151
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Sulzer D, Edwards RH. The physiological role of α-synuclein and its relationship to Parkinson's Disease. J Neurochem 2019; 150:475-486. [PMID: 31269263 PMCID: PMC6707892 DOI: 10.1111/jnc.14810] [Citation(s) in RCA: 196] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/03/2019] [Accepted: 06/28/2019] [Indexed: 12/15/2022]
Abstract
The protein α-synuclein has a central role in the pathogenesis of Parkinson's disease (PD). In this review, we discuss recent results concerning its primary function, which appears to be on cell membranes. The pre-synaptic location of synuclein has suggested a role in neurotransmitter release and it apparently associates with synaptic vesicles because of their high curvature. Indeed, synuclein over-expression inhibits synaptic vesicle exocytosis. However, loss of synuclein has not yet been shown to have a major effect on synaptic transmission. Consistent with work showing that synuclein can promote as well as sense membrane curvature, recent analysis of synuclein triple knockout mice now shows that synuclein accelerates dilation of the exocytic fusion pore. This form of regulation affects primarily the release of slowly discharged lumenal cargo such as neural peptides, but presumably also contributes to maintenance of the release site. This article is part of the Special Issue "Synuclein".
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Affiliation(s)
- David Sulzer
- Departments of Psychiatry, Neurology and Pharmacology, Columbia University Medical Center, New York State Psychiatric Institute
| | - Robert H Edwards
- Departments of Neurology and Physiology, Graduate Programs in Cell Biology, Biomedical Sciences and Neuroscience, UCSF School of Medicine
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152
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Masato A, Plotegher N, Boassa D, Bubacco L. Impaired dopamine metabolism in Parkinson's disease pathogenesis. Mol Neurodegener 2019; 14:35. [PMID: 31488222 PMCID: PMC6728988 DOI: 10.1186/s13024-019-0332-6] [Citation(s) in RCA: 154] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 07/22/2019] [Indexed: 12/14/2022] Open
Abstract
A full understanding of Parkinson's Disease etiopathogenesis and of the causes of the preferential vulnerability of nigrostriatal dopaminergic neurons is still an unsolved puzzle. A multiple-hit hypothesis has been proposed, which may explain the convergence of familial, environmental and idiopathic forms of the disease. Among the various determinants of the degeneration of the neurons in Substantia Nigra pars compacta, in this review we will focus on the endotoxicity associated to dopamine dyshomeostasis. In particular, we will discuss the relevance of the reactive dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL) in the catechol-induced neurotoxicity. Indeed, the synergy between the catechol and the aldehyde moieties of DOPAL exacerbates its reactivity, resulting in modification of functional protein residues, protein aggregation, oxidative stress and cell death. Interestingly, αSynuclein, whose altered proteostasis is a recurrent element in Parkinson's Disease pathology, is considered a preferential target of DOPAL modification. DOPAL triggers αSynuclein oligomerization leading to synapse physiology impairment. Several factors can be responsible for DOPAL accumulation at the pre-synaptic terminals, i.e. dopamine leakage from synaptic vesicles, increased rate of dopamine conversion to DOPAL by upregulated monoamine oxidase and decreased DOPAL degradation by aldehyde dehydrogenases. Various studies report the decreased expression and activity of aldehyde dehydrogenases in parkinsonian brains, as well as genetic variants associated to increased risk in developing the pathology. Thus, we discuss how the deregulation of these enzymes might be considered a contributing element in the pathogenesis of Parkinson's Disease or a down-stream effect. Finally, we propose that a better understanding of the impaired dopamine metabolism in Parkinson's Disease would allow a more refined patients stratification and the design of more targeted and successful therapeutic strategies.
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Affiliation(s)
- Anna Masato
- Department of Biology, University of Padova, Padova, Italy
| | | | - Daniela Boassa
- Department of Neurosciences, and National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, CA, USA
| | - Luigi Bubacco
- Department of Biology, University of Padova, Padova, Italy.
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153
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Alam P, Bousset L, Melki R, Otzen DE. α-synuclein oligomers and fibrils: a spectrum of species, a spectrum of toxicities. J Neurochem 2019; 150:522-534. [PMID: 31254394 DOI: 10.1111/jnc.14808] [Citation(s) in RCA: 176] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/05/2019] [Accepted: 06/21/2019] [Indexed: 12/14/2022]
Abstract
This review article provides an overview of the different species that α-synuclein aggregates can populate. It also attempts to reconcile conflicting views regarding the cytotoxic roles of oligomers versus fibrils. α-synuclein, while highly dynamic in the monomeric state, can access a large number of different assembly states. Depending on assembly conditions, these states can interconvert over different timescales. The fibrillar state is the most thermodynamically favored due to the many stabilizing interactions formed between each monomeric unit, but different fibrillar types form at different rates. The end distribution is likely to reflect kinetic partitioning as much as thermodynamic equilibra. In addition, metastable oligomeric species, some of which are on-pathway and others off-pathway, can be populated for remarkably long periods of time. Chemical modifications (phosphorylation, oxidation, covalent links to ligands, etc.) perturb these physical interconversions and invariably destabilize the fibrillar state, leading to small prefibrillar assemblies which can coalesce into amorphous states. Both oligomeric and fibrillar species have been shown to be cytotoxic although firm conclusions require very careful evaluation of particle concentrations and is complicated by the great variety and heterogeneity of different experimentally observed states. The mechanistic relationship between oligomers and fibrils remains to be clarified, both in terms of assembly of oligomers into fibrils and potential dissolution of fibrils into oligomers. While oligomers are possibly implicated in the collapse of neuronal homeostasis, the fibrillar state(s) appears to be the most efficient at propagating itself both in vitro and in vivo, pointing to critical roles for multiple different aggregate species in the progression of Parkinson's disease (https://onlinelibrary.wiley.com/page/journal/14714159/homepage/virtual_issues.htm). This article is part of the Special Issue "Synuclein".
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Affiliation(s)
- Parvez Alam
- iNANO and Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Luc Bousset
- Institute Francois Jacob (MIRCen), CEA and Laboratory of Neurodegenerative Diseases, CNRS, Fontenay-Aux-Roses cedex, France
| | - Ronald Melki
- Institute Francois Jacob (MIRCen), CEA and Laboratory of Neurodegenerative Diseases, CNRS, Fontenay-Aux-Roses cedex, France
| | - Daniel E Otzen
- iNANO and Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
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154
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Yeboah F, Kim TE, Bill A, Dettmer U. Dynamic behaviors of α-synuclein and tau in the cellular context: New mechanistic insights and therapeutic opportunities in neurodegeneration. Neurobiol Dis 2019; 132:104543. [PMID: 31351173 DOI: 10.1016/j.nbd.2019.104543] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/18/2019] [Accepted: 07/22/2019] [Indexed: 10/26/2022] Open
Abstract
α-Synuclein (αS) and tau have a lot in common. Dyshomeostasis and aggregation of both proteins are central in the pathogenesis of neurodegenerative diseases: Parkinson's disease, dementia with Lewy bodies, multi-system atrophy and other 'synucleinopathies' in the case of αS; Alzheimer's disease, frontotemporal dementia, progressive supranuclear palsy and other 'tauopathies' in the case of tau. The aggregated states of αS and tau are found to be (hyper)phosphorylated, but the relevance of the phosphorylation in health or disease is not well understood. Both tau and αS are typically characterized as 'intrinsically disordered' proteins, while both engage in transient interactions with cellular components, thereby undergoing structural changes and context-specific folding. αS transiently binds to (synaptic) vesicles forming a membrane-induced amphipathic helix; tau transiently interacts with microtubules forming an 'extended structure'. The regulation and exact nature of the interactions are not fully understood. Here we review recent and previous insights into the dynamic, transient nature of αS and tau with regard to the mode of interaction with their targets, the dwell-time while bound, and the cis and trans factors underlying the frequent switching between bound and unbound states. These aspects are intimately linked to hypotheses on how subtle changes in the transient behaviors may trigger the earliest steps in the pathogenesis of the respective brain diseases. Based on a deeper understanding of transient αS and tau conformations in the cellular context, new therapeutic strategies may emerge, and it may become clearer why existing approaches have failed or how they could be optimized.
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Affiliation(s)
- Fred Yeboah
- Novartis Institute for Biomedical Research, Chemical Biology and Therapeutics, Cambridge, MA 02139, USA
| | - Tae-Eun Kim
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Anke Bill
- Novartis Institute for Biomedical Research, Chemical Biology and Therapeutics, Cambridge, MA 02139, USA.
| | - Ulf Dettmer
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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155
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Hallett PJ, Engelender S, Isacson O. Lipid and immune abnormalities causing age-dependent neurodegeneration and Parkinson's disease. J Neuroinflammation 2019; 16:153. [PMID: 31331333 PMCID: PMC6647317 DOI: 10.1186/s12974-019-1532-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 06/25/2019] [Indexed: 12/31/2022] Open
Abstract
This article describes pathogenic concepts and factors, in particular glycolipid abnormalities, that create cell dysfunction and synaptic loss in neurodegenerative diseases. By phenocopying lysosomal storage disorders, such as Gaucher disease and related disorders, age- and dose-dependent changes in glycolipid cell metabolism can lead to Parkinson's disease and related dementias. Recent results show that perturbation of sphingolipid metabolism can precede or is a part of abnormal protein handling in both genetic and idiopathic Parkinson's disease and Lewy body dementia. In aging and genetic predisposition with lipid disturbance, α-synuclein's normal vesicular and synaptic role may be detrimentally shifted toward accommodating and binding such lipids. Specific neuronal glycolipid, protein, and vesicular interactions create potential pathophysiology that is amplified by astroglial and microglial immune mechanisms resulting in neurodegeneration. This perspective provides a new logic for therapeutic interventions that do not focus on protein aggregation, but rather provides a guide to the complex biology and the common sequence of events that lead to age-dependent neurodegenerative disorders.
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Affiliation(s)
- Penelope J Hallett
- Neuroregeneration Research Institute, McLean Hospital/Harvard Medical School, Boston, USA
| | - Simone Engelender
- Neuroregeneration Research Institute, McLean Hospital/Harvard Medical School, Boston, USA.,Present Address: Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, 31096, Haifa, Israel
| | - Ole Isacson
- Neuroregeneration Research Institute, McLean Hospital/Harvard Medical School, Boston, USA.
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156
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Abstract
Biomarker discovery and validation are necessary for improving the prediction of clinical outcomes and patient monitoring. Despite considerable interest in biomarker discovery and development, improvements in the range and quality of biomarkers are still needed. The main challenge is how to integrate preclinical data to obtain a reliable biomarker that can be measured with acceptable costs in routine clinical practice. Epigenetic alterations are already being incorporated as valuable candidates in the biomarker field. Furthermore, their reversible nature offers a promising opportunity to ameliorate disease symptoms by using epigenetic-based therapy. Thus, beyond helping to understand disease biology, clinical epigenetics is being incorporated into patient management in oncology, as well as being explored for clinical applicability for other human pathologies such as neurological and infectious diseases and immune system disorders.
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157
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Karpowicz RJ, Trojanowski JQ, Lee VMY. Transmission of α-synuclein seeds in neurodegenerative disease: recent developments. J Transl Med 2019; 99:971-981. [PMID: 30760864 PMCID: PMC6609465 DOI: 10.1038/s41374-019-0195-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 11/19/2018] [Indexed: 12/18/2022] Open
Abstract
Cell-to-cell transmission of proteopathic alpha-synuclein (α-syn) seeds is increasingly thought to underlie the progression of neurodegenerative diseases including Parkinson's disease, dementia with Lewy bodies, multiple system atrophy, and related synucleinopathies. As such, it is important to understand the chemical and biological relationships between cells and pathological aggregates of α-syn. This brief review updates our understanding of the templated spread of α-syn pathology in neurodegenerative disease from the perspective of proteopathic α-syn seeds, including how these seeds are processed by cells as well as their effects on cellular function. Recent advances in understanding the conformations of α-syn seeds are highlighted, and the possible structural basis for the observed heterogeneity of synucleinopathies is discussed. Finally, we propose the possibility that some known risk factors for synucleinopathies may in fact potentiate the cell-to-cell transmission of α-syn pathology via imbalances in interrelated cell biological processes.
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Affiliation(s)
- Richard J. Karpowicz
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - John Q. Trojanowski
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Virginia M.-Y. Lee
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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158
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Ramezani M, Wilkes MM, Das T, Holowka D, Eliezer D, Baird B. Regulation of exocytosis and mitochondrial relocalization by Alpha-synuclein in a mammalian cell model. NPJ PARKINSONS DISEASE 2019; 5:12. [PMID: 31263746 PMCID: PMC6597712 DOI: 10.1038/s41531-019-0084-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 05/23/2019] [Indexed: 12/24/2022]
Abstract
We characterized phenotypes in RBL-2H3 mast cells transfected with human alpha synuclein (a-syn) using stimulated exocytosis of recycling endosomes as a proxy for similar activities of synaptic vesicles in neurons. We found that low expression of a-syn inhibits stimulated exocytosis and that higher expression causes slight enhancement. NMR measurements of membrane interactions correlate with these functional effects: they are eliminated differentially by mutants that perturb helical structure in the helix 1 (A30P) or NAC/helix-2 (V70P) regions of membrane-bound a-syn, but not by other PD-associated mutants or C-terminal truncation. We further found that a-syn (but not A30P or V70P mutants) associates weakly with mitochondria, but this association increases markedly under conditions of cellular stress. These results highlight the importance of specific structural features of a-syn in regulating vesicle release, and point to a potential role for a-syn in perturbing mitochondrial function under pathological conditions.
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Affiliation(s)
- Meraj Ramezani
- 1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 USA
| | - Marcus M Wilkes
- 1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 USA
| | - Tapojyoti Das
- 2Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065 USA
| | - David Holowka
- 1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 USA
| | - David Eliezer
- 2Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065 USA
| | - Barbara Baird
- 1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 USA
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159
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Twohig D, Nielsen HM. α-synuclein in the pathophysiology of Alzheimer's disease. Mol Neurodegener 2019; 14:23. [PMID: 31186026 PMCID: PMC6558879 DOI: 10.1186/s13024-019-0320-x] [Citation(s) in RCA: 190] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 04/26/2019] [Indexed: 02/07/2023] Open
Abstract
The Alzheimer’s disease (AD) afflicted brain is neuropathologically defined by extracellular amyloid-β (Aβ) plaques and intraneuronal neurofibrillary tangles composed of hyperphosphorylated tau protein. However, accumulating evidence suggests that the presynaptic protein α-synuclein (αSyn), mainly associated with synucleinopathies like Parkinson’s disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA), is involved in the pathophysiology of AD. Lewy-related pathology (LRP), primarily comprised of αSyn, is present in a majority of autopsied AD brains, and higher levels of αSyn in the cerebrospinal fluid (CSF) of patients with mild cognitive impairment (MCI) and AD have been linked to cognitive decline. Recent studies also suggest that the asymptomatic accumulation of Aβ plaques is associated with higher CSF αSyn levels in subjects at risk of sporadic AD and in individuals carrying autosomal dominant AD mutations. Experimental evidence has further linked αSyn mainly to tau hyperphosphorylation, but also to the pathological actions of Aβ and the APOEε4 allele, the latter being a major genetic risk factor for both AD and DLB. In this review, we provide a summary of the current evidence proposing an involvement of αSyn either as an active or passive player in the pathophysiological ensemble of AD, and furthermore describe in detail the current knowledge of αSyn structure and inferred function.
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Affiliation(s)
- Daniel Twohig
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius Väg 16B, 10691, Stockholm, Sweden
| | - Henrietta M Nielsen
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius Väg 16B, 10691, Stockholm, Sweden.
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160
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Silm K, Yang J, Marcott PF, Asensio CS, Eriksen J, Guthrie DA, Newman AH, Ford CP, Edwards RH. Synaptic Vesicle Recycling Pathway Determines Neurotransmitter Content and Release Properties. Neuron 2019; 102:786-800.e5. [PMID: 31003725 PMCID: PMC6541489 DOI: 10.1016/j.neuron.2019.03.031] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 01/28/2019] [Accepted: 03/19/2019] [Indexed: 01/03/2023]
Abstract
In contrast to temporal coding by synaptically acting neurotransmitters such as glutamate, neuromodulators such as monoamines signal changes in firing rate. The two modes of signaling have been thought to reflect differences in release by different cells. We now find that midbrain dopamine neurons release glutamate and dopamine with different properties that reflect storage in different synaptic vesicles. The vesicles differ in release probability, coupling to presynaptic Ca2+ channels and frequency dependence. Although previous work has attributed variation in these properties to differences in location or cytoskeletal association of synaptic vesicles, the release of different transmitters shows that intrinsic differences in vesicle identity drive different modes of release. Indeed, dopamine but not glutamate vesicles depend on the adaptor protein AP-3, revealing an unrecognized linkage between the pathway of synaptic vesicle recycling and the properties of exocytosis. Storage of the two transmitters in different vesicles enables the transmission of distinct signals.
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Affiliation(s)
- Kätlin Silm
- Departments of Neurology and Physiology, Graduate Programs in Neuroscience and Cell Biology, Kavli Institute for Fundamental Neuroscience, Weill Institute for the Neurosciences, UCSF School of Medicine, San Francisco, CA 94143, USA
| | - Jing Yang
- Departments of Neurology and Physiology, Graduate Programs in Neuroscience and Cell Biology, Kavli Institute for Fundamental Neuroscience, Weill Institute for the Neurosciences, UCSF School of Medicine, San Francisco, CA 94143, USA
| | - Pamela F Marcott
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Cedric S Asensio
- Departments of Neurology and Physiology, Graduate Programs in Neuroscience and Cell Biology, Kavli Institute for Fundamental Neuroscience, Weill Institute for the Neurosciences, UCSF School of Medicine, San Francisco, CA 94143, USA
| | - Jacob Eriksen
- Departments of Neurology and Physiology, Graduate Programs in Neuroscience and Cell Biology, Kavli Institute for Fundamental Neuroscience, Weill Institute for the Neurosciences, UCSF School of Medicine, San Francisco, CA 94143, USA
| | - Daryl A Guthrie
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institutes of Drug Abuse - Intramural Research Program, Baltimore, MD 21224, USA
| | - Amy H Newman
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institutes of Drug Abuse - Intramural Research Program, Baltimore, MD 21224, USA
| | - Christopher P Ford
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Robert H Edwards
- Departments of Neurology and Physiology, Graduate Programs in Neuroscience and Cell Biology, Kavli Institute for Fundamental Neuroscience, Weill Institute for the Neurosciences, UCSF School of Medicine, San Francisco, CA 94143, USA.
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161
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Guček A, Gandasi NR, Omar-Hmeadi M, Bakke M, Døskeland SO, Tengholm A, Barg S. Fusion pore regulation by cAMP/Epac2 controls cargo release during insulin exocytosis. eLife 2019; 8:41711. [PMID: 31099751 PMCID: PMC6557626 DOI: 10.7554/elife.41711] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 04/28/2019] [Indexed: 12/20/2022] Open
Abstract
Regulated exocytosis establishes a narrow fusion pore as initial aqueous connection to the extracellular space, through which small transmitter molecules such as ATP can exit. Co-release of polypeptides and hormones like insulin requires further expansion of the pore. There is evidence that pore expansion is regulated and can fail in diabetes and neurodegenerative disease. Here, we report that the cAMP-sensor Epac2 (Rap-GEF4) controls fusion pore behavior by acutely recruiting two pore-restricting proteins, amisyn and dynamin-1, to the exocytosis site in insulin-secreting beta-cells. cAMP elevation restricts and slows fusion pore expansion and peptide release, but not when Epac2 is inactivated pharmacologically or in Epac2-/- (Rapgef4-/-) mice. Consistently, overexpression of Epac2 impedes pore expansion. Widely used antidiabetic drugs (GLP-1 receptor agonists and sulfonylureas) activate this pathway and thereby paradoxically restrict hormone release. We conclude that Epac2/cAMP controls fusion pore expansion and thus the balance of hormone and transmitter release during insulin granule exocytosis. Insulin is the hormone that signals to the body to take up sugar from the blood. Specialized cells in the pancreas – known as β-cells – release insulin after a meal. Before that, insulin molecules are stored in tiny granules inside the β-cells; these granules must fuse with the cells’ surface membranes to release their contents. The first step in this process creates a narrow pore that allows small molecules, but not the larger insulin molecules, to seep out. The pore then widens to release the insulin. Since the small molecules are known to act locally in the pancreas, it is possible that this “molecular sieve” is biologically important. Yet it is not clear how the pore widens. One of the problems for people with type 2 diabetes is that they release less insulin into the bloodstream. Two kinds of drugs used to treat these patients work by stimulating β-cells to release their insulin. One way to achieve this is by raising the levels of a small molecule called cAMP, which is well known to help prepare insulin granules for release. The cAMP molecule also seems to slow the widening of the pore, and Gucek et al. have now investigated how this happens at a molecular level. By observing individual granules of human β-cells using a special microscope, Gucek et al. could watch how different drugs affect pore widening and content release. They also saw that cAMP activated a protein called Epac2, which then recruited two other proteins – amisyn and dynamin – to the small pores. These two proteins together then closed the pore, rather than expanding it to let insulin out. Type 2 diabetes patients sometimes have high levels of amisyn in their β-cells, which could explain why they do not release enough insulin. The microscopy experiments also revealed that two common anti-diabetic drugs activate Epac2 and prevent the pores from widening, thereby counteracting their positive effect on insulin release. The combined effect is likely a shift in the balance between insulin and the locally acting small molecules. These findings suggest that two common anti-diabetic drugs activate a common mechanism that may lead to unexpected outcomes, possibly even reducing how much insulin the β-cells can release. Future studies in mice and humans will have to investigate these effects in whole organisms.
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Affiliation(s)
- Alenka Guček
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Nikhil R Gandasi
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | | | - Marit Bakke
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Anders Tengholm
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Sebastian Barg
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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162
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Selkoe DJ. Showing transmitters the door: synucleins accelerate vesicle release. Nat Neurosci 2019; 20:629-631. [PMID: 28440807 DOI: 10.1038/nn.4551] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Dennis J Selkoe
- Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts, USA
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163
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α-Synuclein (αSyn) Preformed Fibrils Induce Endogenous αSyn Aggregation, Compromise Synaptic Activity and Enhance Synapse Loss in Cultured Excitatory Hippocampal Neurons. J Neurosci 2019; 39:5080-5094. [PMID: 31036761 DOI: 10.1523/jneurosci.0060-19.2019] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/16/2019] [Accepted: 04/20/2019] [Indexed: 12/22/2022] Open
Abstract
Synucleinopathies are characterized by the accumulation of insoluble α-synuclein (αSyn). To test whether αSyn aggregates modulate synaptic activity, we used a recently developed model in primary neurons for inducing αSyn pathology. We demonstrated that preformed fibrils (PFFs) generated with recombinant human αSyn compromised synaptic activity in a time- and dose-dependent manner and that the magnitude of these deficits correlated with the formation of αSyn pathology in cultured excitatory hippocampal neurons from both sexes of mice. Remarkably, acute passive infusion of αSyn PFFs from whole-cell patch-clamp pipette decreased mEPSC frequency within 10 min followed by induction of αSyn pathology within 1 d. Moreover, by direct addition of αSyn PFFs into culture medium, the formation of misfolded αSyn inclusions dramatically compromised the colocalization of synaptic markers and altered dynamic changes of dendritic spines, but the viability of neurons was not affected up to 7 d post-treatment with αSyn PFFs. Our data indicate that intraneuronal αSyn fibrils impaired the initiation of synaptogenesis and their physiological functions, thereby suggesting that targeting synaptic dysfunction in synucleinopathies may provide a promising therapeutic direction.SIGNIFICANCE STATEMENT Under pathological conditions, the presynaptic protein α-synuclein (αSyn) aggregates to form intraneuronal inclusions. To understand how and to what extent αSyn aggregates modulate synaptic activity before neuron loss, we demonstrate that αSyn preformed fibrils (PFFs) reduced synaptic activity in a dose- and time-dependent manner. The magnitude of these deficits correlated with the deposition of αSyn pathology, which dramatically compromised the colocalization of synaptic markers and altered the dendritic spine dynamics. The present work further highlights the impact of αSyn PFFs on synaptogenesis and physiological function, which may be applicable to other types of synucleinopathies.
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164
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Tao J, Bulgari D, Berkhoudt DA, Calderon MJ, Watkins SC, Fonseca Velez HJ, Sabeva N, Deitcher DL, Levitan ES. Drosophila Ptp4E regulates vesicular packaging for monoamine-neuropeptide co-transmission. J Cell Sci 2019; 132:jcs.224568. [PMID: 30837287 DOI: 10.1242/jcs.224568] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 02/25/2019] [Indexed: 12/12/2022] Open
Abstract
Many neurons influence their targets through co-release of neuropeptides and small-molecule transmitters. Neuropeptides are packaged into dense-core vesicles (DCVs) in the soma and then transported to synapses, while small-molecule transmitters such as monoamines are packaged by vesicular transporters that function at synapses. These separate packaging mechanisms point to activity, by inducing co-release as the sole scaler of co-transmission. Based on screening in Drosophila for increased presynaptic neuropeptides, the receptor protein tyrosine phosphatase (Rptp) Ptp4E was found to post-transcriptionally regulate neuropeptide content in single DCVs at octopamine synapses. This occurs without changing neuropeptide release efficiency, transport and DCV size measured by both stimulated emission depletion super-resolution and transmission electron microscopy. Ptp4E also controls the presynaptic abundance and activity of the vesicular monoamine transporter (VMAT), which packages monoamine transmitters for synaptic release. Thus, rather than rely on altering electrical activity, the Rptp regulates packaging underlying monoamine-neuropeptide co-transmission by controlling vesicular membrane transporter and luminal neuropeptide content.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Juan Tao
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Dinara Bulgari
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Drew A Berkhoudt
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Michael J Calderon
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Simon C Watkins
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Hector J Fonseca Velez
- Department of Neuroscience, Universidad Central del Caribe, Bayamón, Puerto Rico 00960, USA
| | - Nadezhda Sabeva
- Department of Neuroscience, Universidad Central del Caribe, Bayamón, Puerto Rico 00960, USA
| | - David L Deitcher
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Edwin S Levitan
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
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165
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Hawk BJD, Khounlo R, Shin YK. Alpha-Synuclein Continues to Enhance SNARE-Dependent Vesicle Docking at Exorbitant Concentrations. Front Neurosci 2019; 13:216. [PMID: 30949020 PMCID: PMC6437117 DOI: 10.3389/fnins.2019.00216] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 02/25/2019] [Indexed: 11/18/2022] Open
Abstract
Recently, Parkinson’s disease-associated α-synuclein (αS) has emerged as an important regulator for SNARE-dependent vesicle fusion. However, it is controversial if excessive accumulation of αS, even in the absence of aggregation, impairs neurotransmission. Here we use a single vesicle fusion assay with ms time resolution capable of dissecting the impact of αS on each step of membrane fusion. Unlike the previous results from various in vitro, cellular, and in vivo studies, we find that non-aggregated αS promotes vesicle merger even at exorbitant concentrations. The enhancement has been seen as much as 13 fold. Delving into the kinetics of the intermediate states for vesicle fusion reveals that αS stimulates vesicle docking without altering the dynamics of bilayer merger (lipid mixing). However, minute amounts of soluble aggregated species abolish SNARE-dependent bilayer merger completely. Thus, the results show that excessive accumulation of non-aggregated αS may not be toxic for neurotransmitter release.
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Affiliation(s)
- Brenden J D Hawk
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
| | - Ryan Khounlo
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
| | - Yeon-Kyun Shin
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
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166
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Sgobio C, Sun L, Ding J, Herms J, Lovinger DM, Cai H. Unbalanced calcium channel activity underlies selective vulnerability of nigrostriatal dopaminergic terminals in Parkinsonian mice. Sci Rep 2019; 9:4857. [PMID: 30890737 PMCID: PMC6425036 DOI: 10.1038/s41598-019-41091-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 02/18/2019] [Indexed: 11/23/2022] Open
Abstract
Dopamine (DA) release in striatum is functionally segregated across a dorsolateral/ventromedial axis. Interestingly, nigrostriatal DA signaling disruption in Parkinson's disease (PD) preferentially affects the dorsolateral striatum. The relationship between afferent presynaptic calcium transients (PreCaTs) in DA terminals and DA release in dorsolateral (Caudato-Putamen, DLS) and ventromedial (Nucleus Accumbens Shell, VS) striatal subregions was examined by ex vivo real-time dual-recording in conditional transgenic mice expressing the calcium indicator protein GCaMP3. In DLS, minimal increases in cytosolic calcium trigger steep DA release while PreCaTs and DA release in VS both were proportional to the number of pulses in burst stimulation. Co-expressing α-synuclein with the Parkinson's disease (PD)-associated A53T mutation and GCaMP3 in midbrain DA neurons revealed augmented cytosolic steady state and activity-dependent intra-terminal calcium levels preferentially in DLS, as well as hyperactivation and enhanced expression of N-type calcium channels. Thus, unbalanced calcium channel activity is a presynaptic mechanism to consider in the multifaceted pathogenic pathways of progressive neurodegeneration.
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Affiliation(s)
- Carmelo Sgobio
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
- Translational research division, German Center for Neurodegenerative Diseases (DZNE), Munich, 81377, Germany
| | - Lixin Sun
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jinhui Ding
- Computational Biology Group, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jochen Herms
- Translational research division, German Center for Neurodegenerative Diseases (DZNE), Munich, 81377, Germany
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-Universität München, Munich, 81377, Germany
| | - David M Lovinger
- Laboratory for Integrative Neuroscience, Section on Synaptic Pharmacology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, 20852, USA.
| | - Huaibin Cai
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA.
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167
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Martinelli AHS, Lopes FC, John EBO, Carlini CR, Ligabue-Braun R. Modulation of Disordered Proteins with a Focus on Neurodegenerative Diseases and Other Pathologies. Int J Mol Sci 2019; 20:ijms20061322. [PMID: 30875980 PMCID: PMC6471803 DOI: 10.3390/ijms20061322] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/03/2019] [Accepted: 02/12/2019] [Indexed: 12/15/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) do not have rigid 3D structures, showing changes in their folding depending on the environment or ligands. Intrinsically disordered proteins are widely spread in eukaryotic genomes, and these proteins participate in many cell regulatory metabolism processes. Some IDPs, when aberrantly folded, can be the cause of some diseases such as Alzheimer′s, Parkinson′s, and prionic, among others. In these diseases, there are modifications in parts of the protein or in its entirety. A common conformational variation of these IDPs is misfolding and aggregation, forming, for instance, neurotoxic amyloid plaques. In this review, we discuss some IDPs that are involved in neurodegenerative diseases (such as beta amyloid, alpha synuclein, tau, and the “IDP-like” PrP), cancer (p53, c-Myc), and diabetes (amylin), focusing on the structural changes of these IDPs that are linked to such pathologies. We also present the IDP modulation mechanisms that can be explored in new strategies for drug design. Lastly, we show some candidate drugs that can be used in the future for the treatment of diseases caused by misfolded IDPs, considering that cancer therapy has more advanced research in comparison to other diseases, while also discussing recent and future developments in this area of research. Therefore, we aim to provide support to the study of IDPs and their modulation mechanisms as promising approaches to combat such severe diseases.
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Affiliation(s)
- Anne H S Martinelli
- Department of Molecular Biology and Biotechnology & Department of Biophysics, Biosciences Institute-IB, (UFRGS), Porto Alegre CEP 91501-970, RS, Brazil.
| | - Fernanda C Lopes
- Center for Biotechnology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre CEP 91501-970, RS, Brazil.
- Graduate Program in Cell and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre CEP 91501-970, RS, Brazil.
| | - Elisa B O John
- Center for Biotechnology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre CEP 91501-970, RS, Brazil.
- Graduate Program in Cell and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre CEP 91501-970, RS, Brazil.
| | - Célia R Carlini
- Graduate Program in Cell and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre CEP 91501-970, RS, Brazil.
- Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre CEP 91410-000, RS, Brazil.
- Brain Institute-InsCer, Laboratory of Neurotoxins, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre CEP 90610-000, RS, Brazil.
| | - Rodrigo Ligabue-Braun
- Department of Pharmaceutical Sciences, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre CEP 90050-170, RS, Brazil.
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168
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Mor DE, Daniels MJ, Ischiropoulos H. The usual suspects, dopamine and alpha-synuclein, conspire to cause neurodegeneration. Mov Disord 2019; 34:167-179. [PMID: 30633814 PMCID: PMC6379109 DOI: 10.1002/mds.27607] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/15/2018] [Accepted: 12/03/2018] [Indexed: 01/07/2023] Open
Abstract
Parkinson's disease (PD) is primarily a movement disorder driven by the loss of dopamine-producing neurons in the substantia nigra (SN). Early identification of the oxidative properties of dopamine implicated it as a potential source of oxidative stress in PD, yet few studies have investigated dopamine neurotoxicity in vivo. The discovery of PD-causing mutations in α-synuclein and the presence of aggregated α-synuclein in the hallmark Lewy body pathology of PD revealed another important player. Despite extensive efforts, the precise role of α-synuclein aggregation in neurodegeneration remains unclear. We recently manipulated both dopamine levels and α-synuclein expression in aged mice and found that only the combination of these 2 factors caused progressive neurodegeneration of the SN and an associated motor deficit. Dopamine modified α-synuclein aggregation in the SN, resulting in greater abundance of α-synuclein oligomers and unique dopamine-induced oligomeric conformations. Furthermore, disruption of the dopamine-α-synuclein interaction rescued dopaminergic neurons from degeneration in transgenic Caenorhabditis elegans models. In this Perspective, we discuss these findings in the context of known α-synuclein and dopamine biology, review the evidence for α-synuclein oligomer toxicity and potential mechanisms, and discuss therapeutic implications. © 2019 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Danielle E. Mor
- Lewis-Sigler Institute for Integrative Genomics and Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Malcolm J. Daniels
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Harry Ischiropoulos
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Children’s Hospital of Philadelphia Research Institute, Philadelphia, PA, USA
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169
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Abbineni PS, Bohannon KP, Bittner MA, Axelrod D, Holz RW. Identification of β-synuclein on secretory granules in chromaffin cells and the effects of α- and β-synuclein on post-fusion BDNF discharge and fusion pore expansion. Neurosci Lett 2019; 699:134-139. [PMID: 30711526 DOI: 10.1016/j.neulet.2019.01.056] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 01/11/2019] [Accepted: 01/30/2019] [Indexed: 11/24/2022]
Abstract
α-Synuclein is strongly implicated in the pathogenesis of Parkinson's disease as well as in other neurodegenerative diseases. However, its normal function in cells is not understood. The N-termini of α-, β-, and γ-synuclein contains six to seven 11-amino acid repeats that are predicted to form amphipathic helices. Membrane-binding and membrane-curving abilities of synuclein raise the possibility that synuclein could alter cellular processes that involve highly curved structures. In the present study we examined the localization of endogenous synuclein in bovine chromaffin cells by immunocytochemistry and its possible function to control protein discharge upon fusion of the granule with the plasma membrane by regulating the fusion pore. We found with quantitative immunocytochemistry that endogenous β-synuclein associates with secretory granules. Endogenous α-synuclein only rarely co-localizes with secretory granules. Overexpression of α-synuclein but not β-synuclein quickened the post- fusion discharge of BDNF-pHluorin by approxinately 30%. However, neither α- nor β-synuclein significantly altered curvature dynamics associated with fusion pore expansion that were measured by the combination of polarization and total internal reflection fluorescence microscopy (pTIRFM). Whatever the mechanism, the physiological significance of the small increased rate of post-fusion protein discharge caused by α-synuclein remains to be demonstrated, especially since endogenous β-, but not α-synuclein is the predominant synuclein isoform associated with chromaffin granules.
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Affiliation(s)
- Prabhodh S Abbineni
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Kevin P Bohannon
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Mary A Bittner
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Daniel Axelrod
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States; Departments of Physics and LSA Biophysics, University of Michigan, Ann Arbor, MI, United States
| | - Ronald W Holz
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States.
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170
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Huang M, Wang B, Li X, Fu C, Wang C, Kang X. α-Synuclein: A Multifunctional Player in Exocytosis, Endocytosis, and Vesicle Recycling. Front Neurosci 2019; 13:28. [PMID: 30745863 PMCID: PMC6360911 DOI: 10.3389/fnins.2019.00028] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 01/14/2019] [Indexed: 11/22/2022] Open
Abstract
α-synuclein (α-Syn) is a presynaptic enriched protein involved in the pathogenesis of Parkinson’s disease. However, the physiological roles of α-Syn remain poorly understood. Recent studies have indicated a critical role of α-Syn in the sensing and generation of membrane curvature during vesicular exocytosis and endocytosis. It has been known to modulate the assembly of SNARE complex during exocytosis including vesicle docking, priming and fusion steps. Growing evidence suggests that α-Syn also plays critical roles in the endocytosis of synaptic vesicles. It also modulates the availability of releasable vesicles by promoting synaptic vesicles clustering. Here, we provide an overview of recent progresses in understanding the function of α-Syn in the regulation of exocytosis, endocytosis, and vesicle recycling under physiological and pathological conditions.
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Affiliation(s)
- Mingzhu Huang
- School of Life Sciences, Liaocheng University, Liaocheng, China.,Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Bianbian Wang
- School of Life Sciences, Liaocheng University, Liaocheng, China.,Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Xiaopeng Li
- School of Life Sciences, Liaocheng University, Liaocheng, China.,Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Chongluo Fu
- School of Life Sciences, Liaocheng University, Liaocheng, China
| | - Changhe Wang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Xinjiang Kang
- School of Life Sciences, Liaocheng University, Liaocheng, China.,Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
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171
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Living in Promiscuity: The Multiple Partners of Alpha-Synuclein at the Synapse in Physiology and Pathology. Int J Mol Sci 2019; 20:ijms20010141. [PMID: 30609739 PMCID: PMC6337145 DOI: 10.3390/ijms20010141] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 12/24/2018] [Accepted: 12/26/2018] [Indexed: 12/18/2022] Open
Abstract
Alpha-synuclein (α-syn) is a small protein that, in neurons, localizes predominantly to presynaptic terminals. Due to elevated conformational plasticity, which can be affected by environmental factors, in addition to undergoing disorder-to-order transition upon interaction with different interactants, α-syn is counted among the intrinsically disordered proteins (IDPs) family. As with many other IDPs, α-syn is considered a hub protein. This function is particularly relevant at synaptic sites, where α-syn is abundant and interacts with many partners, such as monoamine transporters, cytoskeletal components, lipid membranes, chaperones and synaptic vesicles (SV)-associated proteins. These protein–protein and protein–lipid membrane interactions are crucial for synaptic functional homeostasis, and alterations in α-syn can cause disruption of this complex network, and thus a failure of the synaptic machinery. Alterations of the synaptic environment or post-translational modification of α-syn can induce its misfolding, resulting in the formation of oligomers or fibrillary aggregates. These α-syn species are thought to play a pathological role in neurodegenerative disorders with α-syn deposits such as Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), which are referred to as synucleinopathies. Here, we aim at revising the complex and promiscuous role of α-syn at synaptic terminals in order to decipher whether α-syn molecular interactants may influence its conformational state, contributing to its aggregation, or whether they are just affected by it.
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172
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Barbut D, Stolzenberg E, Zasloff M. Gastrointestinal Immunity and Alpha-Synuclein. JOURNAL OF PARKINSON'S DISEASE 2019; 9:S313-S322. [PMID: 31594249 PMCID: PMC6839499 DOI: 10.3233/jpd-191702] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/09/2019] [Indexed: 12/20/2022]
Abstract
The gastrointestinal (GI) tract is equipped with robust immune defenses which protect the organism from infection. Enteric nerves are front and center in this defensive network, even in the most primitive organisms. Neuropeptides exhibit potent antimicrobial activity in the vicinity of the nerve and attract the innate and adaptive immune systems to help confine the invading agent. Alpha-synuclein (αS) has many biophysical characteristics of antimicrobial peptides and binds small vesicles such as those carrying endocytosed viruses. It is induced in nerve cells in response to viral and bacterial infections. It renders the nerve cell resistant to viral infection and propagation. It signals the immune system by attracting neutrophils and macrophages, and by activating dendritic cells. Most remarkably αS is trafficked to the central nervous system (CNS) conferring immunity in advance of an infection. Chronic GI infection or breakdown of the epithelial barrier can cause αS to accumulate and form neurotoxic aggregates. Overproduction of αS in the enteric nervous system (ENS) and its chronic trafficking to the CNS may damage nerves and lead to Parkinson's disease. Targeting the formation of αS aggregates in the ENS may therefore slow the progression of the disease.
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Affiliation(s)
| | | | - Michael Zasloff
- Enterin, Inc., Philadelphia, PA, USA
- MedStar Georgetown Transplant Institute, Georgetown University Medical Center, Washington, DC, USA
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173
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Breger LS, Fuzzati Armentero MT. Genetically engineered animal models of Parkinson's disease: From worm to rodent. Eur J Neurosci 2018; 49:533-560. [PMID: 30552719 DOI: 10.1111/ejn.14300] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 11/13/2018] [Accepted: 11/16/2018] [Indexed: 12/26/2022]
Abstract
Parkinson's disease (PD) is a progressive neurological disorder characterised by aberrant accumulation of insoluble proteins, including alpha-synuclein, and a loss of dopaminergic neurons in the substantia nigra. The extended neurodegeneration leads to a drop of striatal dopamine levels responsible for disabling motor and non-motor impairments. Although the causes of the disease remain unclear, it is well accepted among the scientific community that the disorder may also have a genetic component. For that reason, the number of genetically engineered animal models has greatly increased over the past two decades, ranging from invertebrates to more complex organisms such as mice and rats. This trend is growing as new genetic variants associated with the disease are discovered. The EU Joint Programme - Neurodegenerative Disease Research (JPND) has promoted the creation of an online database aiming at summarising the different features of experimental models of Parkinson's disease. This review discusses available genetic models of PD and the extent to which they adequately mirror the human pathology and reflects on future development and uses of genetically engineered experimental models for the study of PD.
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Affiliation(s)
- Ludivine S Breger
- Institut des Maladies Neurodégénératives, CNRS UMR 5293, Centre Broca Nouvelle Aquitaine, Université de Bordeaux, Bordeaux cedex, France
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174
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Korecka JA, Talbot S, Osborn TM, de Leeuw SM, Levy SA, Ferrari EJ, Moskites A, Atkinson E, Jodelka FM, Hinrich AJ, Hastings ML, Woolf CJ, Hallett PJ, Isacson O. Neurite Collapse and Altered ER Ca 2+ Control in Human Parkinson Disease Patient iPSC-Derived Neurons with LRRK2 G2019S Mutation. Stem Cell Reports 2018; 12:29-41. [PMID: 30595548 PMCID: PMC6335600 DOI: 10.1016/j.stemcr.2018.11.021] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 12/26/2022] Open
Abstract
The Parkinson disease (PD) genetic LRRK2 gain-of-function mutations may relate to the ER pathological changes seen in PD patients at postmortem. Human induced pluripotent stem cell (iPSC)-derived neurons with the PD pathogenic LRRK2 G2019S mutation exhibited neurite collapse when challenged with the ER Ca2+ influx sarco/ER Ca2+-ATPase inhibitor thapsigargin (THP). Baseline ER Ca2+ levels measured with the ER Ca2+ indicator CEPIA-ER were lower in LRRK2 G2019S human neurons, including in differentiated midbrain dopamine neurons in vitro. After THP challenge, PD patient-derived neurons displayed increased Ca2+ influx and decreased intracellular Ca2+ buffering upon membrane depolarization. These effects were reversed following LRRK2 mutation correction by antisense oligonucleotides and gene editing. Gene expression analysis in LRRK2 G2019S neurons identified modified levels of key store-operated Ca2+ entry regulators, with no alterations in ER Ca2+ efflux. These results demonstrate PD gene mutation LRRK2 G2019S ER calcium-dependent pathogenic effects in human neurons. Parkinson-linked LRRK2 G2019S induces neurite collapse upon ER Ca2+ influx block LRRK2 G2019S mutation alters Ca2+ uptake and buffering upon ER Ca2+ influx block The LRRK2 G2019S mutation decreases basal ER Ca2+ levels in human iPSC neurons The LRRK2 G2019S mutation modifies gene expression of key SOCE regulators
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Affiliation(s)
- Joanna A Korecka
- Neuroregeneration Research Institute, Harvard Medical School/McLean Hospital, Belmont, MA 02478, USA.
| | - Sebastien Talbot
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Teresia M Osborn
- Neuroregeneration Research Institute, Harvard Medical School/McLean Hospital, Belmont, MA 02478, USA
| | - Sherida M de Leeuw
- Neuroregeneration Research Institute, Harvard Medical School/McLean Hospital, Belmont, MA 02478, USA
| | - Simon A Levy
- Neuroregeneration Research Institute, Harvard Medical School/McLean Hospital, Belmont, MA 02478, USA
| | - Eliza J Ferrari
- Neuroregeneration Research Institute, Harvard Medical School/McLean Hospital, Belmont, MA 02478, USA
| | - Alyssa Moskites
- Neuroregeneration Research Institute, Harvard Medical School/McLean Hospital, Belmont, MA 02478, USA
| | - Elise Atkinson
- Neuroregeneration Research Institute, Harvard Medical School/McLean Hospital, Belmont, MA 02478, USA
| | - Francine M Jodelka
- Center for Genetics Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Anthony J Hinrich
- Center for Genetics Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Michelle L Hastings
- Center for Genetics Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Clifford J Woolf
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Penelope J Hallett
- Neuroregeneration Research Institute, Harvard Medical School/McLean Hospital, Belmont, MA 02478, USA
| | - Ole Isacson
- Neuroregeneration Research Institute, Harvard Medical School/McLean Hospital, Belmont, MA 02478, USA.
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175
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The Cellular Environment Affects Monomeric α-Synuclein Structure. Trends Biochem Sci 2018; 44:453-466. [PMID: 30527975 DOI: 10.1016/j.tibs.2018.11.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/13/2018] [Accepted: 11/16/2018] [Indexed: 12/19/2022]
Abstract
The presynaptic protein α-synuclein (aSyn) is an 'intrinsically disordered protein' that is highly dynamic in conformation. Transient intramolecular interactions between its charged N and C termini, and between its hydrophobic region and the C terminus, prevent self-association. These interactions inhibit the formation of insoluble inclusions, which are the pathological hallmark of Parkinson's disease and many other synucleinopathies. This review discusses how these intramolecular interactions are influenced by the specific environment aSyn is in. We discuss how charge, pH, calcium, and salt affect the physiological structure of monomeric aSyn, and how they may favour the formation of toxic structures. The more we understand the dynamic conformations of aSyn, the better we can design desperately needed therapeutics to prevent disease progression.
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176
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Huang CC, Chiu TY, Lee TY, Hsieh HJ, Lin CC, Kao LS. Soluble α-synuclein facilitates priming and fusion by releasing Ca 2+ from the thapsigargin-sensitive Ca 2+ pool in PC12 cells. J Cell Sci 2018; 131:jcs.213017. [PMID: 30404828 DOI: 10.1242/jcs.213017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 10/12/2018] [Indexed: 02/01/2023] Open
Abstract
α-Synuclein is associated with Parkinson's disease, and is mainly localized in presynaptic terminals and regulates exocytosis, but its physiological roles remain controversial. Here, we studied the effects of soluble and aggregated α-synuclein on exocytosis, and explored the molecular mechanism by which α-synuclein interacts with regulatory proteins, including Rab3A, Munc13-1 (also known as Unc13a) and Munc18-1 (also known as STXBP1), in order to regulate exocytosis. Through fluorescence recovery after photobleaching experiments, overexpressed α-synuclein in PC12 cells was found to be in a monomeric form, which promotes exocytosis. In contrast, aggregated α-synuclein induced by lactacystin treatment inhibits exocytosis. Our results show that α-synuclein is involved in vesicle priming and fusion. α-Synuclein and phorbol 12-myristate 13-acetate (PMA), which is known to enhance vesicle priming mediated by Rab3A, Munc13-1 and Munc18-1, act on the same population of vesicles, but regulate priming independently. Furthermore, the results show a novel effects of α-synuclein on mobilizing Ca2+ release from thapsigargin-sensitive Ca2+ pools to enhance the ATP-induced [Ca2+]i increase, which enhances vesicle fusion. Our results provide a detailed understanding of the action of α-synuclein during the final steps of exocytosis.
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Affiliation(s)
- Chien-Chang Huang
- Brain Research Center, National Yang-Ming University, Taipei 112, Taiwan, Republic of China.,Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan, Republic of China
| | - Tai-Yu Chiu
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan, Republic of China
| | - Tzu-Ying Lee
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan, Republic of China
| | - Hsin-Jui Hsieh
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan, Republic of China
| | - Chung-Chih Lin
- Brain Research Center, National Yang-Ming University, Taipei 112, Taiwan, Republic of China .,Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan, Republic of China.,Biophotonics Interdisciplinary Research Center, National Yang-Ming University, Taipei 112, Taiwan, Republic of China
| | - Lung-Sen Kao
- Brain Research Center, National Yang-Ming University, Taipei 112, Taiwan, Republic of China .,Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan, Republic of China
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177
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Yu C, Li CH, Chen S, Yoo H, Qin X, Park H. Decreased BDNF Release in Cortical Neurons of a Knock-in Mouse Model of Huntington's Disease. Sci Rep 2018; 8:16976. [PMID: 30451892 PMCID: PMC6242964 DOI: 10.1038/s41598-018-34883-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 10/27/2018] [Indexed: 01/18/2023] Open
Abstract
Huntington’s disease (HD) is a dominantly inherited neurodegenerative disease caused by an increase in CAG repeats in the Huntingtin gene (HTT). The striatum is one of the most vulnerable brain regions in HD, and altered delivery of BDNF to the striatum is believed to underlie this high vulnerability. However, the delivery of BDNF to the striatum in HD remains poorly understood. Here, we used real-time imaging to visualize release of BDNF from cortical neurons cultured alone or co-cultured with striatal neurons. BDNF release was significantly decreased in the cortical neurons of zQ175 mice (a knock-in model of HD), and total internal reflection fluorescence microscopy revealed several release patterns of single BDNF-containing vesicles, with distinct kinetics and prevalence, in co-cultured cortical HD neurons. Notably, a smaller proportion of single BDNF-containing vesicles underwent full release in HD neurons than in wild-type neurons. This decreased release of BDNF in cortical neurons might lead to decreased BDNF levels in the striatum because the striatum receives BDNF mainly from the cortex. In addition, we observed a decrease in the total travel length and speed of BDNF-containing vesicles in HD neurons, indicating altered transport of these vesicles in HD. Our findings suggest a potential mechanism for the vulnerability of striatal neurons in HD and offer new insights into the pathogenic mechanisms underlying the degeneration of neurons in HD.
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Affiliation(s)
- Chenglong Yu
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Chun Hei Li
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Sidong Chen
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Hanna Yoo
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xianan Qin
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Hyokeun Park
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. .,Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. .,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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178
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Melki R. Alpha-synuclein and the prion hypothesis in Parkinson's disease. Rev Neurol (Paris) 2018; 174:644-652. [DOI: 10.1016/j.neurol.2018.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/02/2018] [Accepted: 08/21/2018] [Indexed: 10/28/2022]
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179
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Brettschneider J, Suh E, Robinson JL, Fang L, Lee EB, Irwin DJ, Grossman M, Van Deerlin VM, Lee VMY, Trojanowski JQ. Converging Patterns of α-Synuclein Pathology in Multiple System Atrophy. J Neuropathol Exp Neurol 2018; 77. [PMID: 30203094 PMCID: PMC6181179 DOI: 10.1093/jnen/nly080#supplementary-data] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023] Open
Abstract
We aimed to determine patterns of α-synuclein (α-syn) pathology in multiple system atrophy (MSA) using 70-µm-thick sections of 20 regions of the central nervous system of 37 cases with striato-nigral degeneration (SND) and 10 cases with olivo-ponto-cerebellar atrophy (OPCA). In SND cases with the shortest disease duration (phase 1), α-syn pathology was observed in striatum, lentiform nucleus, substantia nigra, brainstem white matter tracts, cerebellar subcortical white matter as well as motor cortex, midfrontal cortex, and sensory cortex. SND with increasing duration of disease (phase 2) was characterized by involvement of spinal cord and thalamus, while phase 3 was characterized by involvement of hippocampus and amygdala. Cases with the longest disease duration (phase 4) showed involvement of the visual cortex. We observed an increasing overlap of α-syn pathology with increasing duration of disease between SND and OPCA, and noted increasingly similar regional distribution patterns of α-syn pathology. The GBA variant, p.Thr408Met, was found to have an allele frequency of 6.94% in SND cases which was significantly higher compared with normal (0%) and other neurodegenerative disease pathologies (0.74%), suggesting that it is associated with MSA. Our findings indicate that SND and OPCA show distinct early foci of α-syn aggregations, but increasingly converge with longer disease duration to show overlapping patterns of α-syn pathology.
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Affiliation(s)
- Johannes Brettschneider
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - EunRan Suh
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - John L Robinson
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Lubin Fang
- Clinical Neuroanatomy Section, Department of Neurology, Center for Biomedical Research, University of Ulm, Ulm, Germany
| | - Edward B Lee
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - David J Irwin
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Murray Grossman
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Vivianna M Van Deerlin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Virginia M -Y Lee
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - John Q Trojanowski
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
- Send correspondence to: John Q. Trojanowski, MD, PhD, CNDR, University of Pennsylvania School of Medicine, 3rd Floor Maloney Building, 3600 Spruce Street, Philadelphia, PA 19104; E-mail:
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180
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Presynaptic Dysfunction by Familial Factors in Parkinson Disease. Int Neurourol J 2018; 22:S115-121. [PMID: 30396260 PMCID: PMC6234725 DOI: 10.5213/inj.1836216.108] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 10/10/2018] [Indexed: 12/28/2022] Open
Abstract
Parkinson disease (PD) is the second most prevalent neurodegenerative disorder after Alzheimer disease. The loss of specific brain area, the substantia nigra pars compacta is known as a major etiology, however it is not fully understood how this neurodegeneration is initiated and what precisely causes this disease. As one aspect of pathophysiology for PD, synaptic dysfunction (synaptopathy) is thought to be an earlier appearance for neurodegeneration. In addition, some of the familial factors cumulatively exhibit that these factors such as α-synuclein, leucine-rich repeat kinase 2, parkin, PTEN-induced kinase 1, and DJ-1 are involved in the regulation of synaptic function and missense mutants of familial factors found in PD-patient show dysregulation of synaptic functions. In this review, we have discussed the physiological function of these genetic factors in presynaptic terminal and how dysregulation of presynaptic function by genetic factors might be related to the pathogenesis of Parkinson disease.
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181
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Taguchi K, Watanabe Y, Tsujimura A, Tanaka M. Expression of α-synuclein is regulated in a neuronal cell type-dependent manner. Anat Sci Int 2018; 94:11-22. [PMID: 30362073 PMCID: PMC6315015 DOI: 10.1007/s12565-018-0464-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 10/14/2018] [Indexed: 12/15/2022]
Abstract
α-Synuclein, the major component of Lewy bodies (LBs) and Lewy neurites (LNs), is expressed in presynapses under physiologically normal conditions and is involved in synaptic function. Abnormal intracellular aggregates of misfolded α-synuclein such as LBs and LNs are pathological hallmarks of synucleinopathies, including Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). According to previous studies using pathological models overexpressing α-synuclein, high expression of this protein in neurons is a critical risk factor for neurodegeneration. Therefore, it is important to know the endogenous expression levels of α-synuclein in each neuronal cell type. We previously reported differential expression profiles of α-synuclein in vitro and in vivo. In the wild-type mouse brain, particularly in vulnerable regions affected during the progression of idiopathic PD, α-synuclein is highly expressed in neuronal cell bodies of some early PD-affected regions, such as the olfactory bulb, the dorsal motor nucleus of the vagus, and the substantia nigra pars compacta. Synaptic expression of α-synuclein is mostly accompanied by expression of vesicular glutamate transporter-1, an excitatory synapse marker protein. In contrast, α-synuclein expression in inhibitory synapses differs among brain regions. Recently accumulated evidence indicates the close relationship between differential expression profiles of α-synuclein and selective vulnerability of certain neuronal populations. Further studies on the regulation of α-synuclein expression will help to understand the mechanism of LB pathology and provide an innovative therapeutic strategy to prevent PD and DLB onset.
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Affiliation(s)
- Katsutoshi Taguchi
- Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyo-ku, Kyoto, 602-8566, Japan
| | - Yoshihisa Watanabe
- Department of Basic Geriatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyo-ku, Kyoto, 602-8566, Japan
| | - Atsushi Tsujimura
- Department of Basic Geriatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyo-ku, Kyoto, 602-8566, Japan
| | - Masaki Tanaka
- Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyo-ku, Kyoto, 602-8566, Japan.
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182
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Lipid-dependent deposition of alpha-synuclein and Tau on neuronal Secretogranin II-positive vesicular membranes with age. Sci Rep 2018; 8:15207. [PMID: 30315256 PMCID: PMC6185981 DOI: 10.1038/s41598-018-33474-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 09/30/2018] [Indexed: 01/03/2023] Open
Abstract
This report demonstrates insoluble alpha-synuclein (aSYN)+ aggregates in human sporadic Parkinson’s disease (PD) midbrain that are linearly correlated with loss of glucocerebrosidase (GCase) activity. To identify early protein-lipid interactions that coincide with loss of lipid homeostasis, an aging study was carried out in mice with age-dependent reductions in GCase function. The analysis identified aberrant lipid-association by aSYN and hyperphosphorylated Tau (pTau) in a specific subset of neurotransmitter-containing, Secretogranin II (SgII)+ large, dense-core vesicles (LDCVs) responsible for neurotransmission of dopamine and other monoamines. The lipid vesicle-accumulation was concurrent with loss of PSD-95 suggesting synaptic destabilization. aSYN overexpression in the absence of lipid deregulation did not recapitulate the abnormal association with SgII+ vesicles. These results show lipid-dependent changes occur with age in neuronal vesicular membrane compartments that accumulate lipid-stabilized aSYN and pTau.
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183
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Nuber S, Rajsombath M, Minakaki G, Winkler J, Müller CP, Ericsson M, Caldarone B, Dettmer U, Selkoe DJ. Abrogating Native α-Synuclein Tetramers in Mice Causes a L-DOPA-Responsive Motor Syndrome Closely Resembling Parkinson's Disease. Neuron 2018; 100:75-90.e5. [PMID: 30308173 PMCID: PMC6211795 DOI: 10.1016/j.neuron.2018.09.014] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/16/2018] [Accepted: 09/06/2018] [Indexed: 11/22/2022]
Abstract
α-Synuclein (αS) regulates vesicle exocytosis but forms insoluble deposits in Parkinson's disease (PD). Developing disease-modifying therapies requires animal models that reproduce cardinal features of PD. We recently described a previously unrecognized physiological form of αS, α-helical tetramers, and showed that familial PD-causing missense mutations shift tetramers to aggregation-prone monomers. Here, we generated mice expressing the fPD E46K mutation plus 2 homologous E→K mutations in adjacent KTKEGV motifs. This tetramer-abrogating mutant causes phenotypes similar to PD. αS monomers accumulate at membranes and form vesicle-rich inclusions. αS becomes insoluble, proteinase K-resistant, Ser129-phosphorylated, and C-terminally truncated, as in PD. These changes affect regions controlling motor behavior, including a decrease in nigrostriatal dopaminergic neurons. The outcome is a progressive motor syndrome including tremor and gait and limb deficits partially responsive to L-DOPA. This fully penetrant phenotype indicates that tetramers are required for normal αS homeostasis and that chronically shifting tetramers to monomers may result in PD, with attendant therapeutic implications.
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Affiliation(s)
- Silke Nuber
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Molly Rajsombath
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Georgia Minakaki
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-University (FAU), Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Jürgen Winkler
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-University (FAU), Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Christian P Müller
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University (FAU), Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Maria Ericsson
- Electron Microscopy Laboratory, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Barbara Caldarone
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; NeuroBehavior Laboratory, Harvard NeuroDiscovery Center, Harvard Medical School, Boston, MA 02115, USA
| | - Ulf Dettmer
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Dennis J Selkoe
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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184
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de Diego AMG, García AG. Altered exocytosis in chromaffin cells from mouse models of neurodegenerative diseases. Acta Physiol (Oxf) 2018; 224:e13090. [PMID: 29742321 DOI: 10.1111/apha.13090] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 04/19/2018] [Accepted: 04/25/2018] [Indexed: 12/26/2022]
Abstract
Chromaffin cells from the adrenal gland (CCs) have extensively been used to explore the molecular structure and function of the exocytotic machinery, neurotransmitter release and synaptic transmission. The CC is integrated in the sympathoadrenal axis that helps the body maintain homoeostasis during both routine life and in acute stress conditions. This function is exquisitely controlled by the cerebral cortex and the hypothalamus. We propose the hypothesis that damage undergone by the brain during neurodegenerative diseases is also affecting the neurosecretory function of adrenal medullary CCs. In this context, we review here the following themes: (i) How the discharge of catecholamines is centrally and peripherally regulated at the sympathoadrenal axis; (ii) which are the intricacies of the amperometric techniques used to study the quantal release of single-vesicle exocytotic events; (iii) which are the alterations of the exocytotic fusion pore so far reported, in CCs of mouse models of neurodegenerative diseases; (iv) how some proteins linked to neurodegenerative pathologies affect the kinetics of exocytotic events; (v) finally, we try to integrate available data into a hypothesis to explain how the centrally originated neurodegenerative diseases may alter the kinetics of single-vesicle exocytotic events in peripheral adrenal medullary CCs.
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Affiliation(s)
- A. M. García de Diego
- Instituto Teófilo Hernando; Universidad Autónoma de Madrid; Madrid Spain
- Instituto de Investigación Sanitaria; Hospital Universitario de la Princesa; Universidad Autónoma de Madrid; Madrid Spain
- DNS Neuroscience; Parque Científico de Madrid; Madrid Spain
| | - A. García García
- Instituto Teófilo Hernando; Universidad Autónoma de Madrid; Madrid Spain
- Instituto de Investigación Sanitaria; Hospital Universitario de la Princesa; Universidad Autónoma de Madrid; Madrid Spain
- DNS Neuroscience; Parque Científico de Madrid; Madrid Spain
- Departamento de Farmacología y Terapéutica; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
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185
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Dettmer U. Rationally Designed Variants of α-Synuclein Illuminate Its in vivo Structural Properties in Health and Disease. Front Neurosci 2018; 12:623. [PMID: 30319334 PMCID: PMC6167557 DOI: 10.3389/fnins.2018.00623] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/20/2018] [Indexed: 12/11/2022] Open
Abstract
α-Synuclein (αS) is a conserved and abundant neuronal protein with unusual structural properties. It appears to partition between folded and unstructured states as well as between membrane-bound and aqueously soluble states. In addition, a switch between monomeric and tetrameric/multimeric states has been observed recently. The precise composition, localization and abundance of the multimeric species are under study and remain unsettled. Yet to interfere with disease pathogenesis, we must dissect how small changes in αS homeostasis may give rise to Parkinson’s disease (PD), dementia with Lewy bodies (DLB) and other human synucleinopathies. Rationally designed αS point mutations that prevent the protein from populating all states within its normal folding repertoire have continued to be instrumental in bringing new insights into its biochemistry in vivo. This review summarizes biochemical and cell biological findings about αS homeostasis from different labs, with a special emphasis on intact-cell approaches that may preserve the complex, metastable native states of αS.
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Affiliation(s)
- Ulf Dettmer
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
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186
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Adams JW, Alvarez VE, Mez J, Huber BR, Tripodis Y, Xia W, Meng G, Kubilus CA, Cormier K, Kiernan PT, Daneshvar DH, Chua AS, Svirsky S, Nicks R, Abdolmohammadi B, Evers L, Solomon TM, Cherry JD, Aytan N, Mahar I, Devine S, Auerbach S, Alosco ML, Nowinski CJ, Kowall NW, Goldstein LE, Dwyer B, Katz DI, Cantu RC, Stern RA, Au R, McKee AC, Stein TD. Lewy Body Pathology and Chronic Traumatic Encephalopathy Associated With Contact Sports. J Neuropathol Exp Neurol 2018; 77:757-768. [PMID: 30053297 PMCID: PMC6097837 DOI: 10.1093/jnen/nly065] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Traumatic brain injury has been associated with increased risk of Parkinson disease and parkinsonism, and parkinsonism and Lewy body disease (LBD) can occur with chronic traumatic encephalopathy (CTE). To test whether contact sports and CTE are associated with LBD, we compared deceased contact sports athletes (n = 269) to cohorts from the community (n = 164) and the Boston University Alzheimer disease (AD) Center (n = 261). Participants with CTE and LBD were more likely to have β-amyloid deposition, dementia, and parkinsonism than CTE alone (p < 0.05). Traditional and hierarchical clustering showed a similar pattern of LBD distribution in CTE compared to LBD alone that was most frequently neocortical, limbic, or brainstem. In the community-based cohort, years of contact sports play were associated with neocortical LBD (OR = 1.30 per year, p = 0.012), and in a pooled analysis a threshold of >8 years of play best predicted neocortical LBD (ROC analysis, OR = 6.24, 95% CI = 1.5-25, p = 0.011), adjusting for age, sex, and APOE ɛ4 allele status. Clinically, dementia was significantly associated with neocortical LBD, CTE stage, and AD; parkinsonism was associated with LBD pathology but not CTE stage. Contact sports participation may increase risk of developing neocortical LBD, and increased LBD frequency may partially explain extrapyramidal motor symptoms sometimes observed in CTE.
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Affiliation(s)
- Jason W Adams
- Boston University Alzheimer’s Disease and CTE Center
| | - Victor E Alvarez
- Department of Neurology
- Framingham Heart Study, Boston University School of Medicine, Boston, MA
- VA Boston Healthcare System, Boston, MA
| | - Jesse Mez
- Department of Neurology
- Framingham Heart Study, Boston University School of Medicine, Boston, MA
| | | | - Yorghos Tripodis
- Boston University Alzheimer’s Disease and CTE Center
- Department of Biostatistics, Boston University School of Public Health, Boston, MA
| | - Weiming Xia
- Boston University Alzheimer’s Disease and CTE Center
- Department of Veterans Affairs Medical Center, Bedford, MA
| | - Gaoyuan Meng
- Boston University Alzheimer’s Disease and CTE Center
- VA Boston Healthcare System, Boston, MA
- Department of Veterans Affairs Medical Center, Bedford, MA
| | | | - Kerry Cormier
- Boston University Alzheimer’s Disease and CTE Center
| | | | | | - Alicia S Chua
- Boston University Alzheimer’s Disease and CTE Center
- Department of Biostatistics, Boston University School of Public Health, Boston, MA
| | - Sarah Svirsky
- Boston University Alzheimer’s Disease and CTE Center
| | - Raymond Nicks
- Boston University Alzheimer’s Disease and CTE Center
| | | | - Laney Evers
- Boston University Alzheimer’s Disease and CTE Center
| | | | | | | | | | - Sherral Devine
- Department of Neurology
- Framingham Heart Study, Boston University School of Medicine, Boston, MA
| | - Sanford Auerbach
- Department of Neurology
- Framingham Heart Study, Boston University School of Medicine, Boston, MA
| | - Michael L Alosco
- Department of Neurology
- Framingham Heart Study, Boston University School of Medicine, Boston, MA
| | | | - Neil W Kowall
- Department of Neurology
- VA Boston Healthcare System, Boston, MA
| | - Lee E Goldstein
- Boston University Alzheimer’s Disease and CTE Center
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA
| | - Brigid Dwyer
- Department of Neurology
- Brain Injury Program, Braintree Rehabilitation Hospital, Braintree, MA
| | - Douglas I Katz
- Department of Neurology
- Brain Injury Program, Braintree Rehabilitation Hospital, Braintree, MA
| | - Robert C Cantu
- Boston University Alzheimer’s Disease and CTE Center
- Concussion Legacy Foundation
- Department of Anatomy and Neurobiology
- Department of Neurosurgery, Boston University School of Medicine, Boston, MA
- Department of Neurosurgery, Emerson Hospital, Concord, MA
| | - Robert A Stern
- Department of Neurology
- Department of Anatomy and Neurobiology
- Department of Neurosurgery, Boston University School of Medicine, Boston, MA
| | - Rhoda Au
- Department of Neurology
- Framingham Heart Study, Boston University School of Medicine, Boston, MA
- Department of Biostatistics, Boston University School of Public Health, Boston, MA
- Department of Epidemiology, Boston University School of Public Health, Boston, MA
| | - Ann C McKee
- Department of Neurology
- Framingham Heart Study, Boston University School of Medicine, Boston, MA
- VA Boston Healthcare System, Boston, MA
- Department of Veterans Affairs Medical Center, Bedford, MA
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA
| | - Thor D Stein
- Boston University Alzheimer’s Disease and CTE Center
- Framingham Heart Study, Boston University School of Medicine, Boston, MA
- VA Boston Healthcare System, Boston, MA
- Department of Veterans Affairs Medical Center, Bedford, MA
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA
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187
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Choi TS, Han JY, Heo CE, Lee SW, Kim HI. Electrostatic and hydrophobic interactions of lipid-associated α-synuclein: The role of a water-limited interfaces in amyloid fibrillation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1854-1862. [DOI: 10.1016/j.bbamem.2018.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 02/05/2018] [Accepted: 02/05/2018] [Indexed: 12/22/2022]
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188
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189
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Sharma S, Lindau M. The fusion pore, 60 years after the first cartoon. FEBS Lett 2018; 592:3542-3562. [PMID: 29904915 DOI: 10.1002/1873-3468.13160] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 06/07/2018] [Accepted: 06/12/2018] [Indexed: 11/10/2022]
Abstract
Neurotransmitter release occurs in the form of quantal events by fusion of secretory vesicles with the plasma membrane, and begins with the formation of a fusion pore that has a conductance similar to that of a large ion channel or gap junction. In this review, we propose mechanisms of fusion pore formation and discuss their implications for fusion pore structure and function. Accumulating evidence indicates a direct role of soluble N-ethylmaleimide-sensitive-factor attachment receptor proteins in the opening of fusion pores. Fusion pores are likely neither protein channels nor purely lipid, but are of proteolipidic composition. Future perspectives to gain better insight into the molecular structure of fusion pores are discussed.
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Affiliation(s)
- Satyan Sharma
- Laboratory for Nanoscale Cell Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Manfred Lindau
- Laboratory for Nanoscale Cell Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany.,School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
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190
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Inoshita T, Cui C, Hattori N, Imai Y. Regulation of membrane dynamics by Parkinson's disease-associated genes. J Genet 2018; 97:715-725. [PMID: 30027905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Parkinson's disease (PD), the second most common neurodegenerative disease after Alzheimer's disease, develops sporadically, and its cause is unknown. However, 5-10% of PD cases are inherited as monogenic diseases, which provides a chance to understand the molecular mechanisms underlying neurodegeneration. Over 20 causative genes have already been identified and are being characterized. These PD-associated genes are broadly classified into two groups: genes involved in mitochondrial functions and genes related to membrane dynamics such as intracellular vesicle transport and the lysosomal pathway. In this review, we summarize the latest findings on the mechanism by which members of the latter group of PD-associated genes regulate membrane dynamics, and we discuss how mutations of these genes lead to dopaminergic neurodegeneration.
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Affiliation(s)
- Tsuyoshi Inoshita
- Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.
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191
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Spillantini MG, Goedert M. Neurodegeneration and the ordered assembly of α-synuclein. Cell Tissue Res 2018; 373:137-148. [PMID: 29119326 PMCID: PMC6015613 DOI: 10.1007/s00441-017-2706-9] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 09/19/2017] [Indexed: 01/08/2023]
Abstract
In 2017, it was 200 years since James Parkinson published 'An Essay on the Shaking Palsy' and 20 years since α-synuclein aggregation came to the fore. In 1998, multiple system atrophy joined Parkinson's disease and dementia with Lewy bodies as the third major synucleinopathy. Here, we describe the work that led to the identification of α-synuclein in Lewy bodies, Lewy neurites and Papp-Lantos bodies. We also review some of the findings reported since 1997.
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Affiliation(s)
- Maria Grazia Spillantini
- Department of Clinical Neurosciences, Clifford Allbutt Building, University of Cambridge, Cambridge, UK.
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192
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Peelaerts W, Bousset L, Baekelandt V, Melki R. ɑ-Synuclein strains and seeding in Parkinson's disease, incidental Lewy body disease, dementia with Lewy bodies and multiple system atrophy: similarities and differences. Cell Tissue Res 2018; 373:195-212. [PMID: 29704213 DOI: 10.1007/s00441-018-2839-5] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 03/28/2018] [Indexed: 12/20/2022]
Abstract
Several age-related neurodegenerative disorders are characterized by the deposition of aberrantly folded endogenous proteins. These proteins have prion-like propagation and amplification properties but so far appear nontransmissible between individuals. Because of the features they share with the prion protein, PrP, the characteristics of pathogenic protein aggregates in several progressive brain disorders, including different types of Lewy body diseases (LBDs), such as Parkinson's disease (PD), multiple system atrophy (MSA) and dementia with Lewy bodies (DLB), have been actively investigated. Even though the pleomorphic nature of these syndromes might suggest different underlying causes, ɑ-synuclein (ɑSyn) appears to play an important role in this heterogeneous group of diseases (the synucleinopathies). An attractive hypothesis is that different types of ɑSyn protein assemblies have a unique and causative role in distinct synucleinopathies. We will discuss the recent research progress on ɑSyn assemblies involved in PD, MSA and DLB; their behavior as strains; current spreading hypotheses; their ability to seed centrally and peripherally; and their implication for disease pathogenesis.
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Affiliation(s)
- W Peelaerts
- Laboratory for Neurobiology and Gene Therapy, KU Leuven, 3000, Leuven, Belgium.,Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - L Bousset
- Paris-Saclay Institute of Neuroscience, CNRS, 91190, Gif-sur-Yvette, France
| | - V Baekelandt
- Laboratory for Neurobiology and Gene Therapy, KU Leuven, 3000, Leuven, Belgium.
| | - R Melki
- Paris-Saclay Institute of Neuroscience, CNRS, 91190, Gif-sur-Yvette, France
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193
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Weinshenker D. Long Road to Ruin: Noradrenergic Dysfunction in Neurodegenerative Disease. Trends Neurosci 2018; 41:211-223. [PMID: 29475564 PMCID: PMC5878728 DOI: 10.1016/j.tins.2018.01.010] [Citation(s) in RCA: 182] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/25/2018] [Accepted: 01/29/2018] [Indexed: 01/09/2023]
Abstract
It has been known for decades that degeneration of the locus coeruleus (LC), the major noradrenergic nucleus in the brain, occurs in both Alzheimer's disease (AD) and Parkinson's disease (PD), but it was given scant attention. It is now recognized that hyperphosphorylated tau in the LC is the first detectable AD-like neuropathology in the human brain, α-synuclein inclusions in the LC represent an early step in PD, and experimental LC lesions exacerbate neuropathology and cognitive/behavioral deficits in animal models. The purpose of this review is to consider the causes and consequences of LC pathology, dysfunction, and degeneration, as well as their implications for early detection and treatment.
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Affiliation(s)
- David Weinshenker
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA.
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194
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Barinova K, Khomyakova E, Semenyuk P, Schmalhausen E, Muronetz V. Binding of alpha-synuclein to partially oxidized glyceraldehyde-3-phosphate dehydrogenase induces subsequent inactivation of the enzyme. Arch Biochem Biophys 2018; 642:10-22. [DOI: 10.1016/j.abb.2018.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 01/15/2018] [Accepted: 02/03/2018] [Indexed: 12/23/2022]
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195
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Benskey MJ, Sellnow RC, Sandoval IM, Sortwell CE, Lipton JW, Manfredsson FP. Silencing Alpha Synuclein in Mature Nigral Neurons Results in Rapid Neuroinflammation and Subsequent Toxicity. Front Mol Neurosci 2018; 11:36. [PMID: 29497361 PMCID: PMC5819572 DOI: 10.3389/fnmol.2018.00036] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 01/26/2018] [Indexed: 12/19/2022] Open
Abstract
Human studies and preclinical models of Parkinson’s disease implicate the involvement of both the innate and adaptive immune systems in disease progression. Further, pro-inflammatory markers are highly enriched near neurons containing pathological forms of alpha synuclein (α-syn), and α-syn overexpression recapitulates neuroinflammatory changes in models of Parkinson’s disease. These data suggest that α-syn may initiate a pathological inflammatory response, however the mechanism by which α-syn initiates neuroinflammation is poorly understood. Silencing endogenous α-syn results in a similar pattern of nigral degeneration observed following α-syn overexpression. Here we aimed to test the hypothesis that loss of α-syn function within nigrostriatal neurons results in neuronal dysfunction, which subsequently stimulates neuroinflammation. Adeno-associated virus (AAV) expressing an short hairpin RNA (shRNA) targeting endogenous α-syn was unilaterally injected into the substantia nigra pars compacta (SNc) of adult rats, after which nigrostriatal pathology and indices of neuroinflammation were examined at 7, 10, 14 and 21 days post-surgery. Removing endogenous α-syn from nigrostriatal neurons resulted in a rapid up-regulation of the major histocompatibility complex class 1 (MHC-1) within transduced nigral neurons. Nigral MHC-1 expression occurred prior to any overt cell death and coincided with the recruitment of reactive microglia and T-cells to affected neurons. Following the induction of neuroinflammation, α-syn knockdown resulted in a 50% loss of nigrostriatal neurons in the SNc and a corresponding loss of nigrostriatal terminals and dopamine (DA) concentrations within the striatum. Expression of a control shRNA did not elicit any pathological changes. Silencing α-syn within glutamatergic neurons of the cerebellum did not elicit inflammation or cell death, suggesting that toxicity initiated by α-syn silencing is specific to DA neurons. These data provide evidence that loss of α-syn function within nigrostriatal neurons initiates a neuronal-mediated neuroinflammatory cascade, involving both the innate and adaptive immune systems, which ultimately results in the death of affected neurons.
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Affiliation(s)
- Matthew J Benskey
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
| | - Rhyomi C Sellnow
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
| | - Ivette M Sandoval
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States.,Mercy Health Saint Mary's, Grand Rapids, MI, United States
| | - Caryl E Sortwell
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States.,Mercy Health Saint Mary's, Grand Rapids, MI, United States
| | - Jack W Lipton
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States.,Mercy Health Saint Mary's, Grand Rapids, MI, United States
| | - Fredric P Manfredsson
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States.,Mercy Health Saint Mary's, Grand Rapids, MI, United States
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196
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GBA1 deficiency negatively affects physiological α-synuclein tetramers and related multimers. Proc Natl Acad Sci U S A 2018; 115:798-803. [PMID: 29311330 DOI: 10.1073/pnas.1700465115] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Accumulating evidence suggests that α-synuclein (α-syn) occurs physiologically as a helically folded tetramer that resists aggregation. However, the mechanisms underlying the regulation of formation of α-syn tetramers are still mostly unknown. Cellular membrane lipids are thought to play an important role in the regulation of α-syn tetramer formation. Since glucocerebrosidase 1 (GBA1) deficiency contributes to the aggregation of α-syn and leads to changes in neuronal glycosphingolipids (GSLs) including gangliosides, we hypothesized that GBA1 deficiency may affect the formation of α-syn tetramers. Here, we show that accumulation of GSLs due to GBA1 deficiency decreases α-syn tetramers and related multimers and increases α-syn monomers in CRISPR-GBA1 knockout (KO) SH-SY5Y cells. Moreover, α-syn tetramers and related multimers are decreased in N370S GBA1 Parkinson's disease (PD) induced pluripotent stem cell (iPSC)-derived human dopaminergic (hDA) neurons and murine neurons carrying the heterozygous L444P GBA1 mutation. Treatment with miglustat to reduce GSL accumulation and overexpression of GBA1 to augment GBA1 activity reverse the destabilization of α-syn tetramers and protect against α-syn preformed fibril-induced toxicity in hDA neurons. Taken together, these studies provide mechanistic insights into how GBA1 regulates the transition from monomeric α-syn to α-syn tetramers and multimers and suggest unique therapeutic opportunities for PD and dementia with Lewy bodies.
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197
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Nikoletopoulou V, Tavernarakis N. The PMR1 pump in alpha-synuclein toxicity and neurodegeneration. Neurosci Lett 2018; 663:66-71. [DOI: 10.1016/j.neulet.2017.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 07/26/2017] [Accepted: 08/01/2017] [Indexed: 12/14/2022]
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198
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Medeiros AT, Soll LG, Tessari I, Bubacco L, Morgan JR. α-Synuclein Dimers Impair Vesicle Fission during Clathrin-Mediated Synaptic Vesicle Recycling. Front Cell Neurosci 2017; 11:388. [PMID: 29321725 PMCID: PMC5732215 DOI: 10.3389/fncel.2017.00388] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 11/22/2017] [Indexed: 11/16/2022] Open
Abstract
α-Synuclein is a presynaptic protein that regulates synaptic vesicle (SV) trafficking. In Parkinson’s disease (PD) and several other neurodegenerative disorders, aberrant oligomerization and aggregation of α-synuclein lead to synaptic dysfunction and neurotoxicity. Despite evidence that α-synuclein oligomers are generated within neurons under physiological conditions, and that altering the balance of monomers and oligomers contributes to disease pathogenesis, how each molecular species of α-synuclein impacts SV trafficking is currently unknown. To address this, we have taken advantage of lamprey giant reticulospinal (RS) synapses, which are accessible to acute perturbations via axonal microinjection of recombinant proteins. We previously reported that acute introduction of monomeric α-synuclein inhibited SV recycling, including effects on the clathrin pathway. Here, we report the effects of α-synuclein dimers at synapses. Similar to monomeric α-synuclein, both recombinant α-synuclein dimers that were evaluated bound to small liposomes containing anionic lipids in vitro, but with reduced efficacy. When introduced to synapses, the α-synuclein dimers also induced SV recycling defects, which included a build up of clathrin-coated pits (CCPs) with constricted necks that were still attached to the plasma membrane, a phenotype indicative of a vesicle fission defect. Interestingly, both α-synuclein dimers induced longer necks on CCPs as well as complex, branching membrane tubules, which were distinct from the CCPs induced by a dynamin inhibitor, Dynasore. In contrast, monomeric α-synuclein induced a buildup of free clathrin-coated vesicles (CCVs), indicating an inhibition of clathrin-mediated endocytosis at a later stage during the clathrin uncoating process. Taken together, these data further support the conclusion that excess α-synuclein impairs SV recycling. The data additionally reveal that monomeric and dimeric α-synuclein produce distinct effects on clathrin-mediated endocytosis, predicting different molecular mechanisms. Understanding what these mechanisms are could help to further elucidate the normal functions of this protein, as well as the mechanisms underlying PD pathologies.
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Affiliation(s)
- Audrey T Medeiros
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Lindsey G Soll
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States
| | | | - Luigi Bubacco
- Department of Biology, University of Padova, Padova, Italy
| | - Jennifer R Morgan
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States
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199
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Whittaker HT, Qui Y, Bettencourt C, Houlden H. Multiple system atrophy: genetic risks and alpha-synuclein mutations. F1000Res 2017; 6:2072. [PMID: 29225795 PMCID: PMC5710304 DOI: 10.12688/f1000research.12193.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/22/2017] [Indexed: 12/28/2022] Open
Abstract
Multiple system atrophy (MSA) is one of the few neurodegenerative disorders where we have a significant understanding of the clinical and pathological manifestations but where the aetiology remains almost completely unknown. Research to overcome this hurdle is gaining momentum through international research collaboration and a series of genetic and molecular discoveries in the last few years, which have advanced our knowledge of this rare synucleinopathy. In MSA, the discovery of α-synuclein pathology and glial cytoplasmic inclusions remain the most significant findings. Families with certain types of α-synuclein mutations develop diseases that mimic MSA, and the spectrum of clinical and pathological features in these families suggests a spectrum of severity, from late-onset Parkinson's disease to MSA. Nonetheless, controversies persist, such as the role of common α-synuclein variants in MSA and whether this disorder shares a common mechanism of spreading pathology with other protein misfolding neurodegenerative diseases. Here, we review these issues, specifically focusing on α-synuclein mutations.
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Affiliation(s)
- Heather T Whittaker
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Yichen Qui
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Conceição Bettencourt
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK.,Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK.,MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK.,Neurogenetics Laboratory, The National Hospital for Neurology and Neurosurgery, London, UK
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200
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Brundin P, Dave KD, Kordower JH. Therapeutic approaches to target alpha-synuclein pathology. Exp Neurol 2017; 298:225-235. [PMID: 28987463 DOI: 10.1016/j.expneurol.2017.10.003] [Citation(s) in RCA: 167] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/26/2017] [Accepted: 10/03/2017] [Indexed: 01/09/2023]
Abstract
Starting two decades ago with the discoveries of genetic links between alpha-synuclein and Parkinson's disease risk and the identification of aggregated alpha-synuclein as the main protein constituent of Lewy pathology, alpha-synuclein has emerged as the major therapeutic target in Parkinson's disease and related synucleinopathies. Following the suggestion that alpha-synuclein pathology gradually spreads through the nervous system following a stereotypic pattern and the discovery that aggregated forms of alpha-synuclein can propagate pathology from one cell to another, and thereby probably aggravate existing deficits as well as generate additional symptoms, the idea that alpha-synuclein is a viable therapeutic target gained further support. In this review we describe current challenges and possibilities with alpha-synuclein as a therapeutic target. We briefly highlight gaps in the knowledge of the role of alpha-synuclein in disease, and propose that a deeper understanding of the pathobiology of alpha-synuclein can lead to improved therapeutic strategies. We describe several treatment approaches that are currently being tested in advanced animal experiments or already are in clinical trials. We have divided them into approaches that reduce alpha-synuclein production; inhibit alpha-synuclein aggregation inside cells; promote its degradation either inside or outside cells; and reduce its uptake by neighbouring cells following release from already affected neurons. Finally, we briefly discuss challenges related to the clinical testing of alpha-synuclein therapies, for example difficulties in monitoring target engagement and the need for relatively large trials of long duration. We conclude that alpha-synuclein remains one of the most compelling therapeutic targets for Parkinson's disease, and related synucleinopathies, and that the multitude of approaches being tested provides hope for the future.
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Affiliation(s)
- Patrik Brundin
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA.
| | - Kuldip D Dave
- The Michael J Fox Foundation, New York, NY 10017, USA
| | - Jeffrey H Kordower
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
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