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Cariulo C, Martufi P, Verani M, Azzollini L, Bruni G, Weiss A, Deguire SM, Lashuel HA, Scaricamazza E, Sancesario GM, Schirinzi T, Mercuri NB, Sancesario G, Caricasole A, Petricca L. Phospho-S129 Alpha-Synuclein Is Present in Human Plasma but Not in Cerebrospinal Fluid as Determined by an Ultrasensitive Immunoassay. Front Neurosci 2019; 13:889. [PMID: 31507364 PMCID: PMC6714598 DOI: 10.3389/fnins.2019.00889] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 08/07/2019] [Indexed: 01/05/2023] Open
Abstract
Accumulation and aggregation of misfolded alpha-synuclein is believed to be a cause of Parkinson’s disease (PD). Phosphorylation of alpha-synuclein at S129 is known to be associated with the pathological misfolding process, but efforts to investigate the relevance of this post-translational modification for pathology have been frustrated by difficulties in detecting and quantifying it in relevant samples. We report novel, ultrasensitive immunoassays based on single-molecule counting technology, useful for detecting alpha-synuclein and its S129 phosphorylated form in clinical samples in the low pg/ml range. Using human CSF and plasma samples, we find levels of alpha-synuclein comparable to those previously reported. However, while alpha-synuclein phosphorylated on S129 could easily be detected in human plasma, where its detection is extremely sensitive to protein phosphatases, its levels in CSF were undetectable, with a possible influence of a matrix effect. In plasma samples from a small test cohort comprising 5 PD individuals and five age-matched control individuals we find that pS129 alpha-synuclein levels are increased in PD plasma samples, in line with previous reports. We conclude that pS129 alpha-synuclein is not detectable in CSF and recommend the addition of phosphatase inhibitors to plasma samples at the time of collection. Moreover, the findings obtained on the small cohort of clinical plasma samples point to plasma pS129 alpha-synuclein levels as a candidate diagnostic biomarker in PD.
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Affiliation(s)
| | - Paola Martufi
- Department of Neuroscience, IRBM S.p.A., Rome, Italy
| | | | | | | | | | - Sean M Deguire
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Eugenia Scaricamazza
- Neurology Unit, Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy
| | | | - Tommaso Schirinzi
- Neurology Unit, Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy
| | - Nicola Biagio Mercuri
- Neurology Unit, Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.,IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Giuseppe Sancesario
- Neurology Unit, Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy
| | | | - Lara Petricca
- Department of Neuroscience, IRBM S.p.A., Rome, Italy
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Daldin M, Fodale V, Cariulo C, Azzollini L, Verani M, Martufi P, Spiezia MC, Deguire SM, Cherubini M, Macdonald D, Weiss A, Bresciani A, Vonsattel JPG, Petricca L, Marsh JL, Gines S, Santimone I, Marano M, Lashuel HA, Squitieri F, Caricasole A. Polyglutamine expansion affects huntingtin conformation in multiple Huntington's disease models. Sci Rep 2017; 7:5070. [PMID: 28698602 PMCID: PMC5505970 DOI: 10.1038/s41598-017-05336-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 06/14/2017] [Indexed: 12/29/2022] Open
Abstract
Conformational changes in disease-associated or mutant proteins represent a key pathological aspect of Huntington’s disease (HD) and other protein misfolding diseases. Using immunoassays and biophysical approaches, we and others have recently reported that polyglutamine expansion in purified or recombinantly expressed huntingtin (HTT) proteins affects their conformational properties in a manner dependent on both polyglutamine repeat length and temperature but independent of HTT protein fragment length. These findings are consistent with the HD mutation affecting structural aspects of the amino-terminal region of the protein, and support the concept that modulating mutant HTT conformation might provide novel therapeutic and diagnostic opportunities. We now report that the same conformational TR-FRET based immunoassay detects polyglutamine- and temperature-dependent changes on the endogenously expressed HTT protein in peripheral tissues and post-mortem HD brain tissue, as well as in tissues from HD animal models. We also find that these temperature- and polyglutamine-dependent conformational changes are sensitive to bona-fide phosphorylation on S13 and S16 within the N17 domain of HTT. These findings provide key clinical and preclinical relevance to the conformational immunoassay, and provide supportive evidence for its application in the development of therapeutics aimed at correcting the conformation of polyglutamine-expanded proteins as well as the pharmacodynamics readouts to monitor their efficacy in preclinical models and in HD patients.
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Affiliation(s)
- Manuel Daldin
- IRBM Science Park, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy
| | - Valentina Fodale
- IRBM Science Park, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy.,IRBM Promidis, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy
| | - Cristina Cariulo
- IRBM Science Park, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy
| | - Lucia Azzollini
- IRBM Science Park, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy.,IRBM Promidis, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy
| | - Margherita Verani
- IRBM Science Park, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy.,IRBM Promidis, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy
| | - Paola Martufi
- IRBM Science Park, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy
| | | | - Sean M Deguire
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Station 19, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Marta Cherubini
- Departamento de Ciencias Biomedicas, Facultat de Medicina, Instituto de Neurociencias, Universitat de Barcelona, Barcelona, Spain
| | | | - Andreas Weiss
- IRBM Promidis, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy.,Evotec AG, Manfred Eigen Campus, Hamburg, Germany
| | - Alberto Bresciani
- IRBM Science Park, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy
| | - Jean-Paul Gerard Vonsattel
- Taub Institute for Research on Alzheimer's disease and the Aging Brain, Columbia University Medical Center, 710 West 168th Street, New York, NY, 10032, USA
| | - Lara Petricca
- IRBM Science Park, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy.,IRBM Promidis, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy
| | - J Lawrence Marsh
- Department of Developmental and Cell Biology, University of California, Irvine, 92697, USA
| | - Silvia Gines
- Departamento de Ciencias Biomedicas, Facultat de Medicina, Instituto de Neurociencias, Universitat de Barcelona, Barcelona, Spain
| | - Iolanda Santimone
- Huntington and Rare Diseases Unit, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Massimo Marano
- Huntington and Rare Diseases Unit, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Station 19, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Ferdinando Squitieri
- Huntington and Rare Diseases Unit, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Andrea Caricasole
- IRBM Science Park, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy. .,IRBM Promidis, Via Pontina km 30.600, 00071, Pomezia, Rome, Italy.
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Fodale V, Kegulian NC, Verani M, Cariulo C, Azzollini L, Petricca L, Daldin M, Boggio R, Padova A, Kuhn R, Pacifici R, Macdonald D, Schoenfeld RC, Park H, Isas JM, Langen R, Weiss A, Caricasole A. Polyglutamine- and temperature-dependent conformational rigidity in mutant huntingtin revealed by immunoassays and circular dichroism spectroscopy. PLoS One 2014; 9:e112262. [PMID: 25464275 PMCID: PMC4251833 DOI: 10.1371/journal.pone.0112262] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 10/06/2014] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND In Huntington's disease, expansion of a CAG triplet repeat occurs in exon 1 of the huntingtin gene (HTT), resulting in a protein bearing>35 polyglutamine residues whose N-terminal fragments display a high propensity to misfold and aggregate. Recent data demonstrate that polyglutamine expansion results in conformational changes in the huntingtin protein (HTT), which likely influence its biological and biophysical properties. Developing assays to characterize and measure these conformational changes in isolated proteins and biological samples would advance the testing of novel therapeutic approaches aimed at correcting mutant HTT misfolding. Time-resolved Förster energy transfer (TR-FRET)-based assays represent high-throughput, homogeneous, sensitive immunoassays widely employed for the quantification of proteins of interest. TR-FRET is extremely sensitive to small distances and can therefore provide conformational information based on detection of exposure and relative position of epitopes present on the target protein as recognized by selective antibodies. We have previously reported TR-FRET assays to quantify HTT proteins based on the use of antibodies specific for different amino-terminal HTT epitopes. Here, we investigate the possibility of interrogating HTT protein conformation using these assays. METHODOLOGY/PRINCIPAL FINDINGS By performing TR-FRET measurements on the same samples (purified recombinant proteins or lysates from cells expressing HTT fragments or full length protein) at different temperatures, we have discovered a temperature-dependent, reversible, polyglutamine-dependent conformational change of wild type and expanded mutant HTT proteins. Circular dichroism spectroscopy confirms the temperature and polyglutamine-dependent change in HTT structure, revealing an effect of polyglutamine length and of temperature on the alpha-helical content of the protein. CONCLUSIONS/SIGNIFICANCE The temperature- and polyglutamine-dependent effects observed with TR-FRET on HTT proteins represent a simple, scalable, quantitative and sensitive assay to identify genetic and pharmacological modulators of mutant HTT conformation, and potentially to assess the relevance of conformational changes during onset and progression of Huntington's disease.
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Affiliation(s)
| | - Natalie C. Kegulian
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | | | | | | | | | | | | | | | | | - Robert Pacifici
- CHDI Management/CHDI Foundation, Los Angeles, California, United States of America
| | - Douglas Macdonald
- CHDI Management/CHDI Foundation, Los Angeles, California, United States of America
| | - Ryan C. Schoenfeld
- CHDI Management/CHDI Foundation, Los Angeles, California, United States of America
| | - Hyunsun Park
- CHDI Management/CHDI Foundation, Los Angeles, California, United States of America
| | - J. Mario Isas
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Ralf Langen
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail: (RL); (AW); (AC)
| | - Andreas Weiss
- IRBM Promidis, Pomezia, Rome, Italy
- * E-mail: (RL); (AW); (AC)
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