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Davidowitz EJ, Krishnamurthy PK, Lopez P, Jimenez H, Adrien L, Davies P, Moe JG. In Vivo Validation of a Small Molecule Inhibitor of Tau Self-Association in htau Mice. J Alzheimers Dis 2020; 73:147-161. [PMID: 31771053 PMCID: PMC6957711 DOI: 10.3233/jad-190465] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2019] [Indexed: 01/27/2023]
Abstract
Tau oligomers have been shown to transmit tau pathology from diseased neurons to healthy neurons through seeding, tau misfolding, and aggregation that is thought to play an influential role in the progression of Alzheimer's disease (AD) and related tauopathies. To develop a small molecule therapeutic for AD and related tauopathies, we have developed in vitro and cellular assays to select molecules inhibiting the first step in tau aggregation, the self-association of tau into oligomers. In vivo validation studies of an optimized lead compound were independently performed in the htau mouse model of tauopathy that expresses the human isoforms of tau without inherited tauopathy mutations that are irrelevant to AD. Treated mice did not show any adverse events related to the compound. The lead compound significantly reduced the level of self-associated tau and total and phosphorylated insoluble tau aggregates. The dose response was linear with respect to levels of compound in the brain. A confirmatory study was performed with male htau mice that gave consistent results. The results validated our screening approach by showing that targeting tau self-association can inhibit the entire tau aggregation pathway by using the selected and optimized lead compound whose activity translated from in vitro and cellular assays to an in vivo model of tau aggregation.
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Affiliation(s)
| | | | | | - Heidy Jimenez
- The Litwin-Zucker Research Center for the Study of Alzheimer’s Disease, The Feinstein Institute for Medical Research, Northwell Health, Manhasset, NY, USA
| | - Leslie Adrien
- The Litwin-Zucker Research Center for the Study of Alzheimer’s Disease, The Feinstein Institute for Medical Research, Northwell Health, Manhasset, NY, USA
| | - Peter Davies
- The Litwin-Zucker Research Center for the Study of Alzheimer’s Disease, The Feinstein Institute for Medical Research, Northwell Health, Manhasset, NY, USA
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Litberg TJ, Docter B, Hughes MP, Bourne J, Horowitz S. DNA Facilitates Oligomerization and Prevents Aggregation via DNA Networks. Biophys J 2019; 118:162-171. [PMID: 31839258 DOI: 10.1016/j.bpj.2019.11.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 10/11/2019] [Accepted: 11/05/2019] [Indexed: 12/12/2022] Open
Abstract
Previous studies have shown that nucleic acids can nucleate protein aggregation in disease-related proteins, but in other cases, they can act as molecular chaperones that prevent protein aggregation, even under extreme conditions. In this study, we describe the link between these two behaviors through a combination of electron microscopy and aggregation kinetics. We find that two different proteins become soluble under harsh conditions through oligomerization with DNA. These DNA/protein oligomers form "networks," which increase the speed of oligomerization. The cases of DNA both increasing and preventing protein aggregation are observed to stem from this enhanced oligomerization. This observation raises interesting questions about the role of nucleic acids in aggregate formation in disease states.
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Affiliation(s)
- Theodore J Litberg
- Department of Chemistry & Biochemistry, Knoebel Institute for Healthy Aging, University of Denver, Denver, Colorado
| | - Brianne Docter
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan
| | - Michael P Hughes
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, California; Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California; Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, California; Department of Energy, University of California, Los Angeles, Los Angeles, California; Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California
| | - Jennifer Bourne
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
| | - Scott Horowitz
- Department of Chemistry & Biochemistry, Knoebel Institute for Healthy Aging, University of Denver, Denver, Colorado.
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Wu D, Zhang W, Luo Q, Luo K, Huang L, Wang W, Huang T, Chen R, Lin Y, Pang D, Xiao G. Copper (II) promotes the formation of soluble neurotoxic PrP oligomers in acidic environment. J Cell Biochem 2010; 111:627-33. [DOI: 10.1002/jcb.22743] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Sasaki K, Minaki H, Iwaki T. Development of oligomeric prion-protein aggregates in a mouse model of prion disease. J Pathol 2009; 219:123-30. [DOI: 10.1002/path.2576] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Savvateeva-Popova E, Medvedeva A, Popov A, Evgen'ev M. Role of non-coding RNAs in neurodegeneration and stress response in Drosophila. Biotechnol J 2008; 3:1010-21. [PMID: 18702036 DOI: 10.1002/biot.200800120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The inherent limitations of genetic analysis in humans and other mammals as well as striking conservation of most genes controlling nervous system functioning in flies and mammals made Drosophila an attractive model to investigate various aspects of brain diseases. Since RNA research has made great progress in recent years here we present an overview of studies demonstrating the role of various non-coding RNAs in neurodegeneration and stress response in Drosophila as a model organism. We put special emphasis on the role of non-coding micro RNAs, hsr-omega transcripts, and artificial small highly structured RNAs as triggers of neuropathology including aggregates formation, cognitive abnormalities and other symptoms. Cellular stress is a conspicuous feature of many neurodegenerative diseases and the production of specialized proteins protects the nerve cells against aggregates formation. Therefore, herein we describe some data implicating various classes of non-coding RNAs in stress response in Drosophila. All these findings highlight Drosophila as an important model system to investigate various brain diseases potentially mediated by some non-coding RNAs including polyglutamine diseases, Alzheimer's disease, Huntigton's disease, and many others.
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Non-coding RNA as a trigger of neuropathologic disorder phenotypes in transgenic Drosophila. J Neural Transm (Vienna) 2008; 115:1629-42. [PMID: 18779919 DOI: 10.1007/s00702-008-0078-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 06/01/2008] [Indexed: 10/21/2022]
Abstract
At most, many protein-misfolding diseases develop as environmentally induced sporadic disorders. Recent studies indicate that the dynamic interplay between a wide repertoire of noncoding RNAs and the environment play an important role in brain development and pathogenesis of brain disorders. To elucidate this new issue, novel animal models which reproduce the most prominent disease manifestations are required. For this, transgenic Drosophila strains were constructed to express small highly structured, non-coding RNA under control of a heat shock promoter. Expression of the RNA induced formation of intracellular aggregates revealed by Thioflafin T in embryonic cell culture and Congo Red in the brain of transgenic flies. Also, this strongly perturbed the brain control of locomotion monitored by the parameters of sound production and memory retention of young 5-day-old males. This novel model demonstrates that expression of non-coding RNA alone is sufficient to trigger neuropathology.
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Geoghegan JC, Valdes PA, Orem NR, Deleault NR, Williamson RA, Harris BT, Supattapone S. Selective incorporation of polyanionic molecules into hamster prions. J Biol Chem 2007; 282:36341-53. [PMID: 17940287 DOI: 10.1074/jbc.m704447200] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The central pathogenic event of prion disease is the conformational conversion of a host protein, PrPC, into a pathogenic isoform, PrPSc. We previously showed that the protein misfolding cyclic amplification (PMCA) technique can be used to form infectious prion molecules de novo from purified native PrPC molecules in an autocatalytic process requiring accessory polyanions (Deleault, N. R., Harris, B. T., Rees, J. R., and Supattapone, S. (2007) Proc. Natl. Acad. Sci. U. S. A. 104, 9741-9746). Here we investigated the molecular mechanism by which polyanionic molecules facilitate infectious prion formation in vitro. Ina PMCA reaction lacking PrPSc template seed, synthetic polyA RNA molecules induce hamster HaPrPC to adopt a protease-sensitive, detergent-insoluble conformation reactive against antibodies specific for PrPSc. During PMCA, labeled nucleic acids form nuclease-resistant complexes with HaPrP molecules. Strikingly, purified HaPrPC molecules subjected to PMCA selectively incorporate an approximately 1-2.5-kb subset of [32P]polyA RNA molecules from a heterogeneous mixture ranging in size from approximately 0.1 to >6 kb. Neuropathological analysis of scrapie-infected hamsters using the fluorescent dye acridine orange revealed that RNA molecules co-localize with large extracellular HaPrP aggregates. These findings suggest that polyanionic molecules such as RNA may become selectively incorporated into stable complexes with PrP molecules during the formation of native hamster prions.
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Affiliation(s)
- James C Geoghegan
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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Savvateeva-Popova E, Popov A, Grossman A, Nikitina E, Medvedeva A, Peresleni A, Korochkin L, Moe JG, Davidowitz E, Pyatkov K, Myasnyankina E, Zatsepina O, Schostak N, Zelentsova E, Evgen'ev M. Pathogenic chaperone-like RNA induces congophilic aggregates and facilitates neurodegeneration in Drosophila. Cell Stress Chaperones 2007; 12:9-19. [PMID: 17441503 PMCID: PMC1874921 DOI: 10.1379/csc-222r.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Protein aggregation is a hallmark of many neurodegenerative diseases. RNA chaperones have been suggested to play a role in protein misfolding and aggregation. Noncoding, highly structured RNA recently has been demonstrated to facilitate transformation of recombinant and cellular prion protein into proteinase K-resistant, congophilic, insoluble aggregates and to generate cytotoxic oligomers in vitro. Transgenic Drosophila melanogaster strains were developed to express highly structured RNA under control of a heat shock promoter. Expression of a specific construct strongly perturbed fly behavior, caused significant decline in learning and memory retention of adult males, and was coincident with the formation of intracellular congophilic aggregates in the brain and other tissues of adult and larval stages. Additionally, neuronal cell pathology of adult flies was similar to that observed in human Parkinson's and Alzheimer's disease. This novel model demonstrates that expression of a specific highly structured RNA alone is sufficient to trigger neurodegeneration, possibly through chaperone-like facilitation of protein misfolding and aggregation.
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Adler V, Davidowitz E, Tamburi P, Rojas P, Grossman A. Alpha2-macroglobulin is a potential facilitator of prion protein transformation. Amyloid 2007; 14:1-10. [PMID: 17453620 DOI: 10.1080/13506120600960452] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Cellular prion protein changes conformation during transformation to an infectious scrapie isoform. One measure of transformation is the development of partial resistance to protease treatment. A fraction of human and bovine plasma was identified containing activity that facilitates transformation of cellular prion protein to a protease resistant isoform in the presence of RNA in the absence of seeded scrapie prion protein. Purification of proteins from this fraction led to the identification of alpha2-macroglobulin as an active component suggesting that it may facilitate conformational changes in prion protein in spontaneous forms of prion disease.
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Affiliation(s)
- Victor Adler
- Q-RNA, Inc., Audubon Business and Technology Center. 3960 Broadway, Suite 440C, New York, NY, 10032. USA
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