akiko Motoyoshi-Yamashiro
- Laboratory of Integrative Physiology in Veterinary Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Japan
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Stanton JB, Schneider DA, Dinkel KD, Balmer BF, Baszler TV, Mathison BA, Boykin DW, Kumar A. Discovery of a novel, monocationic, small-molecule inhibitor of scrapie prion accumulation in cultured sheep microglia and Rov cells. PLoS One 2012; 7:e51173. [PMID: 23226483 PMCID: PMC3511409 DOI: 10.1371/journal.pone.0051173] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 10/30/2012] [Indexed: 11/24/2022] Open
Abstract
Prion diseases, including sheep scrapie, are neurodegenerative diseases with the fundamental pathogenesis involving conversion of normal cellular prion protein (PrPC) to disease-associated prion protein (PrPSc). Chemical inhibition of prion accumulation is widely investigated, often using rodent-adapted prion cell culture models. Using a PrPSc-specific ELISA we discovered a monocationic phenyl-furan-benzimidazole (DB772), which has previously demonstrated anti-pestiviral activity and represents a chemical category previously untested for anti-prion activity, that inhibited PrPSc accumulation and prion infectivity in primary sheep microglial cell cultures (PRNP 136VV/154RR/171QQ) and Rov9 cultures (VRQ-ovinized RK13 cells). We investigated potential mechanisms of this anti-prion activity by evaluating PrPC expression with quantitative RT-PCR and PrP ELISA, comparing the concentration-dependent anti-prion and anti-pestiviral effects of DB772, and determining the selectivity index. Results demonstrate at least an approximate two-log inhibition of PrPSc accumulation in the two cell systems and confirmed that the inhibition of PrPSc accumulation correlates with inhibition of prion infectivity. PRNP transcripts and total PrP protein concentrations within cell lysates were not decreased; thus, decreased PrPC expression is not the mechanism of PrPSc inhibition. PrPSc accumulation was multiple logs more resistant than pestivirus to DB772, suggesting that the anti-PrPSc activity was independent of anti-pestivirus activity. The anti-PrPSc selectivity index in cell culture was approximately 4.6 in microglia and 5.5 in Rov9 cells. The results describe a new chemical category that inhibits ovine PrPSc accumulation in primary sheep microglia and Rov9 cells, and can be used for future studies into the treatment and mechanism of prion diseases.
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Affiliation(s)
- James B Stanton
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA.
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11
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Mukherjee A, Morales-Scheihing D, Gonzalez-Romero D, Green K, Taglialatela G, Soto C. Calcineurin inhibition at the clinical phase of prion disease reduces neurodegeneration, improves behavioral alterations and increases animal survival. PLoS Pathog 2010; 6:e1001138. [PMID: 20949081 PMCID: PMC2951383 DOI: 10.1371/journal.ppat.1001138] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 09/08/2010] [Indexed: 11/19/2022] Open
Abstract
Prion diseases are fatal neurodegenerative disorders characterized by a long pre-symptomatic phase followed by rapid and progressive clinical phase. Although rare in humans, the unconventional infectious nature of the disease raises the potential for an epidemic. Unfortunately, no treatment is currently available. The hallmark event in prion diseases is the accumulation of a misfolded and infectious form of the prion protein (PrP(Sc)). Previous reports have shown that PrP(Sc) induces endoplasmic reticulum stress and changes in calcium homeostasis in the brain of affected individuals. In this study we show that the calcium-dependent phosphatase Calcineurin (CaN) is hyperactivated both in vitro and in vivo as a result of PrP(Sc) formation. CaN activation mediates prion-induced neurodegeneration, suggesting that inhibition of this phosphatase could be a target for therapy. To test this hypothesis, prion infected wild type mice were treated intra-peritoneally with the CaN inhibitor FK506 at the clinical phase of the disease. Treated animals exhibited reduced severity of the clinical abnormalities and increased survival time compared to vehicle treated controls. Treatment also led to a significant increase in the brain levels of the CaN downstream targets pCREB and pBAD, which paralleled the decrease of CaN activity. Importantly, we observed a lower degree of neurodegeneration in animals treated with the drug as revealed by a higher number of neurons and a lower quantity of degenerating nerve cells. These changes were not dependent on PrP(Sc) formation, since the protein accumulated in the brain to the same levels as in the untreated mice. Our findings contribute to an understanding of the mechanism of neurodegeneration in prion diseases and more importantly may provide a novel strategy for therapy that is beneficial at the clinical phase of the disease.
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Affiliation(s)
- Abhisek Mukherjee
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, Texas, United States of America
- Department of Neurology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Diego Morales-Scheihing
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, Texas, United States of America
| | - Dennisse Gonzalez-Romero
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, Texas, United States of America
- Department of Neurology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Kristi Green
- Department of Neurology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Giulio Taglialatela
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Claudio Soto
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, Texas, United States of America
- Department of Neurology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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A camelid anti-PrP antibody abrogates PrP replication in prion-permissive neuroblastoma cell lines. PLoS One 2010; 5:e9804. [PMID: 20339552 PMCID: PMC2842437 DOI: 10.1371/journal.pone.0009804] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 02/26/2010] [Indexed: 11/19/2022] Open
Abstract
The development of antibodies effective in crossing the blood brain barrier (BBB), capable of accessing the cytosol of affected cells and with higher affinity for PrPSc would be of paramount importance in arresting disease progression in its late stage and treating individuals with prion diseases. Antibody-based therapy appears to be the most promising approach following the exciting report from White and colleagues, establishing the “proof-of-principle” for prion-immunotherapy. After passive transfer, anti-prion antibodies were shown to be very effective in curing peripheral but not central rodent prion disease, due to the fact that these anti-prion antibodies are relatively large molecules and cannot therefore cross the BBB. Here, we show that an anti-prion antibody derived from camel immunised with murine scrapie material adsorbed to immunomagnetic beads is able to prevent infection of susceptible N2a cells and cure chronically scrapie-infected neuroblastoma cultures. This antibody was also shown to transmigrate across the BBB and cross the plasma membrane of neurons to target cytosolic PrPC. In contrast, treatment with a conventional anti-prion antibody derived from mouse immunised with recombinant PrP protein was unable to prevent recurrence of PrPSc replication. Furthermore, our camelid antibody did not display any neurotoxic effects following treatment of susceptible N2a cells as evidenced by TUNEL staining. These findings demonstrate the potential use of anti-prion camelid antibodies for the treatment of prion and other related diseases via non-invasive means.
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Abstract
The transmissible spongiform encephalopathies are rapidly progressive and invariably fatal neurodegenerative diseases for which there are no proven efficacious treatments. Many approaches have been undertaken to find ways to prevent, halt, or reverse these prion diseases, with limited success to date. However, as both our understanding of pathogenesis and our ability to detect early disease increases, so do our potential therapeutic targets and our chances of finding effective drugs. There is increasing pressure to find effective decontaminants for blood supplies, as variant Creutzfeldt Jakob Disease (vCJD) has been shown to be transmissible by blood, and to find non-toxic preventative therapies, with ongoing cases of Bovine Spongiform Encephalopathy (BSE) and the spread of Chronic Wasting Disease (CWD). Within the realm of chemotherapeutic approaches, much research has focussed on blocking the conversion of the normal form of prion protein (PrP(c)) to its abnormal counterpart (PrP(res)). Structurally, these chemotherapeutic agents are often polyanionic or polycyclic and may directly bind PrP(c) or PrP(res), or act by redistributing, sequestering, or down-regulating PrP(c), thus preventing its conversion. There are also some polycationic compounds which proport to enhance the clearance of PrP(res). Other targets include accessory molecules such as the laminin receptor precursor which influences conversion, or cell signalling molecules which may be required for pathogenesis. Of recent interest are the possible neuroprotective effects of some drugs. Importantly, there is evidence that combining compounds may provide synergistic responses. This review provides an update on current testing methods, therapeutic targets, and promising candidates for chemical-based therapy.
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Affiliation(s)
- Valerie L Sim
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.
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Béranger F, Crozet C, Goldsborough A, Lehmann S. Trehalose impairs aggregation of PrPSc molecules and protects prion-infected cells against oxidative damage. Biochem Biophys Res Commun 2008; 374:44-8. [PMID: 18602368 DOI: 10.1016/j.bbrc.2008.06.094] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Accepted: 06/21/2008] [Indexed: 01/09/2023]
Abstract
Neurodegenerative disorders such as Alzheimer's, Huntington's, and prion diseases are characterized by abnormal protein deposits in the brain of affected patients. In prion diseases, a key event in the pathogenesis is the conversion of the normal prion protein (PrP(c)) into abnormal protease resistant PrP(Sc) deposits, a phenomenon associated with a higher sensitivity to oxidative stress in vitro. In cellular models of Alzheimer and Huntington diseases, the disaccharide trehalose has been shown to be effective in inhibiting huntingtin and Abeta peptide aggregates and reducing their associated toxicity. We show in this study that trehalose treatment of prion-infected cells decreases the size of de novo produced PrP(Sc) aggregates and modify their subcellular localization. Despite the fact that trehalose does not modify the protease resistance properties of PrP(Sc) molecules, it significantly protects prion-infected cells from induced oxidative damage, suggesting that this compound is of therapeutic interest.
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Affiliation(s)
- Florence Béranger
- Institut de Génétique Humaine, UPR CNRS1142, 141 Rue de Cardonille, 34396 Montpellier Cedex 5, France.
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De Luigi A, Colombo L, Diomede L, Capobianco R, Mangieri M, Miccolo C, Limido L, Forloni G, Tagliavini F, Salmona M. The efficacy of tetracyclines in peripheral and intracerebral prion infection. PLoS One 2008; 3:e1888. [PMID: 18365024 PMCID: PMC2268013 DOI: 10.1371/journal.pone.0001888] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 02/23/2008] [Indexed: 11/18/2022] Open
Abstract
We have previously shown that tetracyclines interact with and reverse the protease resistance of pathological prion protein extracted from scrapie-infected animals and patients with all forms of Creutzfeldt-Jakob disease, lowering the prion titre and prolonging survival of cerebrally infected animals. To investigate the effectiveness of these drugs as anti-prion agents Syrian hamsters were inoculated intramuscularly or subcutaneously with 263K scrapie strain at a 10−4 dilution. Tetracyclines were injected intramuscularly or intraperitoneally at the dose of 10 mg/kg. A single intramuscular dose of doxycycline one hour after infection in the same site of inoculation prolonged median survival by 64%. Intraperitoneal doses of tetracyclines every two days for 40 or 44 days increased survival time by 25% (doxycycline), 32% (tetracycline); and 81% (minocycline) after intramuscular infection, and 35% (doxycycline) after subcutaneous infection. To extend the therapeutic potential of tetracyclines, we investigated the efficacy of direct infusion of tetracyclines in advanced infection. Since intracerebroventricular infusion of tetracycline solutions can cause overt acute toxicity in animals, we entrapped the drugs in liposomes. Animals were inoculated intracerebrally with a 10−4 dilution of the 263K scrapie strain. A single intracerebroventricular infusion of 25 µg/ 20 µl of doxycycline or minocycline entrapped in liposomes was administered 60 days after inoculation, when 50% of animals showed initial symptoms of the disease. Median survival increased of 8.1% with doxycycline and 10% with minocycline. These data suggest that tetracyclines might have therapeutic potential for humans.
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Affiliation(s)
- Ada De Luigi
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche “Mario Negri”, Milano, Italy
| | - Laura Colombo
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche “Mario Negri”, Milano, Italy
| | - Luisa Diomede
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche “Mario Negri”, Milano, Italy
| | | | - Michela Mangieri
- Fondazione I.R.C.C.S. Istituto Neurologico “Carlo Besta”, Milano, Italy
| | - Claudia Miccolo
- Fondazione I.R.C.C.S. Istituto Neurologico “Carlo Besta”, Milano, Italy
| | - Lucia Limido
- Fondazione I.R.C.C.S. Istituto Neurologico “Carlo Besta”, Milano, Italy
| | - Gianluigi Forloni
- Department of Neuroscience, Istituto di Ricerche Farmacologiche “Mario Negri”, Milano, Italy
| | | | - Mario Salmona
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche “Mario Negri”, Milano, Italy
- * E-mail:
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16
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Motoyoshi A, Nakajima H, Takano K, Moriyama M, Kannan Y, Nakamura Y. Effects of Amphotericin B on the expression of neurotoxic and neurotrophic factors in cultured microglia. Neurochem Int 2008; 52:1290-6. [PMID: 18328601 DOI: 10.1016/j.neuint.2008.01.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 01/18/2008] [Accepted: 01/24/2008] [Indexed: 12/01/2022]
Abstract
Amphotericin B (AmB) is a polyene antibiotic and reported to have therapeutic effects on prion diseases, in which the microglial activation has been suggested to play important roles by proliferating and producing various factors such as nitric oxide, proinflammatory cytokines, and so on. However, the therapeutic mechanism of AmB on prion diseases remains elusive. In the present study, we investigated the effects of AmB on cellular functions of rat primary cultured microglia. We found that AmB, similarly as lipopolysaccharide (LPS), could activate microglia to produce nitric oxide via inducible nitric oxide synthase. Both AmB and LPS also induced mRNA expressions of interleukin-1beta, interleukin-6, and tumor necrosis factor-alpha in microglia. AmB also changed the expression levels of neurotrophic factors mRNAs. AmB and LPS significantly down-regulated the level of ciliary neurotrophic factor mRNA. However, AmB, but not LPS, significantly up-regulated the level of glial cell-line derived neurotrophic factor mRNA in microglia. In addition, brain-derived neurotrophic factor mRNA expression level was tending upward by treatment with AmB, but not with LPS. Taken together, these results suggest that AmB regulates the microglial activation in different manner from LPS and that microglia may participate in the therapeutic effects of AmB on prion diseases by controlling the expression and production of such mediators.
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Affiliation(s)
- Akiko Motoyoshi
- Laboratory of Integrative Physiology in Veterinary Sciences, Osaka Prefecture University 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
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17
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Kocisko DA, Engel AL, Harbuck K, Arnold KM, Olsen EA, Raymond LD, Vilette D, Caughey B. Comparison of protease-resistant prion protein inhibitors in cell cultures infected with two strains of mouse and sheep scrapie. Neurosci Lett 2005; 388:106-11. [PMID: 16039063 DOI: 10.1016/j.neulet.2005.06.053] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Revised: 06/14/2005] [Accepted: 06/23/2005] [Indexed: 11/25/2022]
Abstract
The transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative diseases. A primary therapeutic target for TSE intervention has been a protease-resistant form of prion protein known as PrP(Sc) or PrP-res. In vitro testing of mouse scrapie-infected cell cultures has identified many PrP-res inhibitors that also have activity in vivo. Here we identify 32 new inhibitors of two strains of mouse scrapie PrP-res. Furthermore, to investigate the species-specificity of these and other PrP-res inhibitors, we have developed a high-throughput cell culture assay based on Rov9 cells chronically-infected with sheep scrapie. Of 32 inhibitors of murine PrP-res that were also tested in the Rov9 cells, only six showed inhibitory activity against sheep PrP-res. The three most potent inhibitors of both murine and ovine PrP-res formation (with 50% inhibition at < or =5 microM) were tannic acid, pentosan polysulfate and Fe(III) deuteroporphyrin 2,4-bisethyleneglycol. The latter two have anti-mouse scrapie activity in vivo. These results identify new inhibitors of murine and ovine PrP-res formation and reinforce the idea that compounds effective against PrP-res from one species or strain cannot be assumed to be active against others.
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Affiliation(s)
- David A Kocisko
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.
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18
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Abstract
Devising approaches to the therapy of transmissible spongiform encephalopathies, or prion diseases, is beset by many difficulties. For one, the nature of the infectious agent, the prion, is understood only in outline, and its composition, structure, and mode of replication are still shrouded in mystery. In addition, the mechanism of pathogenesis is not well understood. Because clinical disease affects mainly the brain parenchyme, therapeutic agents must be able to traverse the brain-blood barrier (BBB) or have to be introduced directly into the cerebrospinal fluid or brain tissue. And finally, because the disease is usually recognized only after onset of severe clinical symptoms, the question arises as to whether the neurodegenerative processes can be reversed to any extent after a successful eradication of the agent.
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Affiliation(s)
- Charles Weissmann
- Department of Neurodegenerative Disease/MRC Prion Unit, Institute of Neurology, Queen Square, London WC1N 3BG, UK.
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19
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Abstract
The transmissible spongiform encephalopathies could represent a new mode of transmission for infectious diseases--a process more akin to crystallization than to microbial replication. The prion hypothesis proposes that the normal isoform of the prion protein is converted to a disease-specific species by template-directed misfolding. Therapeutic and prophylactic strategies to combat these diseases have emerged from immunological and chemotherapeutic approaches. The lessons learned in treating prion disease will almost certainly have an impact on other diseases that are characterized by the pathological accumulation of misfolded proteins.
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Affiliation(s)
- Neil R Cashman
- Centre for Research in Neurodegenerative Diseases, University of Toronto, 6 Queen's Park Crescent West, Toronto, Ontario M553H2, Canada.
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20
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Boshuizen RS, Langeveld JPM, Salmona M, Williams A, Meloen RH, Langedijk JPM. An in vitro screening assay based on synthetic prion protein peptides for identification of fibril-interfering compounds. Anal Biochem 2004; 333:372-80. [PMID: 15450815 DOI: 10.1016/j.ab.2004.06.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2004] [Indexed: 11/23/2022]
Abstract
Transmissible spongiform encephalopathies are neurodegenerative diseases and are considered to be caused by malformed prion proteins accumulated into fibrillar structures that can then aggregate to form larger deposits or amyloid plaques. The identification of fibril-interfering compounds is of therapeutic and prophylactic interest. A robust and easy-to-perform, high-throughput, in vitro fluorescence assay was developed for the detection of such compounds. The assay was based on staining with the fluorescent probe thioflavin S in polystyrene microtiter plates to determine the amyloid state of synthetic peptides, representing a putative transmembrane domain of human and mouse prion protein. In determining optimal test conditions, it was found that drying peptides from phosphate buffer prior to staining resulted in good reproducibility with an interassay variation coefficient of 8%. Effects of thioflavin S concentration and staining time were established. At optimal thioflavin S concentration of 0.2mg/ml, the fluorescence signals of thioflavin S with five different prion protein-based fibrillogenic peptides, as well as peptide Abeta((1-42)), were found to show a peptide-dependent linear correlation within a peptide concentration range of 10-400 microM. The ability of the assay to identify compounds that interfere with fibril formation and/or dissociate preformed fibrils was demonstrated for tetracyclic compounds by preceding coincubation with human prion protein peptide huPrP106-126.
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Affiliation(s)
- Ronald S Boshuizen
- Pepscan Systems B.V., Edelhertweg 15, 8219 PH Lelystad, The Netherlands.
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21
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Shaked GM, Engelstein R, Avraham I, Kahana E, Gabizon R. Dimethyl sulfoxide delays PrP sc accumulation and disease symptoms in prion-infected hamsters. Brain Res 2003; 983:137-43. [PMID: 12914974 DOI: 10.1016/s0006-8993(03)03045-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PrP(Sc), an aberrantly folded protein, is the only identified component of the prion, an agent causing fatal neurodegenerative diseases such as scrapie and bovine spongiform encephalopathy. Dimethyl sulfoxide (DMSO) has been shown to reduce the accumulation of PrP(Sc) in scrapie-infected (ScN2a) cells, and to inhibit its aggregation in vitro. In humans, DMSO was used successfully in the treatment of various peripheral amyloidotic diseases. Here we show that administration of DMSO to scrapie-infected hamsters significantly prolonged disease incubation time, as well as delayed the accumulation of PrP(Sc) in Syrian hamster brains. Interestingly, administration of DMSO to scrapie sick hamsters resulted in increased clearance of protease-resistant PrP in their urine. We conclude that although DMSO by itself may not be sufficient to cure prion diseases, it may be considered as a component in a 'cocktail' drug approach for these disorders. Also, urine PrP testing should be considered for the assessment of treatment efficacy.
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Affiliation(s)
- Gideon M Shaked
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah University Hospital, 91120, Jerusalem, Israel
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22
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Barret A, Tagliavini F, Forloni G, Bate C, Salmona M, Colombo L, De Luigi A, Limido L, Suardi S, Rossi G, Auvré F, Adjou KT, Salès N, Williams A, Lasmézas C, Deslys JP. Evaluation of quinacrine treatment for prion diseases. J Virol 2003; 77:8462-9. [PMID: 12857915 PMCID: PMC165262 DOI: 10.1128/jvi.77.15.8462-8469.2003] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Based on in vitro observations in scrapie-infected neuroblastoma cells, quinacrine has recently been proposed as a treatment for Creutzfeldt-Jakob disease (CJD), including a new variant CJD which is linked to contamination of food by the bovine spongiform encephalopathy (BSE) agent. The present study investigated possible mechanisms of action of quinacrine on prions. The ability of quinacrine to interact with and to reduce the protease resistance of PrP peptide aggregates and PrPres of human and animal origin were analyzed, together with its ability to inhibit the in vitro conversion of the normal prion protein (PrPc) to the abnormal form (PrPres). Furthermore, the efficiencies of quinacrine and chlorpromazine, another tricyclic compound, were examined in different in vitro models and in an experimental murine model of BSE. Quinacrine efficiently hampered de novo generation of fibrillogenic prion protein and PrPres accumulation in ScN2a cells. However, it was unable to affect the protease resistance of preexisting PrP fibrils and PrPres from brain homogenates, and a "curing" effect was obtained in ScGT1 cells only after lengthy treatment. In vivo, no detectable effect was observed in the animal model used, consistent with other recent studies and preliminary observations in humans. Despite its ability to cross the blood-brain barrier, the use of quinacrine for the treatment of CJD is questionable, at least as a monotherapy. The multistep experimental approach employed here could be used to test new therapeutic regimes before their use in human trials.
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Affiliation(s)
- A Barret
- Commissariat à l'Energie Atomique, 92265 Fontenay-aux-Roses, France
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23
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Hartsel SC, Weiland TR. Amphotericin B binds to amyloid fibrils and delays their formation: a therapeutic mechanism? Biochemistry 2003; 42:6228-33. [PMID: 12755626 DOI: 10.1021/bi0270384] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The membrane-active antifungal agent amphotericin B (AmB) is one of the few agents shown to slow the course of prion diseases in animals. Congo Red and other small molecules have been reported to directly inhibit amyloidogenesis in both prion and Alzheimer peptide model systems via specific binding. We propose that it is possible that AmB may act similarly to physically prevent conversion of the largely alpha-helical prion protein (PrP) to the pathological beta-sheet aggregate protease-resistant isoform (PrP(res)) in prion disease and by analogy prevent fibrillization in amyloid diseases. To assess whether AmB is capable of binding specifically to amyloid fibrils as does Congo Red, we have used the insulin fibril and Abeta 25-35 amyloid model fibril system. We find that AmB does bind strongly to both insulin (K(d) = 1.1 microM) and Abeta 25-35 amyloid (K(d) = 6.4 microM) fibrils but not to native insulin. Binding is characterized by a red-shifted AmB spectrum indicative of a more hydrophobic environment. Thus AmB seems to have a complementary face for amyloid fibrils but not the native protein. In addition, AmB interacts specifically with Congo Red, a known fibril-binding agent. In kinetic fibril formation studies, AmB was able to significantly kinetically delay the formation of Abeta 25-35 fibrils at pH 7.4 but not insulin fibrils at pH 2.
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Affiliation(s)
- Scott C Hartsel
- Department of Chemistry, University of Wisconsin-Eau Claire, 54702-4004, USA.
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24
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Weissmann C. Molecular genetics of transmissible spongiform encephalopathies: an introduction. J Toxicol Sci 2002; 27:69-77. [PMID: 12058449 DOI: 10.2131/jts.27.69] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Prnp knockout mice disrupted PrPC-related genes have played an essential role to elucidate the relationship between PrPC, a normal host gene product, and PrPSc, a protease-resistant, infectious PrP; Prnp knockout mice developed by Büeler et al. (1992) were completely protected against scrapie disease when challenged with mouse prions. Further, varying expression levels in PrPC were revisited along with a varying susceptibility of mouse prions, when mouse Prnp genes were introduced into Prnp% mice. How these murine models for human prion-related disease would contribute to the presently ongoing TSE research?
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Affiliation(s)
- Charles Weissmann
- MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, Queen Square, London WC1N 3BG, UK
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25
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Fraser JR. What is the basis of transmissible spongiform encephalopathy induced neurodegeneration and can it be repaired? Neuropathol Appl Neurobiol 2002; 28:1-11. [PMID: 11849558 DOI: 10.1046/j.1365-2990.2002.00376.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Once an animal becomes infected with a prion disease, or transmissible spongiform encephalopathy (TSE), the progression of infection is relentless and inevitably fatal, although often with such prolonged incubation periods that an alternative cause of death can intervene. Infection has been compared to 'setting a clock' which then runs inexorably as the disease spreads, usually through the lymphoreticular system and then via peripheral nerves to the central nervous system (CNS), although the mechanism controlling the protracted progression is not known. Clinical disease develops as characteristic degenerative changes in the CNS progress, but the molecular basis for this pathology is not clear, particularly the relationship between the deposition of abnormal PrP and neuronal dysfunction. Recent research has identified several means of slowing (if not stopping) the clock when infection has not yet reached the CNS; although the potential for later stage therapies seems limited, neuroprotective strategies which have been shown to be effective in other neurodegenerative conditions may also ameliorate TSE induced CNS pathology. This review focuses on our current knowledge of the key events following infection of the CNS and the opportunities for intervention once the CNS has become infected.
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Affiliation(s)
- J R Fraser
- Institute for Animal Health, Neuropathogenesis Unit, Ogston Building, Edinburgh, UK.
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26
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Enari M, Flechsig E, Weissmann C. Scrapie prion protein accumulation by scrapie-infected neuroblastoma cells abrogated by exposure to a prion protein antibody. Proc Natl Acad Sci U S A 2001; 98:9295-9. [PMID: 11470893 PMCID: PMC55414 DOI: 10.1073/pnas.151242598] [Citation(s) in RCA: 352] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Exposure of susceptible neuroblastoma N2a cells to mouse scrapie prions leads to infection, as evidenced by the continued presence of the scrapie form of the prion protein (PrP(Sc)) and infectivity after 300 or more cell doublings. We find that exposure to phosphatidylinositol-specific phospholipase C (PIPLC) or to the monoclonal anti-prion protein (PrP) antibody 6H4 not only prevents infection of susceptible N2a cells but also cures chronically scrapie-infected cultures, as judged by the long-term abrogation of PrP(Sc) accumulation after cessation of treatment. A nonpassaged, stationary infected culture rapidly loses PrP(Sc) when exposed to the antibody or PIPLC, indicating that the PrP(Sc) level is determined by steady state equilibrium between formation and degradation, and that depletion of the cellular form of PrP can interrupt the propagation of PrP(Sc). These findings encourage the belief that passive immunization may provide a therapeutic approach to prion disease.
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Affiliation(s)
- M Enari
- Medical Research Council Prion Unit, Neurogenetics, Imperial College School of Medicine at St. Mary's, London W2 1PG, United Kingdom
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