151
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Sarto-Jackson I, Tomaska L. How to bake a brain: yeast as a model neuron. Curr Genet 2016; 62:347-70. [PMID: 26782173 DOI: 10.1007/s00294-015-0554-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 12/09/2015] [Accepted: 12/10/2015] [Indexed: 12/14/2022]
Abstract
More than 30 years ago Dan Koshland published an inspirational essay presenting the bacterium as a model neuron (Koshland, Trends Neurosci 6:133-137, 1983). In the article he argued that there are several similarities between neurons and bacterial cells in "how signals are processed within a cell or how this processing machinery can be modified to produce plasticity". He then explored the bacterial chemosensory system to emphasize its attributes that are analogous to information processing in neurons. In this review, we wish to expand Koshland's original idea by adding the yeast cell to the list of useful models of a neuron. The fact that yeasts and neurons are specialized versions of the eukaryotic cell sharing all principal components sets the stage for a grand evolutionary tinkering where these components are employed in qualitatively different tasks, but following analogous molecular logic. By way of example, we argue that evolutionarily conserved key components involved in polarization processes (from budding or mating in Saccharomyces cervisiae to neurite outgrowth or spinogenesis in neurons) are shared between yeast and neurons. This orthologous conservation of modules makes S. cervisiae an excellent model organism to investigate neurobiological questions. We substantiate this claim by providing examples of yeast models used for studying neurological diseases.
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Affiliation(s)
- Isabella Sarto-Jackson
- Konrad Lorenz Institute for Evolution and Cognition Research, Martinstraße 12, 3400, Klosterneuburg, Austria.
| | - Lubomir Tomaska
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina B-1, Ilkovicova 6, 842 15, Bratislava, Slovak Republic.
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152
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Torrente MP, Chuang E, Noll MM, Jackrel ME, Go MS, Shorter J. Mechanistic Insights into Hsp104 Potentiation. J Biol Chem 2016; 291:5101-15. [PMID: 26747608 DOI: 10.1074/jbc.m115.707976] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Indexed: 12/25/2022] Open
Abstract
Potentiated variants of Hsp104, a protein disaggregase from yeast, can dissolve protein aggregates connected to neurodegenerative diseases such as Parkinson disease and amyotrophic lateral sclerosis. However, the mechanisms underlying Hsp104 potentiation remain incompletely defined. Here, we establish that 2-3 subunits of the Hsp104 hexamer must bear an A503V potentiating mutation to elicit enhanced disaggregase activity in the absence of Hsp70. We also define the ATPase and substrate-binding modalities needed for potentiated Hsp104(A503V) activity in vitro and in vivo. Hsp104(A503V) disaggregase activity is strongly inhibited by the Y257A mutation that disrupts substrate binding to the nucleotide-binding domain 1 (NBD1) pore loop and is abolished by the Y662A mutation that disrupts substrate binding to the NBD2 pore loop. Intriguingly, Hsp104(A503V) disaggregase activity responds to mixtures of ATP and adenosine 5'-(γ-thio)-triphosphate (a slowly hydrolyzable ATP analogue) differently from Hsp104. Indeed, an altered pattern of ATP hydrolysis and altered allosteric signaling between NBD1 and NBD2 are likely critical for potentiation. Hsp104(A503V) variants bearing inactivating Walker A or Walker B mutations in both NBDs are inoperative. Unexpectedly, however, Hsp104(A503V) retains potentiated activity upon introduction of sensor-1 mutations that reduce ATP hydrolysis at NBD1 (T317A) or NBD2 (N728A). Hsp104(T317A/A503V) and Hsp104(A503V/N728A) rescue TDP-43 (TAR DNA-binding protein 43), FUS (fused in sarcoma), and α-synuclein toxicity in yeast. Thus, Hsp104(A503V) displays a more robust activity that is unperturbed by sensor-1 mutations that greatly reduce Hsp104 activity in vivo. Indeed, ATPase activity at NBD1 or NBD2 is sufficient for Hsp104 potentiation. Our findings will empower design of ameliorated therapeutic disaggregases for various neurodegenerative diseases.
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Affiliation(s)
| | - Edward Chuang
- From the Department of Biochemistry and Biophysics and the Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Megan M Noll
- From the Department of Biochemistry and Biophysics and
| | | | - Michelle S Go
- From the Department of Biochemistry and Biophysics and
| | - James Shorter
- From the Department of Biochemistry and Biophysics and the Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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153
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Tsubota A, Ichijo H, Homma K. Mislocalization, aggregation formation and defect in proteolysis in ALS. AIMS MOLECULAR SCIENCE 2016. [DOI: 10.3934/molsci.2016.2.246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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154
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Fan AC, Leung AKL. RNA Granules and Diseases: A Case Study of Stress Granules in ALS and FTLD. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 907:263-96. [PMID: 27256390 DOI: 10.1007/978-3-319-29073-7_11] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
RNA granules are microscopically visible cellular structures that aggregate by protein-protein and protein-RNA interactions. Using stress granules as an example, we discuss the principles of RNA granule formation, which rely on the multivalency of RNA and multi-domain proteins as well as low-affinity interactions between proteins with prion-like/low-complexity domains (e.g. FUS and TDP-43). We then explore how dysregulation of RNA granule formation is linked to neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), and discuss possible strategies for therapeutic intervention.
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Affiliation(s)
- Alexander C Fan
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Anthony K L Leung
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
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155
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Jackrel ME, Yee K, Tariq A, Chen AI, Shorter J. Disparate Mutations Confer Therapeutic Gain of Hsp104 Function. ACS Chem Biol 2015; 10:2672-9. [PMID: 26441009 DOI: 10.1021/acschembio.5b00765] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hsp104, a protein disaggregase from yeast, can be engineered and potentiated to counter TDP-43, FUS, or α-synuclein misfolding and toxicity implicated in neurodegenerative disease. Here, we reveal that extraordinarily disparate mutations potentiate Hsp104. Remarkably, diverse single missense mutations at 20 different positions interspersed throughout the middle domain (MD) and small domain of nucleotide-binding domain 1 (NBD1) confer a therapeutic gain of Hsp104 function. Moreover, potentiation emerges from deletion of MD helix 3 or 4 or via synergistic missense mutations in the MD distal loop and helix 4. We define the most critical aspect of Hsp104 potentiation as enhanced disaggregase activity in the absence of Hsp70 and Hsp40. We suggest that potentiation likely stems from a loss of a fragilely constrained autoinhibited state that enables precise spatiotemporal regulation of disaggregase activity.
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Affiliation(s)
- Meredith E. Jackrel
- Department of Biochemistry and Biophysics, ‡Cell and Molecular Biology Graduate
Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Keolamau Yee
- Department of Biochemistry and Biophysics, ‡Cell and Molecular Biology Graduate
Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Amber Tariq
- Department of Biochemistry and Biophysics, ‡Cell and Molecular Biology Graduate
Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Annie I. Chen
- Department of Biochemistry and Biophysics, ‡Cell and Molecular Biology Graduate
Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - James Shorter
- Department of Biochemistry and Biophysics, ‡Cell and Molecular Biology Graduate
Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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156
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Shrestha A, Megeney LA. Yeast proteinopathy models: a robust tool for deciphering the basis of neurodegeneration. MICROBIAL CELL 2015; 2:458-465. [PMID: 28357271 PMCID: PMC5354604 DOI: 10.15698/mic2015.12.243] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein quality control or proteostasis is an essential determinant of basic cell health and aging. Eukaryotic cells have evolved a number of proteostatic mechanisms to ensure that proteins retain functional conformation, or are rapidly degraded when proteins misfold or self-aggregate. Disruption of proteostasis is now widely recognized as a key feature of aging related illness, specifically neurodegenerative disease. For example, Alzheimer’s disease, Huntington’s disease, Parkinson’s disease and Amyotrophic Lateral Sclerosis (ALS) each target and afflict distinct neuronal cell subtypes, yet this diverse array of human pathologies share the defining feature of aberrant protein aggregation within the affected cell population. Here, we review the use of budding yeast as a robust proxy to study the intersection between proteostasis and neurodegenerative disease. The humanized yeast model has proven to be an amenable platform to identify both, conserved proteostatic mechanisms across eukaryotic phyla and novel disease specific molecular dysfunction. Moreover, we discuss the intriguing concept that yeast specific proteins may be utilized as bona fide therapeutic agents, to correct proteostasis errors across various forms of neurodegeneration.
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Affiliation(s)
- Amit Shrestha
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Sprott Centre for Stem Cell Research, The Ottawa Hospital, Ottawa, Ontario, Canada. ; Department of Cellular and Molecular Medicine University of Ottawa, Ottawa, Ontario, Canada
| | - Lynn A Megeney
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Sprott Centre for Stem Cell Research, The Ottawa Hospital, Ottawa, Ontario, Canada. ; Department of Cellular and Molecular Medicine University of Ottawa, Ottawa, Ontario, Canada ; Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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157
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Aditi, Glass L, Dawson TR, Wente SR. An amyotrophic lateral sclerosis-linked mutation in GLE1 alters the cellular pool of human Gle1 functional isoforms. Adv Biol Regul 2015; 62:25-36. [PMID: 26776475 DOI: 10.1016/j.jbior.2015.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/04/2015] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a lethal late onset motor neuron disease with underlying cellular defects in RNA metabolism. In prior studies, two deleterious heterozygous mutations in the gene encoding human (h)Gle1 were identified in ALS patients. hGle1 is an mRNA processing modulator that requires inositol hexakisphosphate (IP6) binding for function. Interestingly, one hGLE1 mutation (c.1965-2A>C) results in a novel 88 amino acid C-terminal insertion, generating an altered protein. Like hGle1A, at steady state, the altered protein termed hGle1-IVS14-2A>C is absent from the nuclear envelope rim and localizes to the cytoplasm. hGle1A performs essential cytoplasmic functions in translation and stress granule regulation. Therefore, we speculated that the ALS disease pathology results from altered cellular pools of hGle1 and increased cytoplasmic hGle1 activity. GFP-hGle1-IVS14-2A>C localized to stress granules comparably to GFP-hGle1A, and rescued stress granule defects following siRNA-mediated hGle1 depletion. As described for hGle1A, overexpression of the hGle1-IVS14-2A>C protein also induced formation of larger SGs. Interestingly, hGle1A and the disease associated hGle1-IVS14-2A>C overexpression induced the formation of distinct cytoplasmic protein aggregates that appear similar to those found in neurodegenerative diseases. Strikingly, the ALS-linked hGle1-IVS14-2A>C protein also rescued mRNA export defects upon depletion of endogenous hGle1, acting in a potentially novel bi-functional manner. We conclude that the ALS-linked hGle1-c.1965-2A>C mutation generates a protein isoform capable of both hGle1A- and hGle1B-ascribed functions, and thereby uncoupled from normal mechanisms of hGle1 regulation.
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Affiliation(s)
- Aditi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA
| | - Laura Glass
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA
| | - T Renee Dawson
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA
| | - Susan R Wente
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.
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158
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Vermulst M, Denney AS, Lang MJ, Hung CW, Moore S, Moseley MA, Mosely AM, Thompson JW, Thompson WJ, Madden V, Gauer J, Wolfe KJ, Summers DW, Schleit J, Sutphin GL, Haroon S, Holczbauer A, Caine J, Jorgenson J, Cyr D, Kaeberlein M, Strathern JN, Duncan MC, Erie DA. Transcription errors induce proteotoxic stress and shorten cellular lifespan. Nat Commun 2015; 6:8065. [PMID: 26304740 DOI: 10.1038/ncomms9065] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/14/2015] [Indexed: 11/09/2022] Open
Abstract
Transcription errors occur in all living cells; however, it is unknown how these errors affect cellular health. To answer this question, we monitor yeast cells that are genetically engineered to display error-prone transcription. We discover that these cells suffer from a profound loss in proteostasis, which sensitizes them to the expression of genes that are associated with protein-folding diseases in humans; thus, transcription errors represent a new molecular mechanism by which cells can acquire disease phenotypes. We further find that the error rate of transcription increases as cells age, suggesting that transcription errors affect proteostasis particularly in aging cells. Accordingly, transcription errors accelerate the aggregation of a peptide that is implicated in Alzheimer's disease, and shorten the lifespan of cells. These experiments reveal a previously unappreciated role for transcriptional fidelity in cellular health and aging.
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Affiliation(s)
- Marc Vermulst
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA.,Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Ashley S Denney
- School of Medicine, University of Colorado, Denver, Colorado 80217, USA
| | - Michael J Lang
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Chao-Wei Hung
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Stephanie Moore
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - M Arthur Moseley
- Proteomics Core Facility, Duke University, Durham, North Carolina 27710, USA
| | - Arthur M Mosely
- Proteomics Core Facility, Duke University, Durham, North Carolina 27710, USA
| | - J Will Thompson
- Proteomics Core Facility, Duke University, Durham, North Carolina 27710, USA
| | - William J Thompson
- Proteomics Core Facility, Duke University, Durham, North Carolina 27710, USA
| | - Victoria Madden
- Microscopy Services Laboratory, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Jacob Gauer
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Katie J Wolfe
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Daniel W Summers
- Department of Developmental Biology, and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Jennifer Schleit
- Department of Pathology, University of Washington, Seattle, Washington 98195, USA
| | - George L Sutphin
- Department of Pathology, University of Washington, Seattle, Washington 98195, USA
| | - Suraiya Haroon
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Agnes Holczbauer
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Joanne Caine
- CSIRO, Department of Materials Science and Engineering, Parkville 3052, Australia
| | - James Jorgenson
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Douglas Cyr
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, Washington 98195, USA
| | - Jeffrey N Strathern
- Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, USA
| | - Mara C Duncan
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA.,Department of Chemistry, Curriculum in Applied Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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159
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Farrawell NE, Lambert-Smith IA, Warraich ST, Blair IP, Saunders DN, Hatters DM, Yerbury JJ. Distinct partitioning of ALS associated TDP-43, FUS and SOD1 mutants into cellular inclusions. Sci Rep 2015; 5:13416. [PMID: 26293199 PMCID: PMC4544019 DOI: 10.1038/srep13416] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 07/31/2015] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis is a rapidly progressing neurodegenerative disease associated with protein misfolding and aggregation. Most cases are characterized by TDP-43 positive inclusions, while a minority of familial ALS cases are instead FUS and SOD1 positive respectively. Cells can generate inclusions of variable type including previously characterized aggresomes, IPOD or JUNQ structures depending on the misfolded protein. SOD1 invariably forms JUNQ inclusions but it remains unclear whether other ALS protein aggregates arise as one of these previously described inclusion types or form unique structures. Here we show that FUS variably partitioned to IPOD, JUNQ or alternate structures, contain a mobile fraction, were not microtubule dependent and initially did not contain ubiquitin. TDP-43 inclusions formed in a microtubule independent manner, did not contain a mobile fraction but variably colocalized to JUNQ inclusions and another alternate structure. We conclude that the RNA binding proteins TDP-43 and FUS do not consistently fit the currently characterised inclusion models suggesting that cells have a larger repertoire for generating inclusions than currently thought, and imply that toxicity in ALS does not stem from a particular aggregation process or aggregate structure.
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Affiliation(s)
- Natalie E. Farrawell
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia
- Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Isabella A. Lambert-Smith
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia
- Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Sadaf T. Warraich
- Australian School of Advanced Medicine, Macquarie University, Sydney, NSW 2109, Australia
| | - Ian P. Blair
- Australian School of Advanced Medicine, Macquarie University, Sydney, NSW 2109, Australia
| | - Darren N. Saunders
- Cancer Division, Garvan Institute of Medical Research, The Kinghorn Cancer Centre, Darlinghurst NSW 2010, Australia
- St Vincent’s Clinical School, UNSW Medicine
| | | | - Justin J. Yerbury
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia
- Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522 Australia
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160
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Menezes R, Tenreiro S, Macedo D, Santos CN, Outeiro TF. From the baker to the bedside: yeast models of Parkinson's disease. MICROBIAL CELL 2015; 2:262-279. [PMID: 28357302 PMCID: PMC5349099 DOI: 10.15698/mic2015.08.219] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The baker’s yeast Saccharomyces cerevisiae has been extensively explored for our understanding of fundamental cell biology processes highly conserved in the eukaryotic kingdom. In this context, they have proven invaluable in the study of complex mechanisms such as those involved in a variety of human disorders. Here, we first provide a brief historical perspective on the emergence of yeast as an experimental model and on how the field evolved to exploit the potential of the model for tackling the intricacies of various human diseases. In particular, we focus on existing yeast models of the molecular underpinnings of Parkinson’s disease (PD), focusing primarily on the central role of protein quality control systems. Finally, we compile and discuss the major discoveries derived from these studies, highlighting their far-reaching impact on the elucidation of PD-associated mechanisms as well as in the identification of candidate therapeutic targets and compounds with therapeutic potential.
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Affiliation(s)
- Regina Menezes
- Instituto de Biologia Experimental e Tecnológica, Apartado 12, Oeiras 2781-901, Portugal. ; Instituto de Tecnologia Química e Biológica António Xavier, Av. da República, 2780-157 Oeiras, Universidade Nova de Lisboa, Portugal
| | - Sandra Tenreiro
- Instituto de Medicina Molecular, Av. Prof. Egas Moniz, Lisboa 1649-028, Portugal. ; CEDOC - Chronic Diseases Research Center, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, Lisboa 1169-056, Portugal
| | - Diana Macedo
- Instituto de Tecnologia Química e Biológica António Xavier, Av. da República, 2780-157 Oeiras, Universidade Nova de Lisboa, Portugal
| | - Cláudia N Santos
- Instituto de Biologia Experimental e Tecnológica, Apartado 12, Oeiras 2781-901, Portugal. ; Instituto de Tecnologia Química e Biológica António Xavier, Av. da República, 2780-157 Oeiras, Universidade Nova de Lisboa, Portugal
| | - Tiago F Outeiro
- Instituto de Fisiologia, Faculdade de Medicina da Universidade de Lisboa, Lisboa 1649-028, Portugal. ; CEDOC - Chronic Diseases Research Center, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, Lisboa 1169-056, Portugal. ; Department of NeuroDegeneration and Restorative Research, University Medical Center Göttingen, Waldweg 33, Göttingen 37073, Germany
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161
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Chou CC, Alexeeva OM, Yamada S, Pribadi A, Zhang Y, Mo B, Williams KR, Zarnescu DC, Rossoll W. PABPN1 suppresses TDP-43 toxicity in ALS disease models. Hum Mol Genet 2015; 24:5154-73. [PMID: 26130692 DOI: 10.1093/hmg/ddv238] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 06/22/2015] [Indexed: 12/13/2022] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) is a major disease protein in amyotrophic lateral sclerosis (ALS) and related neurodegenerative diseases. Both the cytoplasmic accumulation of toxic ubiquitinated and hyperphosphorylated TDP-43 fragments and the loss of normal TDP-43 from the nucleus may contribute to the disease progression by impairing normal RNA and protein homeostasis. Therefore, both the removal of pathological protein and the rescue of TDP-43 mislocalization may be critical for halting or reversing TDP-43 proteinopathies. Here, we report poly(A)-binding protein nuclear 1 (PABPN1) as a novel TDP-43 interaction partner that acts as a potent suppressor of TDP-43 toxicity. Overexpression of full-length PABPN1 but not a truncated version lacking the nuclear localization signal protects from pathogenic TDP-43-mediated toxicity, promotes the degradation of pathological TDP-43 and restores normal solubility and nuclear localization of endogenous TDP-43. Reduced levels of PABPN1 enhances the phenotypes in several cell culture and Drosophila models of ALS and results in the cytoplasmic mislocalization of TDP-43. Moreover, PABPN1 rescues the dysregulated stress granule (SG) dynamics and facilitates the removal of persistent SGs in TDP-43-mediated disease conditions. These findings demonstrate a role for PABPN1 in rescuing several cytopathological features of TDP-43 proteinopathy by increasing the turnover of pathologic proteins.
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Affiliation(s)
- Ching-Chieh Chou
- Department of Cell Biology, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Shizuka Yamada
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA and
| | - Amy Pribadi
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA and
| | - Yi Zhang
- Department of Cell Biology, Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Bi Mo
- Department of Cell Biology
| | | | - Daniela C Zarnescu
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA and
| | - Wilfried Rossoll
- Department of Cell Biology, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA 30322, USA,
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162
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Kao PF, Chen YR, Liu XB, DeCarli C, Seeley WW, Jin LW. Detection of TDP-43 oligomers in frontotemporal lobar degeneration-TDP. Ann Neurol 2015; 78:211-21. [PMID: 25921485 DOI: 10.1002/ana.24431] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 04/22/2015] [Accepted: 04/22/2015] [Indexed: 12/11/2022]
Abstract
OBJECTIVE The proteinaceous inclusions in TDP-43 proteinopathies such as frontotemporal lobar degeneration (FTLD)-TDP are made of high-molecular-weight aggregates of TDP-43. These aggregates have not been classified as amyloids, as prior amyloid staining results were not conclusive. Here we used a specific TDP-43 amyloid oligomer antibody called TDP-O to determine the presence and abundance of TDP-43 oligomers among different subtypes of FTLD-TDP as well as in hippocampal sclerosis (HS), which represents a non-FTLD pathology with TDP-43 inclusions. METHODS Postmortem tissue from the hippocampus and anterior orbital gyrus from 54 prospectively assessed and diagnosed subjects was used for immunostaining with TDP-O. Electron microscopy was used to assess the subcellular locations of TDP-O-decorated structures. RESULTS TDP-43 inclusions staining with TDP-O were present in FTLD-TDP and were most conspicuous for FTLD-TDP type C, the subtype seen in most patients with semantic variant primary progressive aphasia. TDP-O immunoreactivity was absent in the hippocampus of HS patients despite abundant TDP-43 inclusions. Ultrastructurally, TDP-43 oligomers resided in granular or tubular structures, frequently in close proximity to, but not within, neuronal lysosomes. INTERPRETATION TDP-43 forms amyloid oligomers in the human brain, which may cause neurotoxicity in a manner similar to other amyloid oligomers. Oligomer formation may contribute to the conformational heterogeneity of TDP-43 aggregates and mark the different properties of TDP-43 inclusions between FTLD-TDP and HS.
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Affiliation(s)
- Patricia F Kao
- Department of Pathology and Laboratory Medicine, University of California, Davis, School of Medicine, Sacramento, CA.,Alzheimer's Disease Center, University of California, Davis, School of Medicine, Sacramento, CA
| | - Yun-Ru Chen
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Xiao-Bo Liu
- Department of Pathology and Laboratory Medicine, University of California, Davis, School of Medicine, Sacramento, CA
| | - Charles DeCarli
- Alzheimer's Disease Center, University of California, Davis, School of Medicine, Sacramento, CA.,Department of Neurology, University of California, Davis, School of Medicine, Sacramento, CA
| | - William W Seeley
- Departments of Neurology and Pathology, University of California, San Francisco, San Francisco, CA
| | - Lee-Way Jin
- Department of Pathology and Laboratory Medicine, University of California, Davis, School of Medicine, Sacramento, CA.,Alzheimer's Disease Center, University of California, Davis, School of Medicine, Sacramento, CA
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163
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Bonanomi M, Visentin C, Invernizzi G, Tortora P, Regonesi ME. The Toxic Effects of Pathogenic Ataxin-3 Variants in a Yeast Cellular Model. PLoS One 2015; 10:e0129727. [PMID: 26052945 PMCID: PMC4460139 DOI: 10.1371/journal.pone.0129727] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 05/12/2015] [Indexed: 12/22/2022] Open
Abstract
Ataxin-3 (AT3) is a deubiquitinating enzyme that triggers an inherited neurodegenerative disorder, spinocerebellar ataxia type 3, when its polyglutamine (polyQ) stretch close to the C-terminus exceeds a critical length. AT3 variants carrying the expanded polyQ are prone to associate with each other into amyloid toxic aggregates, which are responsible for neuronal death with ensuing neurodegeneration. We employed Saccharomyces cerevisiae as a eukaryotic cellular model to better clarify the mechanism by which AT3 triggers the disease. We expressed three variants: one normal (Q26), one expanded (Q85) and one truncated for a region lying from the beginning of its polyQ stretch to the end of the protein (291Δ). We found that the expression of the expanded form caused reduction in viability, accumulation of reactive oxygen species, imbalance of the antioxidant defense system and loss in cell membrane integrity, leading to necrotic death. The truncated variant also exerted a qualitatively similar, albeit milder, effect on cell growth and cytotoxicity, which points to the involvement of also non-polyQ regions in cytotoxicity. Guanidine hydrochloride, a well-known inhibitor of the chaperone Hsp104, almost completely restored wild-type survival rate of both 291Δ- and Q85-expressing strains. This suggests that AT3 aggregation and toxicity is mediated by prion forms of yeast proteins, as this chaperone plays a key role in their propagation.
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Affiliation(s)
- Marcella Bonanomi
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Cristina Visentin
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Gaetano Invernizzi
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Paolo Tortora
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy
- Milan Center of Neuroscience (NeuroMI), Milan, Italy
- * E-mail:
| | - Maria Elena Regonesi
- Milan Center of Neuroscience (NeuroMI), Milan, Italy
- Department of Statistics and Quantitative Methods, University of Milano-Bicocca, Milan, Italy
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164
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Highley JR, Kirby J, Jansweijer JA, Webb PS, Hewamadduma CA, Heath PR, Higginbottom A, Raman R, Ferraiuolo L, Cooper-Knock J, McDermott CJ, Wharton SB, Shaw PJ, Ince PG. Loss of nuclear TDP-43 in amyotrophic lateral sclerosis (ALS) causes altered expression of splicing machinery and widespread dysregulation of RNA splicing in motor neurones. Neuropathol Appl Neurobiol 2015; 40:670-85. [PMID: 24750229 DOI: 10.1111/nan.12148] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 04/04/2014] [Indexed: 12/14/2022]
Abstract
AIMS Loss of nuclear TDP-43 characterizes sporadic and most familial forms of amyotrophic lateral sclerosis (ALS). TDP-43 (encoded by TARDBP) has multiple roles in RNA processing. We aimed to determine whether (1) RNA splicing dysregulation is present in lower motor neurones in ALS and in a motor neurone-like cell model; and (2) TARDBP mutations (mtTARDBP) are associated with aberrant RNA splicing using patient-derived fibroblasts. METHODS Affymetrix exon arrays were used to study mRNA expression and splicing in lower motor neurones obtained by laser capture microdissection of autopsy tissue from individuals with sporadic ALS and TDP-43 proteinopathy. Findings were confirmed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and in NSC34 motor neuronal cells following shRNA-mediated TDP-43 depletion. Exon arrays and immunohistochemistry were used to study mRNA splicing and TDP-43 expression in fibroblasts from patients with mtTARDBP-associated, sporadic and mutant SOD1-associated ALS. RESULTS We found altered expression of spliceosome components in motor neurones and widespread aberrations of mRNA splicing that specifically affected genes involved in ribonucleotide binding. This was confirmed in TDP-43-depleted NSC34 cells. Fibroblasts with mtTARDBP showed loss of nuclear TDP-43 protein and demonstrated similar changes in splicing and gene expression, which were not present in fibroblasts from patients with sporadic or SOD1-related ALS. CONCLUSION Loss of nuclear TDP-43 is associated with RNA processing abnormalities in ALS motor neurones, patient-derived cells with mtTARDBP, and following artificial TDP-43 depletion, suggesting that splicing dysregulation directly contributes to disease pathogenesis. Key functional pathways affected include those central to RNA metabolism.
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Affiliation(s)
- J Robin Highley
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
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165
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Smethurst P, Sidle KCL, Hardy J. Review: Prion-like mechanisms of transactive response DNA binding protein of 43 kDa (TDP-43) in amyotrophic lateral sclerosis (ALS). Neuropathol Appl Neurobiol 2015; 41:578-97. [PMID: 25487060 DOI: 10.1111/nan.12206] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/03/2014] [Indexed: 01/13/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal devastating neurodegenerative disorder which predominantly affects the motor neurons in the brain and spinal cord. The death of the motor neurons in ALS causes subsequent muscle atrophy, paralysis and eventual death. Clinical and biological evidence now demonstrates that ALS has many similarities to prion disease in terms of disease onset, phenotype variability and progressive spread. The pathognomonic ubiquitinated inclusions deposited in the neurons and glial cells in brains and spinal cords of patients with ALS and fronto-temporal lobar degeneration with ubiquitinated inclusions contain aggregated transactive response DNA binding protein of 43 kDa (TDP-43), and evidence now suggests that TDP-43 has cellular prion-like properties. The cellular mechanisms of prion protein misfolding and aggregation are thought to be responsible for the characteristics of prion disease. Therefore, there is a strong mechanistic basis for a prion-like behaviour of the TDP-43 protein being responsible for some characteristics of ALS. In this review, we compare the prion-like mechanisms of TDP-43 to the clinical and biological nature of ALS in order to investigate how this protein could be responsible for some of the characteristic properties of the disease.
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Affiliation(s)
- Phillip Smethurst
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square House, London, UK
| | | | - John Hardy
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square House, London, UK
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166
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Sanhueza M, Chai A, Smith C, McCray BA, Simpson TI, Taylor JP, Pennetta G. Network analyses reveal novel aspects of ALS pathogenesis. PLoS Genet 2015; 11:e1005107. [PMID: 25826266 PMCID: PMC4380362 DOI: 10.1371/journal.pgen.1005107] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 02/27/2015] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease characterized by selective loss of motor neurons, muscle atrophy and paralysis. Mutations in the human VAMP-associated protein B (hVAPB) cause a heterogeneous group of motor neuron diseases including ALS8. Despite extensive research, the molecular mechanisms underlying ALS pathogenesis remain largely unknown. Genetic screens for key interactors of hVAPB activity in the intact nervous system, however, represent a fundamental approach towards understanding the in vivo function of hVAPB and its role in ALS pathogenesis. Targeted expression of the disease-causing allele leads to neurodegeneration and progressive decline in motor performance when expressed in the adult Drosophila, eye or in its entire nervous system, respectively. By using these two phenotypic readouts, we carried out a systematic survey of the Drosophila genome to identify modifiers of hVAPB-induced neurotoxicity. Modifiers cluster in a diverse array of biological functions including processes and genes that have been previously linked to hVAPB function, such as proteolysis and vesicular trafficking. In addition to established mechanisms, the screen identified endocytic trafficking and genes controlling proliferation and apoptosis as potent modifiers of ALS8-mediated defects. Surprisingly, the list of modifiers was mostly enriched for proteins linked to lipid droplet biogenesis and dynamics. Computational analysis reveals that most modifiers can be linked into a complex network of interacting genes, and that the human genes homologous to the Drosophila modifiers can be assembled into an interacting network largely overlapping with that in flies. Identity markers of the endocytic process were also found to abnormally accumulate in ALS patients, further supporting the relevance of the fly data for human biology. Collectively, these results not only lead to a better understanding of hVAPB function but also point to potentially relevant targets for therapeutic intervention. Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease causing loss of motor neurons and consequently a progressive deterioration of motor functions. ALS is uniformly fatal with death occurring 5 years after onset of symptoms. There is currently no effective treatment for ALS. Several mutations in a gene called hVAPB have shown that this gene is causative of a type of ALS known as ALS8. In this study we sought to identify genes and cellular processes that are involved in the toxicity conferred by the defective ALS8 allele. By using the power of Drosophila genetics, we performed a large scale genomic screen and identified a number of genes that can affect hVAPB-mediated toxicity. These modifiers cluster into functional pathways known to be involved in ALS as well as novel ones. The relevance of these modifiers and mechanisms for the human disease was confirmed by showing that the human homologues of the fly modifiers can be organized into a network that closely resembles that of the Drosophila genes. Identifying cellular processes and proteins that modulate hVAPB pathological activity can facilitate the discovery of an effective treatment for ALS.
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Affiliation(s)
- Mario Sanhueza
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
- Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrea Chai
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
- Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Houston, Texas, United States of America
| | - Colin Smith
- Academic Department of Neuropathology, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Brett A. McCray
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - T. Ian Simpson
- Biomathematics and Statistics Scotland, University of Edinburgh, United Kingdom
- Institute for Adaptive and Neural Computation, School of Informatics, University of Edinburgh, United Kingdom
| | - J. Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Giuseppa Pennetta
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
- Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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167
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Oyanagi K, Yamazaki M, Hashimoto T, Asakawa M, Wakabayashi K, Takahashi H. Hippocampal sclerosis in the parkinsonism-dementia complex of Guam: quantitative examination of neurons, neurofibrillary tangles, and TDP-43 immunoreactivity in CA1. Neuropathology 2015; 35:224-35. [PMID: 25783521 DOI: 10.1111/neup.12185] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 10/21/2014] [Accepted: 10/22/2014] [Indexed: 01/23/2023]
Abstract
The cornu ammonis 1 (CA1) area in the hippocampus of the parkinsonism-dementia complex (PDC) of Guam was examined quantitatively with special references to the number of neurons, intraneuronal (i) and extracellular (e) neurofibirillary tangles (NFTs), and TDP-43 (43-kDa trans-activation-responsive region DNA-binding protein)-immunopositive structures, in 24 Chamorro patients with PDC of Guam and seven control Chamorro Guamanians (both groups having no ischemic or anoxic complications). The results were that: (i) in the patients with mildly involved PDC, total numbers of neurons, iNFTs and eNFTs were almost the same as those of neurons of controls; (ii) in patients severely involved, total numbers of neurons, iNFTs and eNFTs decreased markedly; (iii) the decrease of the number of pyramidal neurons in CA1 with positive nuclear TDP-43 was intimately correlated with the decrease in total neuron numbers; (iv) whereas the numbers of neurons and TDP-43-immunopositive intracytoplasmic aggregation in the CA1 area were inversely correlated; and (v) depression of nuclear TDP-43 immuonostainability was not affected by the presence or absence of NFTs. In conclusion, hippocampal sclerosis exists in PDC; there is a possibility of elimination of eNFTs which appeared in the CA1 in patients with PDC and loss of the neurons correlates with disappearance of nuclear TDP-43, but not with appearance of intraneurocytoplasmic TDP-43 aggregation or iNFTs.
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Affiliation(s)
- Kiyomitsu Oyanagi
- Department of Brain Disease Research, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Mineo Yamazaki
- Department of Neurology, Nippon Medical School Chiba Hokusoh Hospital, Inzai, Chiba, Japan
| | - Tomoyo Hashimoto
- Department of Brain Disease Research, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.,Department of Neurology, University of Occupational and Environmental Health, Kitakyushu, Fukuoka, Japan
| | - Mika Asakawa
- Department of Brain Disease Research, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Koichi Wakabayashi
- Department of Neuropathology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Hitoshi Takahashi
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, Niigata, Japan
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168
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Braun RJ. Ubiquitin-dependent proteolysis in yeast cells expressing neurotoxic proteins. Front Mol Neurosci 2015; 8:8. [PMID: 25814926 PMCID: PMC4357299 DOI: 10.3389/fnmol.2015.00008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 02/24/2015] [Indexed: 01/16/2023] Open
Abstract
Critically impaired protein degradation is discussed to contribute to neurodegenerative disorders, including Parkinson's, Huntington's, Alzheimer's, and motor neuron diseases. Misfolded, aggregated, or surplus proteins are efficiently degraded via distinct protein degradation pathways, including the ubiquitin-proteasome system, autophagy, and vesicular trafficking. These pathways are regulated by covalent modification of target proteins with the small protein ubiquitin and are evolutionary highly conserved from humans to yeast. The yeast Saccharomyces cerevisiae is an established model for deciphering mechanisms of protein degradation, and for the elucidation of pathways underlying programmed cell death. The expression of human neurotoxic proteins triggers cell death in yeast, with neurotoxic protein-specific differences. Therefore, yeast cell death models are suitable for analyzing the role of protein degradation pathways in modulating cell death upon expression of disease-causing proteins. This review summarizes which protein degradation pathways are affected in these yeast models, and how they are involved in the execution of cell death. I will discuss to which extent this mimics the situation in other neurotoxic models, and how this may contribute to a better understanding of human disorders.
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Affiliation(s)
- Ralf J Braun
- Institut für Zellbiologie, Universität Bayreuth Bayreuth, Germany
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169
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Grad LI, Fernando SM, Cashman NR. From molecule to molecule and cell to cell: prion-like mechanisms in amyotrophic lateral sclerosis. Neurobiol Dis 2015; 77:257-65. [PMID: 25701498 DOI: 10.1016/j.nbd.2015.02.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 08/13/2014] [Accepted: 02/09/2015] [Indexed: 12/12/2022] Open
Abstract
Prions, self-proliferating infectious agents consisting of misfolded protein, are most often associated with aggressive neurodegenerative diseases in animals and humans. Akin to the contiguous spread of a living pathogen, the prion paradigm provides a mechanism by which a mutant or wild-type misfolded protein can dominate pathogenesis through self-propagating protein misfolding, and subsequently spread from region to region through the central nervous system. The prion diseases, along with more common neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and the tauopathies belong to a larger group of protein misfolding disorders termed proteinopathies that feature aberrant misfolding and aggregation of specific proteins. Amyotrophic lateral sclerosis (ALS), a lethal disease characterized by progressive degeneration of motor neurons is currently understood as a classical proteinopathy; the disease is typified by the formation of inclusions consisting of aggregated protein within motor neurons that contribute to neurotoxicity. It is well established that misfolded/aggregated proteins such as SOD1 and TDP-43 contribute to the toxicity of motor neurons and play a prominent role in the pathology of ALS. Recent work has identified propagated protein misfolding properties in both mutant and wild-type SOD1, and to a lesser extent TDP-43, which may provide the molecular basis for the clinically observed contiguous spread of the disease through the neuroaxis. In this review we examine the current state of knowledge regarding the prion-like properties of proteins associated with ALS pathology as well as their possible mechanisms of transmission.
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Affiliation(s)
- Leslie I Grad
- Department of Medicine (Neurology), Brain Research Centre, University of British Columbia, 2211 Wesbrook Mall, Vancouver BC, Canada, V6T 2B5
| | - Sarah M Fernando
- Department of Medicine (Neurology), Brain Research Centre, University of British Columbia, 2211 Wesbrook Mall, Vancouver BC, Canada, V6T 2B5
| | - Neil R Cashman
- Department of Medicine (Neurology), Brain Research Centre, University of British Columbia, 2211 Wesbrook Mall, Vancouver BC, Canada, V6T 2B5.
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170
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Hartman JL, Stisher C, Outlaw DA, Guo J, Shah NA, Tian D, Santos SM, Rodgers JW, White RA. Yeast Phenomics: An Experimental Approach for Modeling Gene Interaction Networks that Buffer Disease. Genes (Basel) 2015; 6:24-45. [PMID: 25668739 PMCID: PMC4377832 DOI: 10.3390/genes6010024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 01/12/2015] [Indexed: 01/10/2023] Open
Abstract
The genome project increased appreciation of genetic complexity underlying disease phenotypes: many genes contribute each phenotype and each gene contributes multiple phenotypes. The aspiration of predicting common disease in individuals has evolved from seeking primary loci to marginal risk assignments based on many genes. Genetic interaction, defined as contributions to a phenotype that are dependent upon particular digenic allele combinations, could improve prediction of phenotype from complex genotype, but it is difficult to study in human populations. High throughput, systematic analysis of S. cerevisiae gene knockouts or knockdowns in the context of disease-relevant phenotypic perturbations provides a tractable experimental approach to derive gene interaction networks, in order to deduce by cross-species gene homology how phenotype is buffered against disease-risk genotypes. Yeast gene interaction network analysis to date has revealed biology more complex than previously imagined. This has motivated the development of more powerful yeast cell array phenotyping methods to globally model the role of gene interaction networks in modulating phenotypes (which we call yeast phenomic analysis). The article illustrates yeast phenomic technology, which is applied here to quantify gene X media interaction at higher resolution and supports use of a human-like media for future applications of yeast phenomics for modeling human disease.
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Affiliation(s)
- John L Hartman
- Department of Genetics, University of Alabama at Birmingham, 730 Hugh Kaul Human Genetics Building, 720 20th Street South, Birmingham, AL 35294, USA.
| | - Chandler Stisher
- Department of Genetics, University of Alabama at Birmingham, 730 Hugh Kaul Human Genetics Building, 720 20th Street South, Birmingham, AL 35294, USA.
| | - Darryl A Outlaw
- Department of Genetics, University of Alabama at Birmingham, 730 Hugh Kaul Human Genetics Building, 720 20th Street South, Birmingham, AL 35294, USA.
| | - Jingyu Guo
- Department of Genetics, University of Alabama at Birmingham, 730 Hugh Kaul Human Genetics Building, 720 20th Street South, Birmingham, AL 35294, USA.
| | - Najaf A Shah
- Department of Genetics, University of Alabama at Birmingham, 730 Hugh Kaul Human Genetics Building, 720 20th Street South, Birmingham, AL 35294, USA.
| | - Dehua Tian
- Department of Genetics, University of Alabama at Birmingham, 730 Hugh Kaul Human Genetics Building, 720 20th Street South, Birmingham, AL 35294, USA.
| | - Sean M Santos
- Department of Genetics, University of Alabama at Birmingham, 730 Hugh Kaul Human Genetics Building, 720 20th Street South, Birmingham, AL 35294, USA.
| | - John W Rodgers
- Department of Genetics, University of Alabama at Birmingham, 730 Hugh Kaul Human Genetics Building, 720 20th Street South, Birmingham, AL 35294, USA.
| | - Richard A White
- Department of Statistics and Michael Smith Laboratories, University of British Columbia, 3182 Earth Sciences Building, 2207 Main Mall, Vancouver, BC V6T-1Z4, Canada.
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171
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Amen T, Kaganovich D. Dynamic droplets: the role of cytoplasmic inclusions in stress, function, and disease. Cell Mol Life Sci 2015; 72:401-415. [PMID: 25283146 PMCID: PMC11113435 DOI: 10.1007/s00018-014-1740-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/16/2014] [Accepted: 09/22/2014] [Indexed: 12/12/2022]
Abstract
Neurodegenerative diseases and other proteinopathies constitute a class of several dozen illnesses etiologically linked to pathological protein misfolding and aggregation. Because of this strong association with disease pathology, cell death, and aging, accumulation of proteins in aggregates or aggregation-associated structures (inclusions) has come to be regarded by many as a deleterious process, to be avoided if possible. Recent work has led us to see inclusion structures and disordered aggregate-like protein mixtures (which we call dynamic droplets) in a new light: not necessarily as a result of a pathological breakdown of cellular order, but as an elaborate cellular architecture regulating function and stress response. In this review, we discuss what is currently known about the role of inclusion structures in cellular homeostasis, stress response, toxicity, and disease. We will focus on possible mechanisms of aggregate toxicity, in contrast to the homeostatic function of several inclusion structures.
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Affiliation(s)
- Triana Amen
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Alexander Grass Center for Bioengineering, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Daniel Kaganovich
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
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172
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Arslan F, Hong JY, Kanneganti V, Park SK, Liebman SW. Heterologous aggregates promote de novo prion appearance via more than one mechanism. PLoS Genet 2015; 11:e1004814. [PMID: 25568955 PMCID: PMC4287349 DOI: 10.1371/journal.pgen.1004814] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 10/09/2014] [Indexed: 12/12/2022] Open
Abstract
Prions are self-perpetuating conformational variants of particular proteins. In yeast, prions cause heritable phenotypic traits. Most known yeast prions contain a glutamine (Q)/asparagine (N)-rich region in their prion domains. [PSI+], the prion form of Sup35, appears de novo at dramatically enhanced rates following transient overproduction of Sup35 in the presence of [PIN+], the prion form of Rnq1. Here, we establish the temporal de novo appearance of Sup35 aggregates during such overexpression in relation to other cellular proteins. Fluorescently-labeled Sup35 initially forms one or a few dots when overexpressed in [PIN+] cells. One of the dots is perivacuolar, colocalizes with the aggregated Rnq1 dot and grows into peripheral rings/lines, some of which also colocalize with Rnq1. Sup35 dots that are not near the vacuole do not always colocalize with Rnq1 and disappear by the time rings start to grow. Bimolecular fluorescence complementation failed to detect any interaction between Sup35-VN and Rnq1-VC in [PSI+][PIN+] cells. In contrast, all Sup35 aggregates, whether newly induced or in established [PSI+], completely colocalize with the molecular chaperones Hsp104, Sis1, Ssa1 and eukaryotic release factor Sup45. In the absence of [PIN+], overexpressed aggregating proteins such as the Q/N-rich Pin4C or the non-Q/N-rich Mod5 can also promote the de novo appearance of [PSI+]. Similar to Rnq1, overexpressed Pin4C transiently colocalizes with newly appearing Sup35 aggregates. However, no interaction was detected between Mod5 and Sup35 during [PSI+] induction in the absence of [PIN+]. While the colocalization of Sup35 and aggregates of Rnq1 or Pin4C are consistent with the model that the heterologous aggregates cross-seed the de novo appearance of [PSI+], the lack of interaction between Mod5 and Sup35 leaves open the possibility of other mechanisms. We also show that Hsp104 is required in the de novo appearance of [PSI+] aggregates in a [PIN+]-independent pathway. Certain proteins can misfold into β-sheet-rich, self-seeding aggregates. Such proteins appear to be associated with neurodegenerative diseases such as prion, Alzheimer's and Parkinson's. Yeast prions also misfold into self-seeding aggregates and provide a good model to study how these rogue polymers first appear. De novo prion appearance can be made very frequent in yeast by transient overexpression of the prion protein in the presence of heterologous prions or prion-like aggregates. Here, we show that the aggregates of one such newly induced prion are initially formed in a dot-like structure near the vacuole. These dots then grow into rings at the periphery of the cell prior to becoming smaller rings surrounding the vacuole and maturing into the characteristic heritable prion tiny dots found throughout the cytoplasm. We found considerable colocalization of two heterologous prion/prion-like aggregates with the newly appearing prion protein aggregates, which is consistent with the prevalent model that existing prion aggregates can cross-seed the de novo aggregation of a heterologous prion protein. However, we failed to find any physical interaction between another heterologous aggregating protein and the newly appearing prion aggregates it stimulated to appear, which is inconsistent with cross-seeding.
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Affiliation(s)
- Fatih Arslan
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
| | - Joo Y. Hong
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
| | - Vydehi Kanneganti
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
| | - Sei-Kyoung Park
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
| | - Susan W. Liebman
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
- * E-mail:
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173
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Lee S, Lee TA, Lee E, Kang S, Park A, Kim SW, Park HJ, Yoon JH, Ha SJ, Park T, Lee JS, Cheon JH, Park B. Identification of a subnuclear body involved in sequence-specific cytokine RNA processing. Nat Commun 2015; 6:5791. [PMID: 25557830 DOI: 10.1038/ncomms6791] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 11/06/2014] [Indexed: 12/29/2022] Open
Abstract
Processing of interleukin RNAs must be tightly controlled during the immune response. Here we report that a subnuclear body called the interleukin-6 and -10 splicing activating compartment (InSAC) is a nuclear site of cytokine RNA production and stability. Tat-activating regulatory DNA-binding protein-43 (TDP-43) acts as an InSAC scaffold that selectively associates with IL-6 and IL-10 RNAs in a sequence-specific manner. TDP-43 also recruits key spliceosomal components from Cajal bodies. LPS induces posttranslational modifications of TDP-43; in particular, TDP-43 ubiquitination provides a driving force for InSAC formation. As a consequence, in vivo depletion of TDP-43 leads to a dramatic reduction in the RNA processing and the protein levels of IL-6 in serum. Collectively, our findings highlight the importance of TDP-43-mediated InSAC biogenesis in immune regulation.
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Affiliation(s)
- Sungwook Lee
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, South Korea
| | - Taeyun A Lee
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, South Korea
| | - Eunhye Lee
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, South Korea
| | - Sujin Kang
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, South Korea
| | - Areum Park
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, South Korea
| | - Seung Won Kim
- 1] Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, Seoul 120-752, South Korea [2] Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, South Korea
| | - Hyo Jin Park
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, South Korea
| | - Je-Hyun Yoon
- Laboratory of Genetics, National Institute on Aging-Intramural Research Program, NIH, Baltimore, Maryland 21224, USA
| | - Sang-Jun Ha
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, South Korea
| | - Taesun Park
- Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul 120-749, South Korea
| | - Ju-Seog Lee
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, USA
| | - Jae Hee Cheon
- 1] Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, Seoul 120-752, South Korea [2] Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, South Korea
| | - Boyoun Park
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, South Korea
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174
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Feligioni M, Marcelli S, Knock E, Nadeem U, Arancio O, E. Fraser P. SUMO modulation of protein aggregation and degradation. AIMS MOLECULAR SCIENCE 2015. [DOI: 10.3934/molsci.2015.4.382] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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175
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Jackrel ME, Tariq A, Yee K, Weitzman R, Shorter J. Isolating potentiated Hsp104 variants using yeast proteinopathy models. J Vis Exp 2014:e52089. [PMID: 25407485 DOI: 10.3791/52089] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Many protein-misfolding disorders can be modeled in the budding yeast Saccharomyces cerevisiae. Proteins such as TDP-43 and FUS, implicated in amyotrophic lateral sclerosis, and α-synuclein, implicated in Parkinson's disease, are toxic and form cytoplasmic aggregates in yeast. These features recapitulate protein pathologies observed in patients with these disorders. Thus, yeast are an ideal platform for isolating toxicity suppressors from libraries of protein variants. We are interested in applying protein disaggregases to eliminate misfolded toxic protein conformers. Specifically, we are engineering Hsp104, a hexameric AAA+ protein from yeast that is uniquely capable of solubilizing both disordered aggregates and amyloid and returning the proteins to their native conformations. While Hsp104 is highly conserved in eukaryotes and eubacteria, it has no known metazoan homologue. Hsp104 has only limited ability to eliminate disordered aggregates and amyloid fibers implicated in human disease. Thus, we aim to engineer Hsp104 variants to reverse the protein misfolding implicated in neurodegenerative disorders. We have developed methods to screen large libraries of Hsp104 variants for suppression of proteotoxicity in yeast. As yeast are prone to spontaneous nonspecific suppression of toxicity, a two-step screening process has been developed to eliminate false positives. Using these methods, we have identified a series of potentiated Hsp104 variants that potently suppress the toxicity and aggregation of TDP-43, FUS, and α-synuclein. Here, we describe this optimized protocol, which could be adapted to screen libraries constructed using any protein backbone for suppression of toxicity of any protein that is toxic in yeast.
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Affiliation(s)
- Meredith E Jackrel
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania
| | - Amber Tariq
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania
| | - Keolamau Yee
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania
| | - Rachel Weitzman
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania;
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176
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Suzuki H, Shibagaki Y, Hattori S, Matsuoka M. Nuclear TDP-43 causes neuronal toxicity by escaping from the inhibitory regulation by hnRNPs. Hum Mol Genet 2014; 24:1513-27. [DOI: 10.1093/hmg/ddu563] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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177
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Couthouis J, Raphael AR, Daneshjou R, Gitler AD. Targeted exon capture and sequencing in sporadic amyotrophic lateral sclerosis. PLoS Genet 2014; 10:e1004704. [PMID: 25299611 PMCID: PMC4191946 DOI: 10.1371/journal.pgen.1004704] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 08/25/2014] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease that results in progressive degeneration of motor neurons, ultimately leading to paralysis and death. Approximately 10% of ALS cases are familial, with the remaining 90% of cases being sporadic. Genetic studies in familial cases of ALS have been extremely informative in determining the causative mutations behind ALS, especially as the same mutations identified in familial ALS can also cause sporadic disease. However, the cause of ALS in approximately 30% of familial cases and in the majority of sporadic cases remains unknown. Sporadic ALS cases represent an underutilized resource for genetic information about ALS; therefore, we undertook a targeted sequencing approach of 169 known and candidate ALS disease genes in 242 sporadic ALS cases and 129 matched controls to try to identify novel variants linked to ALS. We found a significant enrichment in novel and rare variants in cases versus controls, indicating that we are likely identifying disease associated mutations. This study highlights the utility of next generation sequencing techniques combined with functional studies and rare variant analysis tools to provide insight into the genetic etiology of a heterogeneous sporadic disease. Amyotrophic lateral sclerosis (ALS), also known as Charcot disease or Lou Gehrig's disease, is one of the most common neuromuscular diseases worldwide. This disease is characterized by a progressive degeneration of motor neurons, leading to patient death within a few years after onset. Despite the fact that most ALS cases are sporadic, most of the ALS genetic studies have focused on familial forms, leading to the genetic determination of cause for 70% of cases of familial ALS but for only 10% of sporadic ALS cases. This, coupled with the dearth of families available for study, suggests that researchers should begin tapping into the relatively untouched reservoir of available sporadic samples to identify novel genetic causes of sporadic ALS. Here we take advantage of high-throughput target sequencing techniques to test four different hypotheses about the genetic causes of ALS in sporadic ALS and uncover new candidate genes and pathways implicated in ALS.
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Affiliation(s)
- Julien Couthouis
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Alya R. Raphael
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Roxana Daneshjou
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Aaron D. Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail:
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178
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Fang YS, Tsai KJ, Chang YJ, Kao P, Woods R, Kuo PH, Wu CC, Liao JY, Chou SC, Lin V, Jin LW, Yuan HS, Cheng IH, Tu PH, Chen YR. Full-length TDP-43 forms toxic amyloid oligomers that are present in frontotemporal lobar dementia-TDP patients. Nat Commun 2014; 5:4824. [PMID: 25215604 DOI: 10.1038/ncomms5824] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 07/25/2014] [Indexed: 12/12/2022] Open
Abstract
Proteinaceous inclusions are common hallmarks of many neurodegenerative diseases. TDP-43 proteinopathies, consisting of several neurodegenerative diseases, including frontotemporal lobar dementia (FTLD) and amyotrophic lateral sclerosis (ALS), are characterized by inclusion bodies formed by polyubiquitinated and hyperphosphorylated full-length and truncated TDP-43. The structural properties of TDP-43 aggregates and their relationship to pathogenesis are still ambiguous. Here we demonstrate that the recombinant full-length human TDP-43 forms structurally stable, spherical oligomers that share common epitopes with an anti-amyloid oligomer-specific antibody. The TDP-43 oligomers are stable, have exposed hydrophobic surfaces, exhibit reduced DNA binding capability and are neurotoxic in vitro and in vivo. Moreover, TDP-43 oligomers are capable of cross-seeding Alzheimer's amyloid-β to form amyloid oligomers, demonstrating interconvertibility between the amyloid species. Such oligomers are present in the forebrain of transgenic TDP-43 mice and FTLD-TDP patients. Our results suggest that aside from filamentous aggregates, TDP-43 oligomers may play a role in TDP-43 pathogenesis.
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Affiliation(s)
- Yu-Sheng Fang
- 1] Genomics Research Center, Academia Sinica, 128, Academia Road, Section 2, Nankang District, Taipei 115, Taiwan [2] Institute of Bioinformatics and Structural Biology, National Tsing Hua University, 101, Kuang fu Road, Section 2, Hsinchu 30013, Taiwan
| | - Kuen-Jer Tsai
- 1] Institute of Clinical Medicine, National Cheng Kung University, 1, University Road, Tainan 701, Taiwan [2] Institute of Basic Medical Science, National Cheng Kung University, 1, University Road, Tainan 701, Taiwan
| | - Yu-Jen Chang
- Genomics Research Center, Academia Sinica, 128, Academia Road, Section 2, Nankang District, Taipei 115, Taiwan
| | - Patricia Kao
- Department of Pathology and Laboratory Medicine, Alzheimer's Disease Center, University of California Davis Medical Center, 2805 50th Street, Sacramento, California 95817, USA
| | - Rima Woods
- Department of Pathology and Laboratory Medicine, Alzheimer's Disease Center, University of California Davis Medical Center, 2805 50th Street, Sacramento, California 95817, USA
| | - Pan-Hsien Kuo
- Institute of Molecular Biology, Academia Sinica, 128, Academia Road, Section 2, Nankang District, Taipei 115, Taiwan
| | - Cheng-Chun Wu
- 1] Institute of Clinical Medicine, National Cheng Kung University, 1, University Road, Tainan 701, Taiwan [2] Institute of Basic Medical Science, National Cheng Kung University, 1, University Road, Tainan 701, Taiwan
| | - Jhih-Ying Liao
- Institute of Brain Science, School of Medicine, National Yang Ming University, 155, Linong Street, Section 2, Taipei 112, Taiwan
| | - Shih-Chieh Chou
- 1] Genomics Research Center, Academia Sinica, 128, Academia Road, Section 2, Nankang District, Taipei 115, Taiwan [2] Institute of Microbiology and Immunology, School of Life Sciences, National Yang Ming University, 155, Linong Street, Section 2, Taipei 112, Taiwan
| | - Vinson Lin
- Department of Chemistry, National Taiwan University, 1, Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Lee-Way Jin
- Department of Pathology and Laboratory Medicine, Alzheimer's Disease Center, University of California Davis Medical Center, 2805 50th Street, Sacramento, California 95817, USA
| | - Hanna S Yuan
- Institute of Molecular Biology, Academia Sinica, 128, Academia Road, Section 2, Nankang District, Taipei 115, Taiwan
| | - Irene H Cheng
- Institute of Brain Science, School of Medicine, National Yang Ming University, 155, Linong Street, Section 2, Taipei 112, Taiwan
| | - Pang-Hsien Tu
- Institute of Biomedical Sciences, Academia Sinica, 128, Academia Road, Section 2, Nankang District, Taipei 115, Taiwan
| | - Yun-Ru Chen
- 1] Genomics Research Center, Academia Sinica, 128, Academia Road, Section 2, Nankang District, Taipei 115, Taiwan [2] Institute of Bioinformatics and Structural Biology, National Tsing Hua University, 101, Kuang fu Road, Section 2, Hsinchu 30013, Taiwan
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179
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Zheng M, Shi Y, Fan D. Nuclear TAR DNA-binding protein 43: A new target for amyotrophic lateral sclerosis treatment. Neural Regen Res 2014; 8:3284-95. [PMID: 25206650 PMCID: PMC4145946 DOI: 10.3969/j.issn.1673-5374.2013.35.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Abnormal TAR DNA-binding protein 43 (TDP-43) inclusion bodies can be detected in the degenerative neurons of amyotrophic lateral sclerosis. In this study, we induced chronic oxidative stress injury by applying malonate to cultured mouse cortical motor neurons. In the later stages of the malonate insult, TDP-43 expression reduced in the nuclei and transferred to the cytoplasm. This was accompanied by neuronal death, mimicking the pathological changes in TDP-43 that are seen in patients with amyotrophic lateral sclerosis. Interestingly, in the early stages of the response to malonate treatment, nuclear TDP-43 expression increased, and neurons remained relatively intact, without inclusion bodies or fragmentation. Therefore, we hypothesized that the increase of nuclear TDP-43 expression might be a pro-survival factor against oxidative stress injury. This hypothesis was confirmed by an in vitro transgenic experiment, in which overexpression of wild type mouse TDP-43 in cultured cortical motor neurons significantly reduced malonate-induced neuronal death. Our findings suggest that the loss of function of TDP-43 is an important cause of neuronal degeneration, and upregulation of nuclear TDP-43 expression might be neuroprotective in amyotrophic lateral sclerosis.
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Affiliation(s)
- Mei Zheng
- Department of Neurology, Peking University Third Hospital, Beijing 100191, China
| | - Yujie Shi
- School of Pharmaceutical Sciences, Peking University, Beijing 100083, China
| | - Dongsheng Fan
- Department of Neurology, Peking University Third Hospital, Beijing 100191, China
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180
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Abstract
Saccharomyces cerevisiae (baker's yeast) is a well-established eukaryotic model organism, which has significantly contributed to our understanding of mechanisms that drive numerous core cellular processes in higher eukaryotes. Moreover, this has led to a greater understanding of the underlying pathobiology associated with disease in humans. This tractable model offers an abundance of analytical capabilities, including a vast array of global genetics and molecular resources that allow genome-wide screening to be carried out relatively simply and cheaply. A prime example of the versatility and potential for applying yeast technologies to explore a mammalian disease is in the development of yeast models for amyloid diseases such as Alzheimer's, Parkinson's and Huntington's. The present chapter provides a broad overview of high profile human neurodegenerative diseases that have been modelled in yeast. We focus on some of the most recent findings that have been developed through genetic and drug screening studies using yeast genomic resources. Although this relatively simple unicellular eukaryote seems far removed from relatively complex multicellular organisms such as mammals, the conserved mechanisms for how amyloid exhibits toxicity clearly underscore the value of carrying out such studies in yeast.
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181
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Yamashita M, Nonaka T, Hirai S, Miwa A, Okado H, Arai T, Hosokawa M, Akiyama H, Hasegawa M. Distinct pathways leading to TDP-43-induced cellular dysfunctions. Hum Mol Genet 2014; 23:4345-56. [PMID: 24698978 DOI: 10.1093/hmg/ddu152] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
TAR DNA-binding protein of 43 kDa (TDP-43) is the major component protein of inclusions found in brains of patients with amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD-TDP). However, the molecular mechanisms by which TDP-43 causes neuronal dysfunction and death remain unknown. Here, we report distinct cytotoxic effects of full-length TDP-43 (FL-TDP) and its C-terminal fragment (CTF) in SH-SY5Y cells. When FL-TDP was overexpressed in the cells using a lentiviral system, exogenous TDP-43, like endogenous TDP-43, was expressed mainly in nuclei of cells without any intracellular inclusions. However, these cells showed striking cell death, caspase activation and growth arrest at G2/M phase, indicating that even simple overexpression of TDP-43 induces cellular dysfunctions leading to apoptosis. On the other hand, cells expressing TDP-43 CTF showed cytoplasmic aggregates but without significant cell death, compared with cells expressing FL-TDP. Confocal microscopic analyses revealed that RNA polymerase II (RNA pol II) and several transcription factors, such as specificity protein 1 and cAMP-response-element-binding protein, were co-localized with the aggregates of TDP-43 CTF, suggesting that sequestration of these factors into TDP-43 aggregates caused transcriptional dysregulation. Indeed, accumulation of RNA pol II at TDP-43 inclusions was detected in brains of patients with FTLD-TDP. Furthermore, apoptosis was not observed in affected neurons of FTLD-TDP brains containing phosphorylated and aggregated TDP-43 pathology. Our results suggest that different pathways of TDP-43-induced cellular dysfunction may contribute to the degeneration cascades involved in the onset of ALS and FTLD-TDP.
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Affiliation(s)
| | | | - Shinobu Hirai
- Department of Brain Development and Neural Regeneration and
| | - Akiko Miwa
- Department of Brain Development and Neural Regeneration and
| | - Haruo Okado
- Department of Brain Development and Neural Regeneration and
| | - Tetsuaki Arai
- Department of Neuropsychiatry, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Masato Hosokawa
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Haruhiko Akiyama
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
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182
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Budini M, Romano V, Quadri Z, Buratti E, Baralle FE. TDP-43 loss of cellular function through aggregation requires additional structural determinants beyond its C-terminal Q/N prion-like domain. Hum Mol Genet 2014; 24:9-20. [PMID: 25122661 PMCID: PMC4262490 DOI: 10.1093/hmg/ddu415] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
TDP-43 aggregates are the neurohistological landmark of diseases like amyotrophic lateral sclerosis and frontotemporal dementia. Their role in the pathogenesis of these conditions is not yet clear mainly due to the lack of proper models of aggregation that may allow the study of the mechanism of formation, their interactions with other cellular components and their effect on the cell metabolism. In this work, we have used tandem repeats of the prion like Q/N-rich region of TAR DNA-binding protein (TDP-43) fused to additional TDP-43 protein sequences to trigger aggregate formation in neuronal and non-neuronal cell lines. At the functional level, these aggregates are able to sequester endogenous TDP-43 depleting its nuclear levels and inducing loss of function at the pre-mRNA splicing level. No apparent direct cellular toxicity of the aggregates seems to be present beyond the lack of functional TDP-43. To our knowledge, this is the only system that achieves full functional TDP 43 depletion with effects similar to RNAi depletion or gene deletion. As a result, this model will prove useful to investigate the loss-of-function effects mediated by TDP-43 aggregation within cells without affecting the expression of the endogenous gene. We have identified the N-terminus sequence of TDP-43 as the domain that enhances its interaction with the aggregates and its insolubilization. These data show for the first time that cellular TDP-43 aggregation can lead to total loss of function and to defective splicing of TDP-43-dependent splicing events in endogenous genes.
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Affiliation(s)
- Mauricio Budini
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34012 Trieste, Italy
| | - Valentina Romano
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34012 Trieste, Italy
| | - Zainuddin Quadri
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34012 Trieste, Italy
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34012 Trieste, Italy
| | - Francisco E Baralle
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34012 Trieste, Italy
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183
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Pathological stress granules in Alzheimer's disease. Brain Res 2014; 1584:52-8. [PMID: 25108040 DOI: 10.1016/j.brainres.2014.05.052] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/22/2014] [Accepted: 05/02/2014] [Indexed: 02/01/2023]
Abstract
A feature of neurodegenerative disease is the accumulation of insoluble protein aggregates in the brain. In some conditions, including Amyotrophic Lateral Sclerosis and Frontotemporal lobar degeneration, the primary aggregating entities are RNA binding proteins. Through regulated prion-like assembly, RNA binding proteins serve many functions in RNA metabolism that are essential for the healthy maintenance of cells of the central nervous system. Those RNA binding proteins that are the core nucleating factors of stress granules (SGs), including TIA-1, TIAR, TTP and G3BP1, are also found in the pathological lesions of other neurological conditions, such as Alzheimer's disease, where the hallmark aggregating protein is not an RNA binding protein. This discovery suggests that the regulated cellular pathway, which utilizes assembly of RNA binding proteins to package and silence mRNAs during stress, may be integral in the aberrant pathological protein aggregation that occurs in numerous neurodegenerative conditions.
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184
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Profilin 1 associates with stress granules and ALS-linked mutations alter stress granule dynamics. J Neurosci 2014; 34:8083-97. [PMID: 24920614 DOI: 10.1523/jneurosci.0543-14.2014] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mutations in the PFN1 gene encoding profilin 1 are a rare cause of familial amyotrophic lateral sclerosis (ALS). Profilin 1 is a well studied actin-binding protein but how PFN1 mutations cause ALS is unknown. The budding yeast, Saccharomyces cerevisiae, has one PFN1 ortholog. We expressed the ALS-linked profilin 1 mutant proteins in yeast, demonstrating a loss of protein stability and failure to restore growth to profilin mutant cells, without exhibiting gain-of-function toxicity. This model provides for simple and rapid screening of novel ALS-linked PFN1 variants. To gain insight into potential novel roles for profilin 1, we performed an unbiased, genome-wide synthetic lethal screen with yeast cells lacking profilin (pfy1Δ). Unexpectedly, deletion of several stress granule and processing body genes, including pbp1Δ, were found to be synthetic lethal with pfy1Δ. Mutations in ATXN2, the human ortholog of PBP1, are a known ALS genetic risk factor and ataxin 2 is a stress granule component in mammalian cells. Given this genetic interaction and recent evidence linking stress granule dynamics to ALS pathogenesis, we hypothesized that profilin 1 might also associate with stress granules. Here we report that profilin 1 and related protein profilin 2 are novel stress granule-associated proteins in mouse primary cortical neurons and in human cell lines and that ALS-linked mutations in profilin 1 alter stress granule dynamics, providing further evidence for the potential role of stress granules in ALS pathogenesis.
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185
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Song J, Yang Q, Yang J, Larsson L, Hao X, Zhu X, Malmgren-Hill S, Cvijovic M, Fernandez-Rodriguez J, Grantham J, Gustafsson CM, Liu B, Nyström T. Essential genetic interactors of SIR2 required for spatial sequestration and asymmetrical inheritance of protein aggregates. PLoS Genet 2014; 10:e1004539. [PMID: 25079602 PMCID: PMC4117435 DOI: 10.1371/journal.pgen.1004539] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 06/16/2014] [Indexed: 11/19/2022] Open
Abstract
Sir2 is a central regulator of yeast aging and its deficiency increases daughter cell inheritance of stress- and aging-induced misfolded proteins deposited in aggregates and inclusion bodies. Here, by quantifying traits predicted to affect aggregate inheritance in a passive manner, we found that a passive diffusion model cannot explain Sir2-dependent failures in mother-biased segregation of either the small aggregates formed by the misfolded Huntingtin, Htt103Q, disease protein or heat-induced Hsp104-associated aggregates. Instead, we found that the genetic interaction network of SIR2 comprises specific essential genes required for mother-biased segregation including those encoding components of the actin cytoskeleton, the actin-associated myosin V motor protein Myo2, and the actin organization protein calmodulin, Cmd1. Co-staining with Hsp104-GFP demonstrated that misfolded Htt103Q is sequestered into small aggregates, akin to stress foci formed upon heat stress, that fail to coalesce into inclusion bodies. Importantly, these Htt103Q foci, as well as the ATPase-defective Hsp104Y662A-associated structures previously shown to be stable stress foci, co-localized with Cmd1 and Myo2-enriched structures and super-resolution 3-D microscopy demonstrated that they are associated with actin cables. Moreover, we found that Hsp42 is required for formation of heat-induced Hsp104Y662A foci but not Htt103Q foci suggesting that the routes employed for foci formation are not identical. In addition to genes involved in actin-dependent processes, SIR2-interactors required for asymmetrical inheritance of Htt103Q and heat-induced aggregates encode essential sec genes involved in ER-to-Golgi trafficking/ER homeostasis.
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Affiliation(s)
- Jia Song
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Qian Yang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Junsheng Yang
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Lisa Larsson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Xinxin Hao
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Xuefeng Zhu
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Göteborg, Sweden
| | - Sandra Malmgren-Hill
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Marija Cvijovic
- Mathematical Sciences, University of Gothenburg, Gothenburg, Sweden
- Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | | | - Julie Grantham
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Claes M. Gustafsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Göteborg, Sweden
| | - Beidong Liu
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
- * E-mail:
| | - Thomas Nyström
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
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186
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Jackrel ME, Shorter J. Potentiated Hsp104 variants suppress toxicity of diverse neurodegenerative disease-linked proteins. Dis Model Mech 2014; 7:1175-84. [PMID: 25062688 PMCID: PMC4174528 DOI: 10.1242/dmm.016113] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Protein misfolding is implicated in numerous lethal neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and Parkinson disease (PD). There are no therapies that reverse these protein-misfolding events. We aim to apply Hsp104, a hexameric AAA+ protein from yeast, to target misfolded conformers for reactivation. Hsp104 solubilizes disordered aggregates and amyloid, but has limited activity against human neurodegenerative disease proteins. Thus, we have previously engineered potentiated Hsp104 variants that suppress aggregation, proteotoxicity and restore proper protein localization of ALS and PD proteins in Saccharomyces cerevisiae, and mitigate neurodegeneration in an animal PD model. Here, we establish that potentiated Hsp104 variants possess broad substrate specificity and, in yeast, suppress toxicity and aggregation induced by wild-type TDP-43, FUS and α-synuclein, as well as missense mutant versions of these proteins that cause neurodegenerative disease. Potentiated Hsp104 variants also rescue toxicity and aggregation of TAF15 but not EWSR1, two RNA-binding proteins with a prion-like domain that are connected with the development of ALS and frontotemporal dementia. Thus, potentiated Hsp104 variants are not entirely non-specific. Indeed, they do not unfold just any natively folded protein. Rather, potentiated Hsp104 variants are finely tuned to unfold proteins bearing short unstructured tracts that are not recognized by wild-type Hsp104. Our studies establish the broad utility of potentiated Hsp104 variants.
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Affiliation(s)
- Meredith E Jackrel
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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187
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Huang CC, Bose JK, Majumder P, Lee KH, Huang JTJ, Huang JK, Shen CKJ. Metabolism and mis-metabolism of the neuropathological signature protein TDP-43. J Cell Sci 2014; 127:3024-38. [PMID: 24860144 DOI: 10.1242/jcs.136150] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
TDP-43 (also known as TARDBP) is a pathological signature protein of neurodegenerative diseases, with TDP-43 proteinopathies including frontotemporal lobar degeneration (FTLD)-TDP and amyotrophic lateral sclerosis (ALS)-TDP. These TDP-43 proteinopathies are characterized by cytoplasmic insoluble TDP-43-positive aggregates in the diseased cells, the formation of which requires the seeding of TDP-25 fragment generated by caspase cleavage of TDP-43. We have investigated the metabolism and mis-metabolism of TDP-43 in cultured cells and found that endogenous and exogenously overexpressed TDP-43 is degraded not only by the ubiquitin proteasome system (UPS) and macroautophagy, but also by the chaperone-mediated autophagy (CMA) mediated through an interaction between Hsc70 (also known as HSPA8) and ubiquitylated TDP-43. Furthermore, proteolytic cleavage of TDP-43 by caspase(s) is a necessary intermediate step for degradation of the majority of the TDP-43 protein, with the TDP-25 and TDP-35 fragments being the main substrates. Finally, we have determined the threshold level of the TDP-25 fragment that is necessary for formation of the cytosolic TDP-43-positive aggregates in cells containing the full-length TDP-43 at an elevated level close to that found in patients with TDP-43 proteinopathies. A comprehensive model of the metabolism and mis-metabolism of TDP-43 in relation to these findings is presented.
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Affiliation(s)
- Chi-Chen Huang
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology/Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, Taiwan
| | | | - Pritha Majumder
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan
| | - Kuen-Haur Lee
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | | | - Jeffrey K Huang
- Department of Biology, Georgetown University, Washington, DC 20057, USA
| | - Che-Kun James Shen
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology/Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, Taiwan
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188
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Jackrel ME, DeSantis ME, Martinez BA, Castellano LM, Stewart RM, Caldwell KA, Caldwell GA, Shorter J. Potentiated Hsp104 variants antagonize diverse proteotoxic misfolding events. Cell 2014; 156:170-82. [PMID: 24439375 DOI: 10.1016/j.cell.2013.11.047] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 09/28/2013] [Accepted: 11/20/2013] [Indexed: 11/16/2022]
Abstract
There are no therapies that reverse the proteotoxic misfolding events that underpin fatal neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). Hsp104, a conserved hexameric AAA+ protein from yeast, solubilizes disordered aggregates and amyloid but has no metazoan homolog and only limited activity against human neurodegenerative disease proteins. Here, we reprogram Hsp104 to rescue TDP-43, FUS, and α-synuclein proteotoxicity by mutating single residues in helix 1, 2, or 3 of the middle domain or the small domain of nucleotide-binding domain 1. Potentiated Hsp104 variants enhance aggregate dissolution, restore proper protein localization, suppress proteotoxicity, and in a C. elegans PD model attenuate dopaminergic neurodegeneration. Potentiating mutations reconfigure how Hsp104 subunits collaborate, desensitize Hsp104 to inhibition, obviate any requirement for Hsp70, and enhance ATPase, translocation, and unfoldase activity. Our work establishes that disease-associated aggregates and amyloid are tractable targets and that enhanced disaggregases can restore proteostasis and mitigate neurodegeneration.
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Affiliation(s)
- Meredith E Jackrel
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Morgan E DeSantis
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bryan A Martinez
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Laura M Castellano
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Pharmacology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rachel M Stewart
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kim A Caldwell
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Guy A Caldwell
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Pharmacology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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189
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Jackrel ME, Shorter J. Reversing deleterious protein aggregation with re-engineered protein disaggregases. Cell Cycle 2014; 13:1379-83. [PMID: 24694655 DOI: 10.4161/cc.28709] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Aberrant protein folding is severely problematic and manifests in numerous disorders, including amyotrophic lateral sclerosis (ALS), Parkinson disease (PD), Huntington disease (HD), and Alzheimer disease (AD). Patients with each of these disorders are characterized by the accumulation of mislocalized protein deposits. Treatments for these disorders remain palliative, and no available therapeutics eliminate the underlying toxic conformers. An intriguing approach to reverse deleterious protein misfolding is to upregulate chaperones to restore proteostasis. We recently reported our work to re-engineer a prion disaggregase from yeast, Hsp104, to reverse protein misfolding implicated in human disease. These potentiated Hsp104 variants suppress TDP-43, FUS, and α-synuclein toxicity in yeast, eliminate aggregates, reverse cellular mislocalization, and suppress dopaminergic neurodegeneration in an animal model of PD. Here, we discuss this work and its context, as well as approaches for further developing potentiated Hsp104 variants for application in reversing protein-misfolding disorders.
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Affiliation(s)
- Meredith E Jackrel
- Department of Biochemistry and Biophysics; Perelman School of Medicine at the University of Pennsylvania; Philadelphia, PA USA
| | - James Shorter
- Department of Biochemistry and Biophysics; Perelman School of Medicine at the University of Pennsylvania; Philadelphia, PA USA
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190
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Interaction of transactive response DNA binding protein 43 with nuclear factor κB in mild cognitive impairment with episodic memory deficits. Acta Neuropathol Commun 2014; 2:37. [PMID: 24690380 PMCID: PMC4230634 DOI: 10.1186/2051-5960-2-37] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 03/20/2014] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Transactive response DNA binding protein 43 (TDP-43) is detected in pathological inclusions in many cases of Alzheimer's disease (AD) and mild cognitive impairment (MCI), but its pathological role in AD and MCI remains unknown. Recently, TDP-43 was reported to contribute to pathogenesis in amyotrophic lateral sclerosis through its interaction with p65 nuclear factor κB (NF-κB) resulting in abnormal hyperactivation of this signaling pathway in motor neurons. Hence, we investigated the interaction of TDP-43 with p65 in the temporal cortex of subjects with a clinical diagnosis of MCI (n = 12) or AD (n = 12) as well as of age-matched controls with no cognitive impairment (NCI, n = 12). RESULTS Immunoprecipitation and immunofluorescence approaches revealed a robust interaction of TDP-43 with p65 in the nucleus of temporal lobe neurons in four individuals with MCI (named MCI-p). These MCI-p cases exhibited high expression levels of soluble TDP-43, p65, phosphorylated p65 and low expression levels of β-amyloid 40 when compared to AD or NCI cases. The analysis of cognitive performance tests showed that MCI-p individuals presented intermediate deficits of global cognition and episodic memory between those of AD cases and of NCI cases and MCI cases with no interaction of TDP-43 with p65. CONCLUSIONS From these results, we propose that enhanced NF-κB activation due to TDP-43 and p65 interaction may contribute to neuronal dysfunction in MCI individuals with episodic memory deficits. Accordingly, treatment with inhibitors of NF-κB activation may be considered for MCI individuals with episodic memory deficits.
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191
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Disease causing mutants of TDP-43 nucleic acid binding domains are resistant to aggregation and have increased stability and half-life. Proc Natl Acad Sci U S A 2014; 111:4309-14. [PMID: 24591609 DOI: 10.1073/pnas.1317317111] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Over the last two decades many secrets of the age-related human neural proteinopathies have been revealed. A common feature of these diseases is abnormal, and possibly pathogenic, aggregation of specific proteins in the effected tissue often resulting from inherent or decreased structural stability. An archetype example of this is superoxide dismutase-1, the first genetic factor to be linked with amyotrophic lateral sclerosis (ALS). Mutant or posttranslationally modified TAR DNA binding protein-32 (TDP-43) is also strongly associated with ALS and an increasingly large number of other neurodegenerative diseases, including frontotemporal lobar degeneration (FTLD). Cytoplasmic mislocalization and elevated half-life is a characteristic of mutant TDP-43. Furthermore, patient age at the onset of disease symptoms shows a good inverse correlation with mutant TDP-43 half-life. Here we show that ALS and FTLD-associated TDP-43 mutations in the central nucleic acid binding domains lead to elevated half-life and this is commensurate with increased thermal stability and inhibition of aggregation. It is achieved without impact on secondary, tertiary, or quaternary structure. We propose that tighter structural cohesion contributes to reduced protein turnover, increasingly abnormal proteostasis and, ultimately, faster onset of disease symptoms. These results contrast our perception of neurodegenerative diseases as misfolded proteinopathies and delineate a novel path from the molecular characteristics of mutant TDP-43 to aberrant cellular effects and patient phenotype.
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192
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Mackness BC, Tran MT, McClain SP, Matthews CR, Zitzewitz JA. Folding of the RNA recognition motif (RRM) domains of the amyotrophic lateral sclerosis (ALS)-linked protein TDP-43 reveals an intermediate state. J Biol Chem 2014; 289:8264-76. [PMID: 24497641 DOI: 10.1074/jbc.m113.542779] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Pathological alteration of TDP-43 (TAR DNA-binding protein-43), a protein involved in various RNA-mediated processes, is a hallmark feature of the neurodegenerative diseases amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Fragments of TDP-43, composed of the second RNA recognition motif (RRM2) and the disordered C terminus, have been observed in cytoplasmic inclusions in sporadic amyotrophic lateral sclerosis cases, suggesting that conformational changes involving RRM2 together with the disordered C terminus play a role in aggregation and toxicity. The biophysical data collected by CD and fluorescence spectroscopies reveal a three-state equilibrium unfolding model for RRM2, with a partially folded intermediate state that is not observed in RRM1. Strikingly, a portion of RRM2 beginning at position 208, which mimics a cleavage site observed in patient tissues, increases the population of this intermediate state. Mutually stabilizing interactions between the domains in the tethered RRM1 and RRM2 construct reduce the population of the intermediate state and enhance DNA/RNA binding. Despite the high sequence homology of the two domains, a network of large hydrophobic residues in RRM2 provides a possible explanation for the increased stability of RRM2 compared with RRM1. The cluster analysis suggests that the intermediate state may play a functional role by enhancing access to the nuclear export signal contained within its sequence. The intermediate state may also serve as a molecular hazard linking productive folding and function with pathological misfolding and aggregation that may contribute to disease.
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Affiliation(s)
- Brian C Mackness
- From the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
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193
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Kim HJ, Raphael AR, LaDow ES, McGurk L, Weber RA, Trojanowski JQ, Lee VMY, Finkbeiner S, Gitler AD, Bonini NM. Therapeutic modulation of eIF2α phosphorylation rescues TDP-43 toxicity in amyotrophic lateral sclerosis disease models. Nat Genet 2014; 46:152-60. [PMID: 24336168 PMCID: PMC3934366 DOI: 10.1038/ng.2853] [Citation(s) in RCA: 288] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 11/22/2013] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, late-onset neurodegenerative disease primarily affecting motor neurons. A unifying feature of many proteins associated with ALS, including TDP-43 and ataxin-2, is that they localize to stress granules. Unexpectedly, we found that genes that modulate stress granules are strong modifiers of TDP-43 toxicity in Saccharomyces cerevisiae and Drosophila melanogaster. eIF2α phosphorylation is upregulated by TDP-43 toxicity in flies, and TDP-43 interacts with a central stress granule component, polyA-binding protein (PABP). In human ALS spinal cord neurons, PABP accumulates abnormally, suggesting that prolonged stress granule dysfunction may contribute to pathogenesis. We investigated the efficacy of a small molecule inhibitor of eIF2α phosphorylation in ALS models. Treatment with this inhibitor mitigated TDP-43 toxicity in flies and mammalian neurons. These findings indicate that the dysfunction induced by prolonged stress granule formation might contribute directly to ALS and that compounds that mitigate this process may represent a novel therapeutic approach.
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Affiliation(s)
- Hyung-Jun Kim
- 1] Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA. [2]
| | - Alya R Raphael
- Department of Genetics, Stanford University School of Medicine, Stanford, California, USA
| | - Eva S LaDow
- Gladstone Institute of Neurological Disease, San Francisco, California, USA
| | - Leeanne McGurk
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ross A Weber
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John Q Trojanowski
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Virginia M-Y Lee
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Steven Finkbeiner
- Gladstone Institute of Neurological Disease, San Francisco, California, USA
| | - Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, California, USA
| | - Nancy M Bonini
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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194
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De Marco G, Lomartire A, Mandili G, Lupino E, Buccinnà B, Ramondetti C, Moglia C, Novelli F, Piccinini M, Mostert M, Rinaudo MT, Chiò A, Calvo A. Reduced cellular Ca(2+) availability enhances TDP-43 cleavage by apoptotic caspases. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:725-34. [PMID: 24440855 DOI: 10.1016/j.bbamcr.2014.01.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 12/20/2013] [Accepted: 01/08/2014] [Indexed: 12/13/2022]
Abstract
Accumulation of transactive response DNA binding protein (TDP-43) fragments in motor neurons is a post mortem hallmark of different neurodegenerative diseases. TDP-43 fragments are the products of the apoptotic caspases-3 and -7. Either excessive or insufficient cellular Ca(2+) availability is associated with activation of apoptotic caspases. However, as far as we know, it is not described whether activation of caspases, due to restricted intracellular Ca(2+), affects TDP-43 cleavage. Here we show that in various cell lineages with restricted Ca(2+) availability, TDP-43 is initially cleaved by caspases-3 and -7 and then, also by caspases-6 and -8 once activated by caspase-3. Furthermore, we disclose the existence of a TDP-43 caspase-mediated fragment of 15kDa, in addition to the well-known fragments of 35 and 25kDa. Interestingly, with respect to the other two fragments this novel fragment is the major product of caspase activity on murine TDP-43 whereas in human cell lines the opposite occurs. This outcome should be considered when murine models are used to investigate TDP-43 proteinopathies.
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Affiliation(s)
- Giovanni De Marco
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy; Department of Oncology, University of Turin, Turin, Italy
| | - Annarosa Lomartire
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy; Department of Oncology, University of Turin, Turin, Italy
| | - Giorgia Mandili
- Center for Experimental Research and Medical Studies (CeRMS), University of Turin, Turin, Italy; Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy
| | - Elisa Lupino
- Department of Oncology, University of Turin, Turin, Italy
| | | | | | - Cristina Moglia
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy; CRESLA Turin, AOU Città della Salute e della Scienza, Turin, Italy
| | - Francesco Novelli
- Center for Experimental Research and Medical Studies (CeRMS), University of Turin, Turin, Italy; Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy
| | | | - Michael Mostert
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | | | - Adriano Chiò
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy; CRESLA Turin, AOU Città della Salute e della Scienza, Turin, Italy
| | - Andrea Calvo
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy; CRESLA Turin, AOU Città della Salute e della Scienza, Turin, Italy
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195
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Yeast prions and human prion-like proteins: sequence features and prediction methods. Cell Mol Life Sci 2014; 71:2047-63. [PMID: 24390581 DOI: 10.1007/s00018-013-1543-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/12/2013] [Accepted: 12/16/2013] [Indexed: 11/27/2022]
Abstract
Prions are self-propagating infectious protein isoforms. A growing number of prions have been identified in yeast, each resulting from the conversion of soluble proteins into an insoluble amyloid form. These yeast prions have served as a powerful model system for studying the causes and consequences of prion aggregation. Remarkably, a number of human proteins containing prion-like domains, defined as domains with compositional similarity to yeast prion domains, have recently been linked to various human degenerative diseases, including amyotrophic lateral sclerosis. This suggests that the lessons learned from yeast prions may help in understanding these human diseases. In this review, we examine what has been learned about the amino acid sequence basis for prion aggregation in yeast, and how this information has been used to develop methods to predict aggregation propensity. We then discuss how this information is being applied to understand human disease, and the challenges involved in applying yeast prediction methods to higher organisms.
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196
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Turner MR, Bowser R, Bruijn L, Dupuis L, Ludolph A, McGrath M, Manfredi G, Maragakis N, Miller RG, Pullman SL, Rutkove SB, Shaw PJ, Shefner J, Fischbeck KH. Mechanisms, models and biomarkers in amyotrophic lateral sclerosis. Amyotroph Lateral Scler Frontotemporal Degener 2013; 14 Suppl 1:19-32. [PMID: 23678877 DOI: 10.3109/21678421.2013.778554] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The last 30 years have seen a major advance in the understanding of the clinical and pathological heterogeneity of amyotrophic lateral sclerosis (ALS), and its overlap with frontotemporal dementia. Multiple, seemingly disparate biochemical pathways converge on a common clinical syndrome characterized by progressive loss of upper and lower motor neurons. Pathogenic themes in ALS include excitotoxicity, oxidative stress, mitochondrial dysfunction, neuroinflammation, altered energy metabolism, and most recently RNA mis-processing. The transgenic rodent, overexpressing mutant superoxide dismutase-1, is now only one of several models of ALS pathogenesis. The nematode, fruit fly and zebrafish all offer fresh insight, and the development of induced pluripotent stem cell-derived motor neurons holds promise for the screening of candidate therapeutics. The lack of useful biomarkers in ALS contributes to diagnostic delay, and the inability to stratify patients by prognosis may be an important factor in the failure of therapeutic trials. Biomarkers sensitive to disease activity might lessen reliance on clinical measures and survival as trial endpoints and reduce study length. Emerging proteomic markers of neuronal loss and glial activity in cerebrospinal fluid, a cortical signature derived from advanced structural and functional MRI, and the development of more sensitive measurements of lower motor neuron physiology are leading a new phase of biomarker-driven therapeutic discovery.
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Affiliation(s)
- Martin R Turner
- Nuffield Department of Clinical Neurosciences, University of Oxford, UK.
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197
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Janssens J, Van Broeckhoven C. Pathological mechanisms underlying TDP-43 driven neurodegeneration in FTLD-ALS spectrum disorders. Hum Mol Genet 2013; 22:R77-87. [PMID: 23900071 PMCID: PMC3782069 DOI: 10.1093/hmg/ddt349] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 07/07/2013] [Accepted: 07/21/2013] [Indexed: 01/09/2023] Open
Abstract
Aggregation of misfolded TAR DNA-binding protein 43 (TDP-43) is a striking hallmark of neurodegenerative processes that are observed in several neurological disorders, and in particular in most patients diagnosed with frontotemporal lobar degeneration (FTLD) or amyotrophic lateral sclerosis (ALS). A direct causal link with TDP-43 brain proteinopathy was provided by the identification of pathogenic mutations in TARDBP, the gene encoding TDP-43, in ALS families. However, TDP-43 proteinopathy has also been observed in carriers of mutations in several other genes associated with both ALS and FTLD demonstrating a key role for TDP-43 in neurodegeneration. To date, and despite substantial research into the biology of TDP-43, its functioning in normal brain and in neurodegeneration processes remains largely elusive. Nonetheless, breakthroughs using cellular and animal models have provided valuable insights into ALS and FTLD pathogenesis. Accumulating evidence has redirected the research focus towards a major role for impaired RNA metabolism and protein homeostasis. At the same time, the concept that toxic TDP-43 protein aggregates promote neurodegeneration is losing its credibility. This review aims at highlighting and discussing the current knowledge on TDP-43 driven pathomechanisms leading to neurodegeneration as observed in TDP-43 proteinopathies. Based on the complexity of the associated neurological diseases, a clear understanding of the essential pathological modifications will be crucial for further therapeutic interventions.
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Affiliation(s)
- Jonathan Janssens
- Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, VIB, Antwerp, Belgium
- Laboratory of Neurogenetics Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Christine Van Broeckhoven
- Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, VIB, Antwerp, Belgium
- Laboratory of Neurogenetics Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
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198
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Liu R, Yang G, Nonaka T, Arai T, Jia W, Cynader MS. Reducing TDP-43 aggregation does not prevent its cytotoxicity. Acta Neuropathol Commun 2013; 1:49. [PMID: 24252504 PMCID: PMC3893365 DOI: 10.1186/2051-5960-1-49] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 08/02/2013] [Indexed: 01/15/2023] Open
Abstract
Background TAR DNA-binding protein 43 (TDP-43) is a protein that is involved in the pathology of Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD). In patients with these neurodegenerative diseases, TDP-43 does not remain in its normal nuclear location, but instead forms insoluble aggregates in both the nucleus and cytoplasm of affected neurons. Results We used high density peptide array analysis to identify regions in TDP-43 that are bound by TDP-43 itself and designed candidate peptides that might be able to reduce TDP-43 aggregation. We found that two of the synthetic peptides identified with this approach could effectively inhibit the formation of TDP-43 protein aggregates in a concentration-dependent manner in HeLa cells in which a mutated human TDP-43 gene was overexpressed. However, despite reducing aggregation, these peptides did not reduce or prevent cell death. Similar results were observed in HeLa cells treated with arsenite. Again we found reduced aggregation, in this case of wild type TDP-43, but no difference in cell death. Conclusions Our results suggest that TDP-43 aggregation is associated with the cell death process rather than being a direct cause.
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199
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Steele JW, Ju S, Lachenmayer ML, Liken J, Stock A, Kim SH, Delgado LM, Alfaro IE, Bernales S, Verdile G, Bharadwaj P, Gupta V, Barr R, Friss A, Dolios G, Wang R, Ringe D, Protter AA, Martins RN, Ehrlich ME, Yue Z, Petsko GA, Gandy S. Latrepirdine stimulates autophagy and reduces accumulation of α-synuclein in cells and in mouse brain. Mol Psychiatry 2013; 18:882-8. [PMID: 22869031 PMCID: PMC3523214 DOI: 10.1038/mp.2012.115] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 06/04/2012] [Accepted: 06/12/2012] [Indexed: 11/29/2022]
Abstract
Latrepirdine (Dimebon; dimebolin) is a neuroactive compound that was associated with enhanced cognition, neuroprotection and neurogenesis in laboratory animals, and has entered phase II clinical trials for both Alzheimer's disease and Huntington's disease (HD). Based on recent indications that latrepirdine protects cells against cytotoxicity associated with expression of aggregatable neurodegeneration-related proteins, including Aβ42 and γ-synuclein, we sought to determine whether latrepirdine offers protection to Saccharomyces cerevisiae. We utilized separate and parallel expression in yeast of several neurodegeneration-related proteins, including α-synuclein (α-syn), the amyotrophic lateral sclerosis-associated genes TDP43 and FUS, and the HD-associated protein huntingtin with a 103 copy-polyglutamine expansion (HTT gene; htt-103Q). Latrepirdine effects on α-syn clearance and toxicity were also measured following treatment of SH-SY5Y cells or chronic treatment of wild-type mice. Latrepirdine only protected yeast against the cytotoxicity associated with α-syn, and this appeared to occur via induction of autophagy. We further report that latrepirdine stimulated the degradation of α-syn in differentiated SH-SY5Y neurons, and in mouse brain following chronic administration, in parallel with elevation of the levels of markers of autophagic activity. Ongoing experiments will determine the utility of latrepirdine to abrogate α-syn accumulation in transgenic mouse models of α-syn neuropathology. We propose that latrepirdine may represent a novel scaffold for discovery of robust pro-autophagic/anti-neurodegeneration compounds, which might yield clinical benefit for synucleinopathies including Parkinson's disease, Lewy body dementia, rapid eye movement (REM) sleep disorder and/or multiple system atrophy, following optimization of its pro-autophagic and pro-neurogenic activities.
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Affiliation(s)
- John W. Steele
- Department of Neurology, Mount Sinai School of Medicine, New York NY 10029,Department of Psychiatry and Mount Sinai Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York NY 10029,Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York NY 10065
| | - Shulin Ju
- Department of Biochemistry and Chemistry, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham MA 02453
| | - M. Lenard Lachenmayer
- Department of Neurology, Mount Sinai School of Medicine, New York NY 10029,Department of Neurology, University of Bonn, Bonn, Germany
| | - Jessica Liken
- Department of Biochemistry and Chemistry, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham MA 02453
| | - Aryeh Stock
- Department of Neurology, Mount Sinai School of Medicine, New York NY 10029,Department of Psychiatry and Mount Sinai Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York NY 10029
| | - Soong Ho Kim
- Department of Neurology, Mount Sinai School of Medicine, New York NY 10029,Department of Psychiatry and Mount Sinai Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York NY 10029
| | | | | | - Sebastian Bernales
- Fundación Ciencia Para La Vida, Santiago, Chile,Medivation, Inc., San Francisco, CA 94105 USA
| | - Giuseppe Verdile
- Centre of Excellence for Alzheimer’s Disease Research & Care, School of Medical Sciences, Edith Cowan University, Western Australia, Australia, 6027
| | - Prashant Bharadwaj
- Centre of Excellence for Alzheimer’s Disease Research & Care, School of Medical Sciences, Edith Cowan University, Western Australia, Australia, 6027
| | - Veer Gupta
- Centre of Excellence for Alzheimer’s Disease Research & Care, School of Medical Sciences, Edith Cowan University, Western Australia, Australia, 6027
| | - Renae Barr
- Centre of Excellence for Alzheimer’s Disease Research & Care, School of Medical Sciences, Edith Cowan University, Western Australia, Australia, 6027
| | - Amy Friss
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York NY 10029
| | - Georgia Dolios
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York NY 10029
| | - Rong Wang
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York NY 10029
| | - Dagmar Ringe
- Department of Biochemistry and Chemistry, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham MA 02453
| | | | - Ralph N. Martins
- Centre of Excellence for Alzheimer’s Disease Research & Care, School of Medical Sciences, Edith Cowan University, Western Australia, Australia, 6027,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, WA, Australia,Sir James McCusker Alzheimer’s Disease Research Unit, Hollywood Private Hospital, Nedlands, WA, Australia
| | - Michelle E. Ehrlich
- Department of Neurology, Mount Sinai School of Medicine, New York NY 10029,Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York NY 10029,Department of Pediatrics, Mount Sinai School of Medicine, New York NY 10029
| | - Zhenyu Yue
- Department of Neurology, Mount Sinai School of Medicine, New York NY 10029,Department of Neuroscience, Mount Sinai School of Medicine, New York NY 10029
| | - Gregory A. Petsko
- Department of Biochemistry and Chemistry, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham MA 02453
| | - Sam Gandy
- Department of Neurology, Mount Sinai School of Medicine, New York NY 10029,Department of Psychiatry and Mount Sinai Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York NY 10029,James J Peters VA Medical Center, Bronx NY 10468,To whom correspondence should be addressed: Sam Gandy, M.D., Ph.D., Departments of Neurology and Psychiatry, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1137, New York, NY 10029 USA or
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Gendron TF, Rademakers R, Petrucelli L. TARDBP mutation analysis in TDP-43 proteinopathies and deciphering the toxicity of mutant TDP-43. J Alzheimers Dis 2013; 33 Suppl 1:S35-45. [PMID: 22751173 DOI: 10.3233/jad-2012-129036] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The identification of TAR DNA-binding protein 43 (TDP-43) as the major disease protein in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin inclusions has defined a new class of neurodegenerative conditions: the TDP-43 proteinopathies. This breakthrough was quickly followed by mutation analysis of TARDBP, the gene encoding TDP-43. Herein, we provide a review of our previously published efforts that led to the identification of 3 TARDBP mutations (p.M337V, p.N345K, and p.I383V) in familial ALS patients, two of which were novel. With over 40 TARDBP mutations now discovered, there exists conclusive evidence that TDP-43 plays a direct role in neurodegeneration. The onus is now on researchers to elucidate the mechanisms by which mutant TDP-43 confers toxicity, and to exploit these findings to gain a better understanding of how TDP-43 contributes to the pathogenesis of disease. Our biochemical analysis of TDP-43 in ALS patient lymphoblastoid cell lines revealed a substantial increase in TDP-43 truncation products, including a ≈ 25 kDa fragment, compared to control lymphoblastoid cell lines. We discuss the putative harmful consequence of abnormal TDP-43 fragmentation, as well as highlight additional mechanisms of toxicity associated with mutant TDP-43.
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Affiliation(s)
- Tania F Gendron
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
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