1
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Minikel EV, Zhao HT, Le J, O'Moore J, Pitstick R, Graffam S, Carlson GA, Kavanaugh MP, Kriz J, Kim JB, Ma J, Wille H, Aiken J, McKenzie D, Doh-Ura K, Beck M, O'Keefe R, Stathopoulos J, Caron T, Schreiber SL, Carroll JB, Kordasiewicz HB, Cabin DE, Vallabh SM. Prion protein lowering is a disease-modifying therapy across prion disease stages, strains and endpoints. Nucleic Acids Res 2020; 48:10615-10631. [PMID: 32776089 PMCID: PMC7641729 DOI: 10.1093/nar/gkaa616] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/23/2020] [Accepted: 07/13/2020] [Indexed: 12/11/2022] Open
Abstract
Lowering of prion protein (PrP) expression in the brain is a genetically validated therapeutic hypothesis in prion disease. We recently showed that antisense oligonucleotide (ASO)-mediated PrP suppression extends survival and delays disease onset in intracerebrally prion-infected mice in both prophylactic and delayed dosing paradigms. Here, we examine the efficacy of this therapeutic approach across diverse paradigms, varying the dose and dosing regimen, prion strain, treatment timepoint, and examining symptomatic, survival, and biomarker readouts. We recapitulate our previous findings with additional PrP-targeting ASOs, and demonstrate therapeutic benefit against four additional prion strains. We demonstrate that <25% PrP suppression is sufficient to extend survival and delay symptoms in a prophylactic paradigm. Rise in both neuroinflammation and neuronal injury markers can be reversed by a single dose of PrP-lowering ASO administered after the detection of pathological change. Chronic ASO-mediated suppression of PrP beginning at any time up to early signs of neuropathology confers benefit similar to constitutive heterozygous PrP knockout. Remarkably, even after emergence of frank symptoms including weight loss, a single treatment prolongs survival by months in a subset of animals. These results support ASO-mediated PrP lowering, and PrP-lowering therapeutics in general, as a promising path forward against prion disease.
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Affiliation(s)
- Eric Vallabh Minikel
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Prion Alliance, Cambridge, MA, 02139, USA
- Henry and Allison McCance Center for Brain Health, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Hien T Zhao
- Ionis Pharmaceuticals Inc, Carlsbad, CA 92010, USA
| | - Jason Le
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jill O'Moore
- McLaughlin Research Institute, Great Falls, MT 59405, USA
| | - Rose Pitstick
- McLaughlin Research Institute, Great Falls, MT 59405, USA
| | | | | | | | - Jasna Kriz
- Cervo Brain Research Center, Université Laval, Québec, QC G1J 2G3, Canada
| | | | - Jiyan Ma
- Center for Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Holger Wille
- University of Alberta, Edmonton, AB T6G 2M8, Canada
| | - Judd Aiken
- University of Alberta, Edmonton, AB T6G 2M8, Canada
| | | | - Katsumi Doh-Ura
- Department of Neurochemistry, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan
| | - Matthew Beck
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Rhonda O'Keefe
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Tyler Caron
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Stuart L Schreiber
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Department of Chemistry & Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | | | | | | | - Sonia M Vallabh
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Prion Alliance, Cambridge, MA, 02139, USA
- Henry and Allison McCance Center for Brain Health, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
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2
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Corbett GT, Wang Z, Hong W, Colom-Cadena M, Rose J, Liao M, Asfaw A, Hall TC, Ding L, DeSousa A, Frosch MP, Collinge J, Harris DA, Perkinton MS, Spires-Jones TL, Young-Pearse TL, Billinton A, Walsh DM. PrP is a central player in toxicity mediated by soluble aggregates of neurodegeneration-causing proteins. Acta Neuropathol 2020; 139:503-526. [PMID: 31853635 PMCID: PMC7035229 DOI: 10.1007/s00401-019-02114-9] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/10/2019] [Accepted: 12/10/2019] [Indexed: 12/30/2022]
Abstract
Neurodegenerative diseases are an enormous public health problem, affecting tens of millions of people worldwide. Nearly all of these diseases are characterized by oligomerization and fibrillization of neuronal proteins, and there is great interest in therapeutic targeting of these aggregates. Here, we show that soluble aggregates of α-synuclein and tau bind to plate-immobilized PrP in vitro and on mouse cortical neurons, and that this binding requires at least one of the same N-terminal sites at which soluble Aβ aggregates bind. Moreover, soluble aggregates of tau, α-synuclein and Aβ cause both functional (impairment of LTP) and structural (neuritic dystrophy) compromise and these deficits are absent when PrP is ablated, knocked-down, or when neurons are pre-treated with anti-PrP blocking antibodies. Using an all-human experimental paradigm involving: (1) isogenic iPSC-derived neurons expressing or lacking PRNP, and (2) aqueous extracts from brains of individuals who died with Alzheimer's disease, dementia with Lewy bodies, and Pick's disease, we demonstrate that Aβ, α-synuclein and tau are toxic to neurons in a manner that requires PrPC. These results indicate that PrP is likely to play an important role in a variety of late-life neurodegenerative diseases and that therapeutic targeting of PrP, rather than individual disease proteins, may have more benefit for conditions which involve the aggregation of more than one protein.
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Affiliation(s)
- Grant T Corbett
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Zemin Wang
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Wei Hong
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Marti Colom-Cadena
- Centre for Discovery Brain Sciences and UK Dementia Research Institute, University of Edinburgh, Edinburgh, EH89JZ, UK
| | - Jamie Rose
- Centre for Discovery Brain Sciences and UK Dementia Research Institute, University of Edinburgh, Edinburgh, EH89JZ, UK
| | - Meichen Liao
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Adhana Asfaw
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Tia C Hall
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Lai Ding
- Program for Interdisciplinary Neuroscience, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - Alexandra DeSousa
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Matthew P Frosch
- Massachusetts General Institute for Neurodegenerative Disease, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA
| | - John Collinge
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, UK
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, USA
| | | | - Tara L Spires-Jones
- Centre for Discovery Brain Sciences and UK Dementia Research Institute, University of Edinburgh, Edinburgh, EH89JZ, UK
| | - Tracy L Young-Pearse
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Andrew Billinton
- Neuroscience, IMED Biotechnology Unit, AstraZeneca, Cambridge, CB21 6GH, UK
| | - Dominic M Walsh
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA.
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3
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Reidenbach AG, Minikel EV, Zhao HT, Guzman SG, Leed AJ, Mesleh MF, Kordasiewicz HB, Schreiber SL, Vallabh SM. Characterization of the Prion Protein Binding Properties of Antisense Oligonucleotides. Biomolecules 2019; 10:E1. [PMID: 31861275 PMCID: PMC7022474 DOI: 10.3390/biom10010001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 12/12/2019] [Accepted: 12/13/2019] [Indexed: 01/08/2023] Open
Abstract
Antisense oligonucleotides (ASOs) designed to lower prion protein (PrP) expression in the brain through RNase H1-mediated degradation of PrP RNA are in development as prion disease therapeutics. ASOs were previously reported to sequence-independently interact with PrP and inhibit prion accumulation in cell culture, yet in vivo studies using a new generation of ASOs found that only PrP-lowering sequences were effective at extending survival. Cerebrospinal fluid (CSF) PrP has been proposed as a pharmacodynamic biomarker for trials of such ASOs, but is only interpretable if PrP lowering is indeed the relevant mechanism of action in vivo and if measurement of PrP is unconfounded by any PrP-ASO interaction. Here, we examine the PrP-binding and antiprion properties of ASOs in vitro and in cell culture. Binding parameters determined by isothermal titration calorimetry were similar across all ASOs tested, indicating that ASOs of various chemistries bind full-length recombinant PrP with low- to mid-nanomolar affinity in a sequence-independent manner. Nuclear magnetic resonance, dynamic light scattering, and visual inspection of ASO-PrP mixtures suggested, however, that this interaction is characterized by the formation of large aggregates, a conclusion further supported by the salt dependence of the affinity measured by isothermal titration calorimetry. Sequence-independent inhibition of prion accumulation in cell culture was observed. The inefficacy of non-PrP-lowering ASOs against prion disease in vivo may be because their apparent activity in vitro is an artifact of aggregation, or because the concentration of ASOs in relevant compartments within the central nervous system (CNS) quickly drops below the effective concentration for sequence-independent antiprion activity after bolus dosing into CSF. Measurements of PrP concentration in human CSF were not impacted by the addition of ASO. These findings support the further development of PrP-lowering ASOs and of CSF PrP as a pharmacodynamic biomarker.
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Affiliation(s)
- Andrew G. Reidenbach
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; (A.G.R.); (E.V.M.); (S.G.G.); (S.L.S.)
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Eric Vallabh Minikel
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; (A.G.R.); (E.V.M.); (S.G.G.); (S.L.S.)
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Prion Alliance, Cambridge, MA 02139, USA
| | - Hien T. Zhao
- Ionis Pharmaceuticals, Carlsbad, CA 92010, USA; (H.T.Z.); (H.B.K.)
| | - Stacy G. Guzman
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; (A.G.R.); (E.V.M.); (S.G.G.); (S.L.S.)
- Exceptional Research Opportunities Program (EXROP), Howard Hughes Medical Institute (HHMI), Chevy Chase, MD 20815, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alison J. Leed
- Center for the Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; (A.J.L.); (M.F.M.)
| | - Michael F. Mesleh
- Center for the Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; (A.J.L.); (M.F.M.)
| | | | - Stuart L. Schreiber
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; (A.G.R.); (E.V.M.); (S.G.G.); (S.L.S.)
- Department of Chemistry & Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Sonia M. Vallabh
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; (A.G.R.); (E.V.M.); (S.G.G.); (S.L.S.)
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Prion Alliance, Cambridge, MA 02139, USA
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4
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Raymond GJ, Zhao HT, Race B, Raymond LD, Williams K, Swayze EE, Graffam S, Le J, Caron T, Stathopoulos J, O'Keefe R, Lubke LL, Reidenbach AG, Kraus A, Schreiber SL, Mazur C, Cabin DE, Carroll JB, Minikel EV, Kordasiewicz H, Caughey B, Vallabh SM. Antisense oligonucleotides extend survival of prion-infected mice. JCI Insight 2019; 5:131175. [PMID: 31361599 PMCID: PMC6777807 DOI: 10.1172/jci.insight.131175] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Prion disease is a fatal, incurable neurodegenerative disease of humans and other mammals caused by conversion of cellular prion protein (PrPC) into a self-propagating neurotoxic conformer (prions; PrPSc). Strong genetic proofs of concept support lowering PrP expression as a therapeutic strategy. Antisense oligonucleotides (ASOs) can provide a practical route to lowering 1 target mRNA in the brain, but their development for prion disease has been hindered by 3 unresolved issues from prior work: uncertainty about mechanism of action, unclear potential for efficacy against established prion infection, and poor tolerability of drug delivery by osmotic pumps. Here, we test ASOs delivered by bolus intracerebroventricular injection to intracerebrally prion-infected WT mice. Prophylactic treatments given every 2–3 months extended survival times 61%–98%, and a single injection at 120 days after infection, near the onset of clinical signs, extended survival 55% (87 days). In contrast, a nontargeting control ASO was ineffective. Thus, PrP lowering is the mechanism of action of ASOs effective against prion disease in vivo, and infrequent — or even single — bolus injections of ASOs can slow prion neuropathogenesis and markedly extend survival, even when initiated near clinical signs. These findings should empower development of PrP-lowering therapy for prion disease. ASO-mediated prion protein suppression delays disease and extends survival, even in mice with established prion infection.
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Affiliation(s)
- Gregory J Raymond
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, Montana, USA
| | | | - Brent Race
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, Montana, USA
| | - Lynne D Raymond
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, Montana, USA
| | - Katie Williams
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, Montana, USA
| | - Eric E Swayze
- Ionis Pharmaceuticals Inc., Carlsbad, California, USA
| | - Samantha Graffam
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Jason Le
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Tyler Caron
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | | | - Rhonda O'Keefe
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Lori L Lubke
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, Montana, USA
| | | | - Allison Kraus
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, Montana, USA
| | | | - Curt Mazur
- Ionis Pharmaceuticals Inc., Carlsbad, California, USA
| | | | | | - Eric Vallabh Minikel
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, Montana, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.,Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, Massachusetts, USA.,Prion Alliance, Cambridge, Massachusetts, USA
| | | | - Byron Caughey
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, Montana, USA
| | - Sonia M Vallabh
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, Montana, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.,Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, Massachusetts, USA.,Prion Alliance, Cambridge, Massachusetts, USA
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5
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Yeldell SB, Ruble BK, Dmochowski IJ. Oligonucleotide modifications enhance probe stability for single cell transcriptome in vivo analysis (TIVA). Org Biomol Chem 2017; 15:10001-10009. [PMID: 29052679 PMCID: PMC5718921 DOI: 10.1039/c7ob02353g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Single cell transcriptomics provides a powerful discovery tool for identifying new cell types and functions as well as a means to probe molecular features of the etiology and treatment of human diseases, including cancer. However, such analyses are limited by the difficulty of isolating mRNA from single cells within biological samples. We recently introduced a photochemical method for isolating mRNA from single living cells, Transcriptome In Vivo Analysis (TIVA). The TIVA probe is a "caged" polyU : polyA oligonucleotide hairpin designed to enter live tissue, where site-specific activation with 405 nm laser reveals the polyU-biotin strand to bind mRNA in a target cell, enabling subsequent mRNA isolation and sequencing. The TIVA method is well suited for analysis of living cells in resected tissue, but has not yet been applied to living cells in whole organisms. Adapting TIVA to this more challenging environment requires a probe with higher thermal stability, more robust caging, and greater nuclease resistance. In this paper we present modifications to the original TIVA probe with multiple aspects of enhanced stability. These newer probes utilize an extended 22mer polyU capture strand with two 9mer polyA blocking strands ("22/9/9") for higher thermal stability pre-photolysis and improved mRNA capture affinity post-photolysis. The "22/9/9 GC" probe features a terminal GC pair to reduce pre-photolysis interactions with mRNA by more than half. The "PS-22/9/9" probe features a phosphorothioated backbone, which extends serum stability from <1 h to at least 48 h, and also mediates uptake into cultured human fibroblasts.
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Affiliation(s)
- S B Yeldell
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104-6323, USA.
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6
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Volk DE, Lokesh GLR. Development of Phosphorothioate DNA and DNA Thioaptamers. Biomedicines 2017; 5:E41. [PMID: 28703779 PMCID: PMC5618299 DOI: 10.3390/biomedicines5030041] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/03/2017] [Accepted: 07/11/2017] [Indexed: 02/07/2023] Open
Abstract
Nucleic acid aptamers are short RNA- or DNA-based affinity reagents typically selected from combinatorial libraries to bind to a specific target such as a protein, a small molecule, whole cells or even animals. Aptamers have utility in the development of diagnostic, imaging and therapeutic applications due to their size, physico-chemical nature and ease of synthesis and modification to suit the application. A variety of oligonucleotide modifications have been used to enhance the stability of aptamers from nuclease degradation in vivo. The non-bridging oxygen atoms of the phosphodiester backbones of RNA and DNA aptamers can be substituted with one or two sulfur atoms, resulting in thioaptamers with phosphorothioate or phosphorodithioate linkages, respectively. Such thioaptamers are known to have increased binding affinity towards their target, as well as enhanced resistance to nuclease degradation. In this review, we discuss the development of phosphorothioate chemistry and thioaptamers, with a brief review of selection methods.
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Affiliation(s)
- David E Volk
- McGovern Medical School, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, TX 77030, USA.
| | - Ganesh L R Lokesh
- McGovern Medical School, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, TX 77030, USA.
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7
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Unraveling Prion Protein Interactions with Aptamers and Other PrP-Binding Nucleic Acids. Int J Mol Sci 2017; 18:ijms18051023. [PMID: 28513534 PMCID: PMC5454936 DOI: 10.3390/ijms18051023] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/23/2017] [Accepted: 05/04/2017] [Indexed: 12/13/2022] Open
Abstract
Transmissible spongiform encephalopathies (TSEs) are a group of neurodegenerative disorders that affect humans and other mammals. The etiologic agents common to these diseases are misfolded conformations of the prion protein (PrP). The molecular mechanisms that trigger the structural conversion of the normal cellular PrP (PrPC) into the pathogenic conformer (PrPSc) are still poorly understood. It is proposed that a molecular cofactor would act as a catalyst, lowering the activation energy of the conversion process, therefore favoring the transition of PrPC to PrPSc. Several in vitro studies have described physical interactions between PrP and different classes of molecules, which might play a role in either PrP physiology or pathology. Among these molecules, nucleic acids (NAs) are highlighted as potential PrP molecular partners. In this context, the SELEX (Systematic Evolution of Ligands by Exponential Enrichment) methodology has proven extremely valuable to investigate PrP–NA interactions, due to its ability to select small nucleic acids, also termed aptamers, that bind PrP with high affinity and specificity. Aptamers are single-stranded DNA or RNA oligonucleotides that can be folded into a wide range of structures (from harpins to G-quadruplexes). They are selected from a nucleic acid pool containing a large number (1014–1016) of random sequences of the same size (~20–100 bases). Aptamers stand out because of their potential ability to bind with different affinities to distinct conformations of the same protein target. Therefore, the identification of high-affinity and selective PrP ligands may aid the development of new therapies and diagnostic tools for TSEs. This review will focus on the selection of aptamers targeted against either full-length or truncated forms of PrP, discussing the implications that result from interactions of PrP with NAs, and their potential advances in the studies of prions. We will also provide a critical evaluation, assuming the advantages and drawbacks of the SELEX (Systematic Evolution of Ligands by Exponential Enrichment) technique in the general field of amyloidogenic proteins.
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8
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Giles K, Olson SH, Prusiner SB. Developing Therapeutics for PrP Prion Diseases. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a023747. [PMID: 28096242 DOI: 10.1101/cshperspect.a023747] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The prototypical PrP prion diseases are invariably fatal, and the search for agents to treat them spans more than 30 years, with limited success. However, in the last few years, the application of high-throughput screening, medicinal chemistry, and pharmacokinetic optimization has led to important advances. The PrP prion inoculation paradigm provides a robust assay for testing therapeutic efficacy, and a dozen compounds have been reported that lead to meaningful extension in survival of prion-infected mice. Here, we review the history and recent progress in the field, focusing on studies validated in animal models. Based on screens in cells infected with mouse-passaged PrP prions, orally available compounds were generated that double or even triple the survival of mice infected with the same prion strain. Unfortunately, no compounds have yet shown efficacy against human prions. Nevertheless, the speed of the recent advances brings hope that an effective therapeutic can be developed. A successful treatment for any neurodegenerative disease would be a major achievement, and the growing understanding that the more common neurodegenerative diseases, including Alzheimer's and Parkinson's, progress by an analogous prion mechanism serves to highlight the importance of antiprion therapeutics.
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Affiliation(s)
- Kurt Giles
- Institute for Neurodegenerative Diseases, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94143.,Department of Neurology, University of California, San Francisco, San Francisco, California 94143
| | - Steven H Olson
- Institute for Neurodegenerative Diseases, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94143.,Department of Neurology, University of California, San Francisco, San Francisco, California 94143
| | - Stanley B Prusiner
- Institute for Neurodegenerative Diseases, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94143.,Department of Neurology, University of California, San Francisco, San Francisco, California 94143.,Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California 94143
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9
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Abstract
Transmissible encephalopathies (TSEs) are believed by many to arise by spontaneous conversion of host prion protein (PrP) into an infectious amyloid (PrP-res, PrP (Sc) ) without nucleic acid. Many TSE agents reside in the environment, with infection controlled by public health measures. These include the disappearance of kuru with the cessation of ritual cannibalism, the dramatic reduction of epidemic bovine encephalopathy (BSE) by removal of contaminated feed, and the lack of endemic scrapie in geographically isolated Australian sheep with susceptible PrP genotypes. While prion protein modeling has engendered an intense focus on common types of protein misfolding and amyloid formation in diverse organisms and diseases, the biological characteristics of infectious TSE agents, and their recognition by the host as foreign entities, raises several fundamental new directions for fruitful investigation such as: (1) unrecognized microbial agents in the environmental metagenome that may cause latent neurodegenerative disease, (2) the evolutionary social and protective functions of different amyloid proteins in diverse organisms from bacteria to mammals, and (3) amyloid formation as a beneficial innate immune response to stress (infectious and non-infectious). This innate process however, once initiated, can become unstoppable in accelerated neuronal aging.
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10
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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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Nazor Friberg K, Hung G, Wancewicz E, Giles K, Black C, Freier S, Bennett F, Dearmond SJ, Freyman Y, Lessard P, Ghaemmaghami S, Prusiner SB. Intracerebral Infusion of Antisense Oligonucleotides Into Prion-infected Mice. MOLECULAR THERAPY. NUCLEIC ACIDS 2012; 1:e9. [PMID: 23344724 PMCID: PMC3381600 DOI: 10.1038/mtna.2011.6] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Mice deficient for the cellular prion protein (PrPC) do not develop prion disease; accordingly, gene-based strategies to diminish PrPC expression are of interest. We synthesized a series of chemically modified antisense oligonucleotides (ASOs) targeted against mouse Prnp messenger RNA (mRNA) and identified those that were most effective in decreasing PrPC expression. Those ASOs were also evaluated in scrapie-infected cultured cells (ScN2a) for their efficacy in diminishing the levels of the disease-causing prion protein (PrPSc). When the optimal ASO was infused intracerebrally into FVB mice over a 14-day period beginning 1 day after infection with the Rocky Mountain Laboratory (RML) strain of mouse prions, a prolongation of the incubation period of almost 2 months was observed. Whether ASOs can be used to develop an effective therapy for patients dying of Creutzfeldt–Jakob disease remains to be established.
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Affiliation(s)
- Karah Nazor Friberg
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, California, USA
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Karpuj MV, Gelibter-Niv S, Tiran A, Rambold A, Tatzelt J, Nunziante M, Schatzl HM. Conditional modulation of membrane protein expression in cultured cells mediated by prion protein recognition of short phosphorothioate oligodeoxynucleotides. J Biol Chem 2010; 286:6911-7. [PMID: 21156803 DOI: 10.1074/jbc.m110.194662] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We demonstrate that the levels of native as well as transfected prion protein (PrP) are lowered in various cell lines exposed to phosphorothioate oligodeoxynucleotides (PS-DNA) and can be rapidly reverted to their normal amounts by removal of PS-DNA. This transient modulation was independent of the glycosylation state of PrP, and in addition, all three PrP glycoforms were susceptible to PS-DNA treatment. Deletion of the N-terminal domain (amino acids 23-99), but not of the other domains of PrP, abrogated its PS-DNA-mediated down-regulation. PrP versions localized in the mitochondria, cytoplasm, or nucleus were not modulated by PS-DNA, indicating that PrP surface exposure is required for executing this effect. Proteins that in their native forms were not responsive to PS-DNA, such as thymocyte antigen 1 (Thy1), Doppel protein (Dpl), green fluorescent protein (GFP), and cyan fluorescent protein (CFP), became susceptible to PS-DNA-mediated down-regulation following introduction of the N terminus of PrP into their sequence. These observations demonstrate the essential role of the N-terminal domain for promoting oligonucleotide-mediated reduction of the PrP level and suggest that transient treatment of cultured cells with PS-DNA may provide a general method for targeted modulation of the levels of desired surface proteins in a conditional and reversible manner.
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Affiliation(s)
- Marcela Viviana Karpuj
- Institute of Biochemistry, Food Science and Nutrition Food and Environmental Quality Sciences, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel.
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Yin S, Fan X, Yu S, Li C, Sy MS. Binding of recombinant but not endogenous prion protein to DNA causes DNA internalization and expression in mammalian cells. J Biol Chem 2008; 283:25446-25454. [PMID: 18622017 DOI: 10.1074/jbc.m800814200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recombinant prion protein, rPrP, binds DNA. Both the KKRPK motif and the octapeptide repeat region of rPrP are essential for maximal binding. rPrP with pathogenic insertional mutations binds more DNA than wild-type rPrP. DNA promotes the aggregation of rPrP and protects its N terminus from proteinase K digestion. When rPrP is mixed with an expression plasmid and Ca(2+), the rPrP.DNA complex is taken up by mammalian cells leading to gene expression. In the presence of Ca(2+), rPrP by itself is also taken up by cells in a temperature- and pinocytosis-dependent manner. Cells do not take up rPrP(DeltaKKRPK), which lacks the KKRPK motif. Thus, rPrP is the carrier for DNA and the KKRPK motif is essential for its uptake. When mixed with DNA, a pentapeptide KKRPK, but not KKKKK, is sufficient for DNA internalization and expression. In contrast, whereas the normal cellular prion protein, PrP(C), on the cell surface can also internalize DNA, the imported DNA is not expressed. These findings may have relevance to the normal functions of PrP(C) and the pathogenic mechanisms of human prion disease.
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Affiliation(s)
- Shaoman Yin
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44120
| | - Xingjun Fan
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44120
| | - Shuiliang Yu
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44120
| | - Chaoyang Li
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44120
| | - Man-Sun Sy
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44120.
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