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Janarthanam C, Clabaugh G, Wang Z, Melvin BR, Scheibe I, Jin H, Anantharam V, Urbauer RJB, Urbauer JL, Ma J, Kanthasamy A, Huang X, Donadio V, Zou W, Kanthasamy AG. High-Yield α-Synuclein Purification and Ionic Strength Modification Pivotal to Seed Amplification Assay Performance and Reproducibility. Int J Mol Sci 2024; 25:5988. [PMID: 38892177 PMCID: PMC11172462 DOI: 10.3390/ijms25115988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/17/2024] [Accepted: 05/23/2024] [Indexed: 06/21/2024] Open
Abstract
Alpha-synuclein seed amplification assays (αSyn-SAAs) have emerged as promising diagnostic tools for Parkinson's disease (PD) by detecting misfolded αSyn and amplifying the signal through cyclic shaking and resting in vitro. Recently, our group and others have shown that multiple biospecimens, including CSF, skin, and submandibular glands (SMGs), can be used to seed the aggregation reaction and robustly distinguish between patients with PD and non-disease controls. The ultrasensitivity of the assay affords the ability to detect minute quantities of αSyn in peripheral tissues, but it also produces various technical challenges of variability. To address the problem of variability, we present a high-yield αSyn protein purification protocol for the efficient production of monomers with a low propensity for self-aggregation. We expressed wild-type αSyn in BL21 Escherichia coli, lysed the cells using osmotic shock, and isolated αSyn using acid precipitation and fast protein liquid chromatography (FPLC). Following purification, we optimized the ionic strength of the reaction buffer to distinguish the fluorescence maximum (Fmax) separation between disease and healthy control tissues for enhanced assay performance. Our protein purification protocol yielded high quantities of αSyn (average: 68.7 mg/mL per 1 L of culture) and showed highly precise and robust αSyn-SAA results using brain, skin, and SMGs with inter-lab validation.
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Affiliation(s)
- Chelva Janarthanam
- Center for Neurological Disease Research, Department of Physiology and Pharmacology, University of Georgia, Athens, GA 30602, USA; (C.J.); (G.C.); (I.S.); (H.J.); (V.A.); (A.K.)
| | - Griffin Clabaugh
- Center for Neurological Disease Research, Department of Physiology and Pharmacology, University of Georgia, Athens, GA 30602, USA; (C.J.); (G.C.); (I.S.); (H.J.); (V.A.); (A.K.)
| | - Zerui Wang
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA;
| | - Bradley R. Melvin
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA;
| | - Ileia Scheibe
- Center for Neurological Disease Research, Department of Physiology and Pharmacology, University of Georgia, Athens, GA 30602, USA; (C.J.); (G.C.); (I.S.); (H.J.); (V.A.); (A.K.)
| | - Huajun Jin
- Center for Neurological Disease Research, Department of Physiology and Pharmacology, University of Georgia, Athens, GA 30602, USA; (C.J.); (G.C.); (I.S.); (H.J.); (V.A.); (A.K.)
| | - Vellareddy Anantharam
- Center for Neurological Disease Research, Department of Physiology and Pharmacology, University of Georgia, Athens, GA 30602, USA; (C.J.); (G.C.); (I.S.); (H.J.); (V.A.); (A.K.)
| | - Ramona J. B. Urbauer
- Department of Chemistry, University of Georgia, Athens, GA 30602, USA; (R.J.B.U.); (J.L.U.)
| | - Jeffrey L. Urbauer
- Department of Chemistry, University of Georgia, Athens, GA 30602, USA; (R.J.B.U.); (J.L.U.)
| | - Jiyan Ma
- Chinese Institute for Brain Research, Beijing 102206, China;
| | - Arthi Kanthasamy
- Center for Neurological Disease Research, Department of Physiology and Pharmacology, University of Georgia, Athens, GA 30602, USA; (C.J.); (G.C.); (I.S.); (H.J.); (V.A.); (A.K.)
| | - Xuemei Huang
- Department of Neurology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA;
| | - Vincenzo Donadio
- IRCCS Institute of Neurological Sciences of Bologna, Complex Operational Unit Clinica Neurologica, 40138 Bologna, Italy;
| | - Wenquan Zou
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA;
| | - Anumantha G. Kanthasamy
- Center for Neurological Disease Research, Department of Physiology and Pharmacology, University of Georgia, Athens, GA 30602, USA; (C.J.); (G.C.); (I.S.); (H.J.); (V.A.); (A.K.)
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Thakkar H, Chatterjee S, Saxena P, Eerla R, Wagh S, Khairnar A, Shah RP. Cell-Engineered Recombinant α-Synuclein: A Gage R&R Validated Protocol. J Proteome Res 2024; 23:16-24. [PMID: 37985371 DOI: 10.1021/acs.jproteome.3c00190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
α-Synuclein (α-Syn) misfolding and its presence in Lewy bodies are observed in almost all Parkinson's disease (PD) patients. Basic biomedical research would benefit from a quick, low-cost approach to purifying α-Syn and developing in vitro and in vivo models for PD. Several research groups utilize PFF-based models, yet the production of α-Syn PFFs is inconsistent, resulting in nonconclusive findings. Some research laboratories prepare recombinant α-Syn (r α-Syn) by molecular cloning to overexpress α-Syn with various purifying techniques. Laboratory-to-laboratory protocols cause considerable variability and sometimes contradictory findings. PD researchers spend more on protein than solving α-Syn's riddles. This article uncovered a novel method for expressing and purifying r α-Syn validated through gage reproducibility and repeatability (Gage R&R). For the production of r α-Syn, we have employed the ability of a high-cell-density-based expression system to overexpress protein in BL21(DE3). A simple, high-throughput, nonchromatographical purification protocol has been devised to facilitate research with higher reproducibility, which was validated through Gage R&R. A crossover experimental design was utilized, and the purified protein was characterized using orthogonal high-end analytical methods, which displayed higher similarity between the isolated r α-Syn. Batch-to-batch variability was the least for produced protein and hence can be utilized for exploring the iceberg of PD.
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Affiliation(s)
- Harsh Thakkar
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research─Ahmedabad (NIPER-A), Opposite Air force Station Palaj, Gandhinagar 382355, Gujarat India
| | - Sayan Chatterjee
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research─Ahmedabad (NIPER-A), Opposite Air force Station Palaj, Gandhinagar 382355, Gujarat India
| | - Purvi Saxena
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research─Ahmedabad (NIPER-A), Opposite Air force Station Palaj, Gandhinagar 382355, Gujarat India
| | - Rameswari Eerla
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research─Ahmedabad (NIPER-A), Opposite Air force Station Palaj, Gandhinagar 382355, Gujarat India
| | - Sachin Wagh
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research─Ahmedabad (NIPER-A), Opposite Air force Station Palaj, Gandhinagar 382355, Gujarat India
| | - Amit Khairnar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research─Ahmedabad (NIPER-A), Opposite Air force Station Palaj, Gandhinagar 382355, Gujarat India
| | - Ravi P Shah
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research─Ahmedabad (NIPER-A), Opposite Air force Station Palaj, Gandhinagar 382355, Gujarat India
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Buzzatto MV, Berberián MV, Di Bartolo AL, Masone D, Tomes CN. α-Synuclein is required for sperm exocytosis at a post-fusion stage. Front Cell Dev Biol 2023; 11:1125988. [PMID: 37287458 PMCID: PMC10242118 DOI: 10.3389/fcell.2023.1125988] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 05/09/2023] [Indexed: 06/09/2023] Open
Abstract
The sperm acrosome is a large dense-core granule whose contents are secreted by regulated exocytosis at fertilization through the opening of numerous fusion pores between the acrosomal and plasma membranes. In other cells, the nascent pore generated when the membrane surrounding a secretory vesicle fuses with the plasma membrane may have different fates. In sperm, pore dilation leads to the vesiculation and release of these membranes, together with the granule contents. α-Synuclein is a small cytosolic protein claimed to exhibit different roles in exocytic pathways in neurons and neuroendocrine cells. Here, we scrutinized its function in human sperm. Western blot revealed the presence of α-synuclein and indirect immunofluorescence its localization to the acrosomal domain of human sperm. Despite its small size, the protein was retained following permeabilization of the plasma membrane with streptolysin O. α-Synuclein was required for acrosomal release, as demonstrated by the inability of an inducer to elicit exocytosis when permeabilized human sperm were loaded with inhibitory antibodies to human α-synuclein. The antibodies halted calcium-induced secretion when introduced after the acrosome docked to the cell membrane. Two functional assays, fluorescence and transmission electron microscopies revealed that the stabilization of open fusion pores was responsible for the secretion blockage. Interestingly, synaptobrevin was insensitive to neurotoxin cleavage at this point, an indication of its engagement in cis SNARE complexes. The very existence of such complexes during AE reflects a new paradigm. Recombinant α-synuclein rescued the inhibitory effects of the anti-α-synuclein antibodies and of a chimeric Rab3A-22A protein that also inhibits AE after fusion pore opening. We applied restrained molecular dynamics simulations to compare the energy cost of expanding a nascent fusion pore between two model membranes and found it higher in the absence than in the presence of α-synuclein. Hence, our results suggest that α-synuclein is essential for expanding fusion pores.
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Affiliation(s)
- Micaela Vanina Buzzatto
- Instituto de Histología y Embriología de Mendoza (IHEM)-CONICET-Universidad Nacional de Cuyo, Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - María Victoria Berberián
- Instituto de Histología y Embriología de Mendoza (IHEM)-CONICET-Universidad Nacional de Cuyo, Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
- Instituto de Ciencias Básicas (ICB)-CONICET-Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Ary Lautaro Di Bartolo
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Diego Masone
- Instituto de Histología y Embriología de Mendoza (IHEM)-CONICET-Universidad Nacional de Cuyo, Mendoza, Argentina
- Facultad de Ingeniería, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Claudia Nora Tomes
- Instituto de Histología y Embriología de Mendoza (IHEM)-CONICET-Universidad Nacional de Cuyo, Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
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Hernandez SM, Tikhonova EB, Baca KR, Zhao F, Zhu X, Karamyshev AL. Unexpected Implication of SRP and AGO2 in Parkinson's Disease: Involvement in Alpha-Synuclein Biogenesis. Cells 2021; 10:2792. [PMID: 34685771 PMCID: PMC8534902 DOI: 10.3390/cells10102792] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/09/2021] [Accepted: 10/12/2021] [Indexed: 01/21/2023] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder classified by the loss of dopaminergic neurons in the substantia nigra pars compacta, the region of the brain that is responsible for motor control. Surviving neurons in this region contain aggregated protein alpha-Synuclein (αSyn) in the form of cytoplasmic inclusions, referred to as Lewy bodies. Changes in αSyn expression are also associated with PD and its progression. Previously, we demonstrated that signal recognition particle (SRP) and Argonaute 2 (AGO2) proteins are involved in protein quality control at the ribosome during translation. We also demonstrated that SRP has an mRNA protection function in addition to a protein targeting function, thus controlling mRNA and protein expression. In this study, we tested involvement of these factors in αSyn biogenesis. We hypothesize that loss of these factors may interfere with αSyn expression, and subsequently, be associated with PD. Using depletion assays in human cell culture and analysis of these proteins in the brains of deceased PD patients, we demonstrate that SRP and AGO2 are involved in the control of αSyn expression and AGO2 has reduced expression in PD. We show for the first time that SRP is involved in mRNA protection of αSyn, a protein that does not have a signal sequence or transmembrane span. Our findings suggest that SRP may interact with a hydrophobic domain in the middle of αSyn during translation. Understanding the molecular mechanisms controlling αSyn biogenesis in cells is vital to developing preventative therapies against PD.
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Affiliation(s)
- Sarah M. Hernandez
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (S.M.H.); (E.B.T.); (K.R.B.)
| | - Elena B. Tikhonova
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (S.M.H.); (E.B.T.); (K.R.B.)
| | - Kristen R. Baca
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (S.M.H.); (E.B.T.); (K.R.B.)
- Center for the Integration of STEM Education and Research (CISER), Texas Tech University, Lubbock, TX 79409, USA
| | - Fanpeng Zhao
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA; (F.Z.); (X.Z.)
| | - Xiongwei Zhu
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA; (F.Z.); (X.Z.)
| | - Andrey L. Karamyshev
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (S.M.H.); (E.B.T.); (K.R.B.)
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Pan B, Park JH, Ramlall T, Eliezer D, Rhoades E, Petersson EJ. Chemoenzymatic Semi-synthesis Enables Efficient Production of Isotopically Labeled α-Synuclein with Site-Specific Tyrosine Phosphorylation. Chembiochem 2021; 22:1440-1447. [PMID: 33274519 PMCID: PMC8185324 DOI: 10.1002/cbic.202000742] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/02/2020] [Indexed: 11/12/2022]
Abstract
Post-translational modifications (PTMs) can affect the normal function and pathology of α-synuclein (αS), an amyloid-fibril-forming protein linked to Parkinson's disease. Phosphorylation of αS Tyr39 has recently been found to display a dose-dependent effect on fibril formation kinetics and to alter the morphology of the fibrils. Existing methods to access site-specifically phosphorylated αS for biochemical studies include total or semi-synthesis by native chemical ligation (NCL) as well as chemoenzymatic methods to phosphorylate peptides, followed by NCL. Here, we investigated a streamlined method to produce large quantities of phosphorylated αS by co-expressing a kinase with a protein fragment in Escherichia coli. We also introduced the use of methyl thioglycolate (MTG) to enable one-pot NCL and desulfurization. We compare our optimized methods to previous reports and show that we can achieve the highest yields of site-specifically phosphorylated protein through chemoenzymatic methods using MTG, and that our strategy is uniquely well suited to producing 15 N-labeled, phosphorylated protein for NMR studies.
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Affiliation(s)
- Buyan Pan
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street; Philadelphia, Pennsylvania 19104-6323, USA
| | - Joo Hyung Park
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street; Philadelphia, Pennsylvania 19104-6323, USA
| | - Trudy Ramlall
- Department of Biochemistry, Weill Cornell Medicine, 1300 York Avenue; New York, NY, 10065
| | - David Eliezer
- Department of Biochemistry, Weill Cornell Medicine, 1300 York Avenue; New York, NY, 10065
| | - Elizabeth Rhoades
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street; Philadelphia, Pennsylvania 19104-6323, USA
| | - E. James Petersson
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street; Philadelphia, Pennsylvania 19104-6323, USA
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Cytotoxicity and Mitochondrial Dysregulation Caused by α-Synuclein in Dictyostelium discoideum. Cells 2020; 9:cells9102289. [PMID: 33066427 PMCID: PMC7602147 DOI: 10.3390/cells9102289] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
Alpha synuclein has been linked to both sporadic and familial forms of Parkinson’s disease (PD) and is the most abundant protein in Lewy bodies a hallmark of Parkinson’s disease. The function of this protein and the molecular mechanisms underlying its toxicity are still unclear, but many studies have suggested that the mechanism of α-synuclein toxicity involves alterations to mitochondrial function. Here we expressed human α-synuclein and two PD-causing α-synuclein mutant proteins (with a point mutation, A53T, and a C-terminal 20 amino acid truncation) in the eukaryotic model Dictyostelium discoideum. Mitochondrial disease has been well studied in D. discoideum and, unlike in mammals, mitochondrial dysfunction results in a clear set of defective phenotypes. These defective phenotypes are caused by the chronic hyperactivation of the cellular energy sensor, AMP-activated protein kinase (AMPK). Expression of α-synuclein wild type and mutant forms was toxic to the cells and mitochondrial function was dysregulated. Some but not all of the defective phenotypes could be rescued by down regulation of AMPK revealing both AMPK-dependent and -independent mechanisms. Importantly, we also show that the C-terminus of α-synuclein is required and sufficient for the localisation of the protein to the cell cortex in D. discoideum.
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Nelson TJ, Truong T, Truong B, Bilyeu CV, Zhao J, Stains CI. A luminescence-based assay for monitoring changes in alpha-synuclein aggregation in living cells. RSC Adv 2020; 10:16675-16678. [PMID: 32489651 PMCID: PMC7266166 DOI: 10.1039/d0ra02720k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Parkinson's disease is characterized by the accumulation of protein aggregates in the brain, termed Lewy bodies. Lewy bodies are predominantly composed of α-synuclein and mutations that increase the aggregation potential of α-synuclein have been associated with early on-set disease. Assays capable of reporting on the solubility of α-synuclein in living cells could provide a means to interrogate the influence of mutations on aggregation as well as identify small molecules capable of modulating the aggregation of α-synuclein. Herein, we repurpose our previously reported self-assembling NanoLuc luciferase fragments to engineer a platform for detecting α-synuclein solubility in living cells. This new assay is capable of reporting on changes in α-synuclein solubility caused by disease-relevant mutations as well as inhibitors of aggregation. In the long term, this new assay platform provides a means to investigate the influence of mutations on α-synuclein solubility as well as identify potential tool compounds capable of modulating α-synuclein aggregation.
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Affiliation(s)
- Travis J Nelson
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA
| | - Tiffany Truong
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA
| | - BaoLong Truong
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA
| | - Camden V Bilyeu
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA
| | - Jia Zhao
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA
| | - Cliff I Stains
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA.,Nebraska Center for Integrated Biomolecular Communication, University of Nebraska - Lincoln, Lincoln, NE 68588, USA.,Cancer Genes and Molecular Regulation Program, Fred & Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA.,University of Virginia Cancer Center, University of Virginia, Charlottesville, VA, 22904, USA
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Abstract
α-Synuclein (αS) is an abundant neuronal protein which has been implicated, among others, in the pathogenesis of neurodegenerative diseases like Parkinson's disease (PD) and dementia with Lewy bodies (DLB). In fact, αS is the major constituent of Lewy bodies, the primarily proteinaceous inclusions found in the nervous tissue of PD and DLB patients. While its physiological role is unclear, it is believed to be involved in the regulation of synaptic vesicle exocytosis. However, in a disease state, αS will "misfold" and aggregate, leading to neuronal dysfunction and death. The study of the molecular events underlying pathogenesis, especially with biophysical and biochemical approaches, requires highly pure untagged αS. In this protocol we describe a method to purify untagged recombinant αS, which can be used for binding, folding, and aggregation studies. The purification method includes a cell lysis step, followed by two chromatography steps: ion-exchange chromatography first, and size-exclusion chromatography for polishing.
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Narkiewicz J, Giachin G, Legname G. In vitro aggregation assays for the characterization of α-synuclein prion-like properties. Prion 2015; 8:19-32. [PMID: 24552879 PMCID: PMC4116381 DOI: 10.4161/pri.28125] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Aggregation of α-synuclein plays a crucial role in the pathogenesis of synucleinopathies, a group of neurodegenerative diseases including Parkinson disease (PD), dementia with Lewy bodies (DLB), diffuse Lewy body disease (DLBD) and multiple system atrophy (MSA). The common feature of these diseases is a pathological deposition of protein aggregates, known as Lewy bodies (LBs) in the central nervous system. The major component of these aggregates is α-synuclein, a natively unfolded protein, which may undergo dramatic structural changes resulting in the formation of β-sheet rich assemblies. In vitro studies have shown that recombinant α-synuclein protein may polymerize into amyloidogenic fibrils resembling those found in LBs. These aggregates may be uptaken and propagated between cells in a prion-like manner. Here we present the mechanisms and kinetics of α-synuclein aggregation in vitro, as well as crucial factors affecting this process. We also describe how PD-linked α-synuclein mutations and some exogenous factors modulate in vitro aggregation. Furthermore, we present a current knowledge on the mechanisms by which extracellular aggregates may be internalized and propagated between cells, as well as the mechanisms of their toxicity.
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Coelho-Cerqueira E, Carmo-Gonçalves P, Sá Pinheiro A, Cortines J, Follmer C. α-Synuclein as an intrinsically disordered monomer - fact or artefact? FEBS J 2013; 280:4915-27. [DOI: 10.1111/febs.12471] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 07/12/2013] [Accepted: 07/31/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Eduardo Coelho-Cerqueira
- Department of Physical Chemistry; Institute of Chemistry; Federal University of Rio de Janeiro; Brazil
| | - Phelippe Carmo-Gonçalves
- Department of Physical Chemistry; Institute of Chemistry; Federal University of Rio de Janeiro; Brazil
| | - Anderson Sá Pinheiro
- Department of Biochemistry; Institute of Chemistry; Federal University of Rio de Janeiro; Brazil
| | - Juliana Cortines
- Department of Virology; Institute of Microbiology Paulo de Góes; Federal University of Rio de Janeiro; Brazil
| | - Cristian Follmer
- Department of Physical Chemistry; Institute of Chemistry; Federal University of Rio de Janeiro; Brazil
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One single method to produce native and Tat-fused recombinant human α-synuclein in Escherichia coli. BMC Biotechnol 2013; 13:32. [PMID: 23557146 PMCID: PMC3621789 DOI: 10.1186/1472-6750-13-32] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 03/25/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Human α-synuclein is a small-sized, natively unfolded protein that in fibrillar form is the primary component of Lewy bodies, the pathological hallmark of Parkinson's disease. Experimental evidence suggests that α-synuclein aggregation is the key event that triggers neurotoxicity although additional findings have proposed a protective role of α-synuclein against oxidative stress. One way to address the mechanism of this protective action is to evaluate α-synuclein-mediated protection by delivering this protein inside cells using a chimeric protein fused with the Tat-transduction domain of HIV Tat, named TAT-α-synuclein. RESULTS A reliable protocol was designed to efficiently express and purify two different forms of human α-synuclein. The synthetic cDNAs encoding for the native α-synuclein and the fusion protein with the transduction domain of Tat protein from HIV were overexpressed in a BL21(DE3) E. coli strain as His-tagged proteins. The recombinant proteins largely localized (≥ 85%) to the periplasmic space. By using a quick purification protocol, based on recovery of periplasmic space content and metal-chelating chromatography, the recombinant α-synuclein protein forms could be purified in a single step to ≥ 95% purity. Both α-synuclein recombinant proteins form fibrils and the TAT-α-synuclein is also cytotoxic in the micromolar concentration range. CONCLUSIONS To further characterize the molecular mechanisms of α-synuclein neurotoxicity both in vitro and in vivo and to evaluate the relevance of extracellular α-synuclein for the pathogenesis and progression of Parkinson's disease, a suitable method to produce different high-quality forms of this pathological protein is required. Our optimized expression and purification procedure offers an easier and faster means of producing different forms (i.e., both the native and the TAT-fusion form) of soluble recombinant α-synuclein than previously described procedures.
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Codolo G, Plotegher N, Pozzobon T, Brucale M, Tessari I, Bubacco L, de Bernard M. Triggering of inflammasome by aggregated α-synuclein, an inflammatory response in synucleinopathies. PLoS One 2013; 8:e55375. [PMID: 23383169 PMCID: PMC3561263 DOI: 10.1371/journal.pone.0055375] [Citation(s) in RCA: 426] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 12/22/2012] [Indexed: 12/20/2022] Open
Abstract
Parkinson’s disease (PD) is one of the most common neurodegenerative diseases. It is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta of the brain. Another feature is represented by the formation in these cells of inclusions called Lewy bodies (LB), principally constituted by fibrillar α-synuclein (αSyn). This protein is considered a key element in the aetiology of a group of neurodegenerative disorders termed synucleinopathies, which include PD, but the cellular and molecular mechanisms involved are not completely clear. It is established that the inflammatory process plays a crucial role in the pathogenesis and/or progression of PD; moreover, it is known that aggregated αSyn, released by neurons, activates microglia cells to produce pro-inflammatory mediators, such as IL-1β. IL-1β is one of the strongest pro-inflammatory cytokines; it is produced as an inactive mediator, and its maturation and activation requires inflammasome activation. In particular, the NLRP3 inflammasome is activated by a wide variety of stimuli, among which are crystallized and particulate material. In this work, we investigated the possibility that IL-1β production, induced by fibrillar αSyn, is involved the inflammasome activation. We demonstrated the competence of monomeric and fibrillar αSyn to induce synthesis of IL-1β, through TLR2 interaction; we found that the secretion of the mature cytokine was a peculiarity of the fibrillated protein. Moreover, we observed that the secretion of IL-1β involves NLRP3 inflammasome activation. The latter relies on the phagocytosis of fibrillar αSyn, followed by increased ROS production and cathepsin B release into the cytosol. Taken together, our data support the notion that fibrillar αSyn, likely released by neuronal degeneration, acts as an endogenous trigger inducing a strong inflammatory response in PD.
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Affiliation(s)
- Gaia Codolo
- Department of Biology, University of Padua, Padua, Italy
- Venetian Institute of Molecular Medicine, Padua, Italy
| | | | | | - Marco Brucale
- National Research Council (CNR), Institute of Nanostructured Materials (ISMN), Montelibretti, Rome, Italy
| | | | - Luigi Bubacco
- Department of Biology, University of Padua, Padua, Italy
- * E-mail: (MdB); (LB)
| | - Marina de Bernard
- Department of Biology, University of Padua, Padua, Italy
- Venetian Institute of Molecular Medicine, Padua, Italy
- * E-mail: (MdB); (LB)
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Alpha-synuclein pore forming activity upon membrane association. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2876-83. [DOI: 10.1016/j.bbamem.2012.07.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 07/09/2012] [Accepted: 07/11/2012] [Indexed: 01/31/2023]
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14
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Meng E, Cai TF, Li WY, Zhang H, Liu YB, Peng K, Liang S, Zhang DY. Functional expression of spider neurotoxic peptide huwentoxin-I in E. coli. PLoS One 2011; 6:e21608. [PMID: 21731778 PMCID: PMC3121796 DOI: 10.1371/journal.pone.0021608] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Accepted: 06/03/2011] [Indexed: 11/18/2022] Open
Abstract
The coding sequence of huwentoxin-I, a neurotoxic peptide isolated from the venom of the Chinese spider Ornithoctonus huwena, was amplified by PCR using the cDNA library constructed from the spider venom glands. The cloned fragment was inserted into the expression vector pET-40b and transformed into the E. coli strain BL21 (DE3). The expression of a soluble fusion protein, disulfide interchange protein (DsbC)-huwentoxin-I, was auto-induced in the periplasm of E. coli in the absence of IPTG. After partial purification using a Ni-NTA column, the expressed fusion protein was digested using enterokinase to release heteroexpressed huwentoxin-I and was further purified using RP-HPLC. The resulting peptide was subjected to gel electrophoresis and mass spectrometry analysis. The molecular weight of the heteroexpressed huwentoxin-I was 3750.69, which is identical to that of the natural form of the peptide isolated from spider venom. The physiological properties of the heteroexpressed huwentoxin-I were further analyzed using a whole-cell patch clamp assay. The heteroexpressed huwentoxin-I was able to block currents generated by human Na(v1.7) at an IC₅₀ of 640 nmole/L, similar to that of the natural huwentoxin-I, which is 630 nmole/L.
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Affiliation(s)
- Er Meng
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
- Research Center of Biological Information, College of Science, National University of Defense Technology, Changsha, Hunan, China
| | - Tian-Fu Cai
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
| | - Wen-Ying Li
- Research Center of Biological Information, College of Science, National University of Defense Technology, Changsha, Hunan, China
| | - Hui Zhang
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
| | - Yan-Bo Liu
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
| | - Kuan Peng
- Core Facilities of Biotechnology, Central South University of Forestry and Technology, Changsha, Hunan, China
| | - Songping Liang
- Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
- * E-mail: (SL); (DYZ)
| | - Dong-Yi Zhang
- Research Center of Biological Information, College of Science, National University of Defense Technology, Changsha, Hunan, China
- * E-mail: (SL); (DYZ)
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15
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Slade KM, Baker R, Chua M, Thompson NL, Pielak GJ. Effects of recombinant protein expression on green fluorescent protein diffusion in Escherichia coli. Biochemistry 2009; 48:5083-9. [PMID: 19413350 DOI: 10.1021/bi9004107] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fluorescence recovery after photobleaching was used to measure the diffusion coefficient of green fluorescent protein (GFP, 27 kDa) in Escherichia coli in the presence or absence of four coexpressed proteins: cytoplasmic maltose binding protein (42 kDa), tau-40 (45 kDa), alpha-synuclein (14 kDa), or calmodulin (17 kDa). The GFP diffusion coefficient remains constant regardless of the type of coexpresseed protein and whether or not the coexpressed protein was induced. We conclude that expression of these soluble proteins has little to no effect on the diffusion of GFP. These results have implications for the utility of in-cell nuclear magnetic resonance spectroscopy.
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Affiliation(s)
- Kristin M Slade
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, USA
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16
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Croke RL, Sallum CO, Watson E, Watt ED, Alexandrescu AT. Hydrogen exchange of monomeric alpha-synuclein shows unfolded structure persists at physiological temperature and is independent of molecular crowding in Escherichia coli. Protein Sci 2008; 17:1434-45. [PMID: 18493022 DOI: 10.1110/ps.033803.107] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Amide proton NMR signals from the N-terminal domain of monomeric alpha-synuclein (alphaS) are lost when the sample temperature is raised from 10 degrees C to 35 degrees C at pH 7.4. Although the temperature-induced effects have been attributed to conformational exchange caused by an increase in alpha-helix structure, we show that the loss of signals is due to fast amide proton exchange. At low ionic strength, hydrogen exchange rates are faster for the N-terminal segment of alphaS than for the acidic C-terminal domain. When the salt concentration is raised to 300 mM, exchange rates increase throughout the protein and become similar for the N- and C-terminal domains. This indicates that the enhanced protection of amide protons from the C-terminal domain at low salt is electrostatic in nature. Calpha chemical shift data point to <10% residual alpha-helix structure at 10 degrees C and 35 degrees C. Conformational exchange contributions to R2 are negligible at both temperatures. In contrast to the situation in vitro, the majority of amide protons are observed at 37 degrees C in 1H-15N HSQC spectra of alphaS encapsulated within living Escherichia coli cells. Our finding that temperature effects on alphaS NMR spectra can be explained by hydrogen exchange obviates the need to invoke special cellular factors. The retention of signals is likely due to slowed hydrogen exchange caused by the lowered intracellular pH of high-density E. coli cultures. Taken together, our results emphasize that alphaS remains predominantly unfolded at physiological temperature and pH-an important conclusion for mechanistic models of the association of alphaS with membranes and fibrils.
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Affiliation(s)
- Robyn L Croke
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269-3125, USA
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