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Scholz K, Pattanayak R, Ekkatine R, Pair FS, Nobles A, Stone WJ, Yacoubian TA. Rab27b Promotes Lysosomal Function and Alpha-Synuclein Clearance in Neurons. J Neurosci 2025; 45:e1579242025. [PMID: 39965930 PMCID: PMC11968537 DOI: 10.1523/jneurosci.1579-24.2025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2024] [Revised: 02/04/2025] [Accepted: 02/04/2025] [Indexed: 02/20/2025] Open
Abstract
Alpha-synuclein (αsyn) is the key pathogenic protein implicated in synucleinopathies including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). In these diseases, αsyn is thought to spread between cells where it accumulates and induces pathology; however, mechanisms that drive its propagation or aggregation are poorly understood. We have previously reported that the small GTPase Rab27b is elevated in human PD and DLB and that it can mediate the autophagic clearance and toxicity of αsyn in a paracrine αsyn cell culture model. Here, we expanded our previous work and characterized the role of Rab27b in neuronal lysosomal processing and αsyn clearance. We found that Rab27b KD in this αsyn-inducible neuronal model resulted in lysosomal dysfunction and increased αsyn levels in lysosomes. Similar lysosomal proteolytic defects and enzymatic dysfunction were observed in both primary neuronal cultures and brain lysates from male and female Rab27b knock-out (KO) mice. αSyn aggregation was exacerbated in Rab27b KO neurons upon treatment with αsyn preformed fibrils. We found no changes in lysosomal counts or lysosomal pH in either model, but we did identify changes in acidic vesicle trafficking and in lysosomal enzyme maturation and localization, which may drive lysosomal dysfunction and promote αsyn aggregation. Rab27b OE enhanced lysosomal activity and reduced insoluble αsyn accumulation. Finally we found elevated Rab27b levels in human postmortem incidental Lewy body disease subjects relative to healthy controls. These data suggest the role of Rab27b in neuronal lysosomal activity and identify it as a potential therapeutic target in synucleinopathies.
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Affiliation(s)
- Kasandra Scholz
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Rudradip Pattanayak
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Roschongporn Ekkatine
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - F Sanders Pair
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Amber Nobles
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - William J Stone
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Talene A Yacoubian
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294
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2
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Athira AP, Sreekanth S, Chandran A, Lahon A. Dual Role of Extracellular Vesicles as Orchestrators of Emerging and Reemerging Virus Infections. Cell Biochem Biophys 2025; 83:159-175. [PMID: 39225901 DOI: 10.1007/s12013-024-01495-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2024] [Indexed: 09/04/2024]
Abstract
Current decade witnessed the emergence and re-emergence of many viruses, which affected public health significantly. Viruses mainly utilize host cell machinery to promote its growth, and spread of these diseases. Numerous factors influence virus-host cell interactions, of which extracellular vesicles play an important role, where they transfer information both locally and distally by enclosing viral and host-derived proteins and RNAs as their cargo. Thus, they play a dual role in mediating virus infections by promoting virus dissemination and evoking immune responses in host organisms. Moreover, it acts as a double-edged sword during these infections. Advances in extracellular vesicles regulating emerging and reemerging virus infections, particularly in the context of SARS-CoV-2, Dengue, Ebola, Zika, Chikungunya, West Nile, and Japanese Encephalitis viruses are discussed in this review.
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Affiliation(s)
- A P Athira
- Department of Viral Vaccines, Institute of Advanced Virology, Bio 360 Life Science Park, Thiruvananthapuram, Kerala, India
| | - Smrithi Sreekanth
- Department of Viral Vaccines, Institute of Advanced Virology, Bio 360 Life Science Park, Thiruvananthapuram, Kerala, India
| | - Ananthu Chandran
- Department of Viral Vaccines, Institute of Advanced Virology, Bio 360 Life Science Park, Thiruvananthapuram, Kerala, India
| | - Anismrita Lahon
- Department of Viral Vaccines, Institute of Advanced Virology, Bio 360 Life Science Park, Thiruvananthapuram, Kerala, India.
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3
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Cogan G, Brice A. [Parkinson's disease: from genetics to targeted therapies]. C R Biol 2025; 348:21-33. [PMID: 39945455 DOI: 10.5802/crbiol.174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2024] [Revised: 01/06/2025] [Accepted: 01/15/2025] [Indexed: 03/26/2025]
Abstract
Parkinson’s disease (PD) is a multifactorial disorder involving various biological pathways. However, it is more accurate not to define PD as a unique entity, but rather as a mixture of several diseases with similar phenotypes. Attempts to classify subtypes of PD based on the clinical phenotype or biomarkers were tried. Nonetheless, for a subset of individuals, the classification based on the implied gene appears to be the most practical. Although the SNCA gene was the first identified in rare patients, pathogenic variants in GBA1 and LRRK2 are the most common genetic causes or risk factors of PD, and PRKN is the most frequent gene of autosomal recessive PD. Patients with pathogenic variants in SNCA, GBA1, LRRK2 or PRKN show various clinical, anatomopathological and biochemical aspects. Therefore, these four genes associated to PD are of particular interest for the development of targeted therapies. This fact is reinforced by the reality that current approaches are only symptomatic, and no curative treatment is available today. A number of clinical trials aiming to slow or stop disease progression are running, based on the gene involved. In this review, we will discuss the therapeutic approaches targeting SNCA, GBA1, LRRK2 and PRKN.
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4
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Scholz K, Pattanayak R, Roschonporn E, Pair FS, Nobles A, Yacoubian TA. Rab27b promotes lysosomal function and alpha-synuclein clearance in neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.20.599785. [PMID: 38979346 PMCID: PMC11230153 DOI: 10.1101/2024.06.20.599785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Alpha-synuclein (αsyn) is the key pathogenic protein implicated in synucleinopathies including Parkinson's Disease (PD) and Dementia with Lewy Bodies (DLB). In these diseases, αsyn is thought to spread between cells where it accumulates and induces pathology; however, mechanisms that drive its propagation or aggregation are poorly understood. We have previously reported that the small GTPase Rab27b is elevated in human PD and DLB and that it can mediate the autophagic clearance and toxicity of αsyn in a paracrine αsyn cell culture neuronal model. Here, we expanded our previous work and further characterized a role for Rab27b in neuronal lysosomal processing and αsyn clearance. We found that Rab27b KD in this αsyn inducible neuronal model resulted in lysosomal dysfunction and increased αsyn levels in lysosomes. Similar lysosomal proteolytic defects and enzymatic dysfunction were observed in both primary neuronal cultures and brain lysates from Rab27b knockout (KO) mice. αSyn aggregation was exacerbated in Rab27b KO neurons upon treatment with αsyn preformed fibrils. We found no changes in lysosomal counts or lysosomal pH in either model, but we did identify defects in acidic vesicle trafficking in Rab27b KO primary neurons which may drive lysosomal dysfunction and promote αsyn aggregation. Rab27b OE enhanced lysosomal activity and reduced insoluble αsyn accumulation. Finally we found elevated Rab27b levels in human postmortem incidental Lewy Body Disease (iLBD) subjects relative to healthy controls. These data suggest a role for Rab27b in neuronal lysosomal activity and identify it as a potential therapeutic target in synucleinopathies.
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5
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Coukos R, Krainc D. Key genes and convergent pathogenic mechanisms in Parkinson disease. Nat Rev Neurosci 2024; 25:393-413. [PMID: 38600347 DOI: 10.1038/s41583-024-00812-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2024] [Indexed: 04/12/2024]
Abstract
Parkinson disease (PD) is a neurodegenerative disorder marked by the preferential dysfunction and death of dopaminergic neurons in the substantia nigra. The onset and progression of PD is influenced by a diversity of genetic variants, many of which lack functional characterization. To identify the most high-yield targets for therapeutic intervention, it is important to consider the core cellular compartments and functional pathways upon which the varied forms of pathogenic dysfunction may converge. Here, we review several key PD-linked proteins and pathways, focusing on the mechanisms of their potential convergence in disease pathogenesis. These dysfunctions primarily localize to a subset of subcellular compartments, including mitochondria, lysosomes and synapses. We discuss how these pathogenic mechanisms that originate in different cellular compartments may coordinately lead to cellular dysfunction and neurodegeneration in PD.
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Affiliation(s)
- Robert Coukos
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Dimitri Krainc
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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6
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Yao H, Shen Y, Song Z, Han A, Chen X, Zhang Y, Hu B. Rab11 promotes single Mauthner cell axon regeneration in vivo through axon guidance molecule Ntng2b. Exp Neurol 2024; 374:114715. [PMID: 38325655 DOI: 10.1016/j.expneurol.2024.114715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/23/2024] [Accepted: 02/03/2024] [Indexed: 02/09/2024]
Abstract
Effective axon regeneration within the central nervous system (CNS) is pivotal for achieving functional recovery following spinal cord injury (SCI). Numerous extrinsic and intrinsic factors exert influences on the axon regeneration. While prior studies have demonstrated crucial involvement of specific members the Rab protein family in axon regeneration in the peripheral nervous system (PNS), the precise function of Rab11 in CNS axon regeneration in vivo remains elusive. Thus, our study aimed to elucidate the impact of Rab11 on the axon regeneration of Mauthner cells (M-cells) in zebrafish larvae. Our findings demonstrated that overexpression of Rab11bb via single-cell electroporation significantly promoted axon regeneration in individual M-cells. Conversely, knockdown of Rab11bb inhibited the axon regeneration of M-cells. RNA-seq analysis revealed an upregulation of ntng2b following Rab11bb overexpression. As we hypothesized, overexpression of Ntng2b markedly enhanced axon regeneration, while Ntng2b knockdown in the context of Rab11bb pro-regeneration substantially hindered axon regrowth. In conclusion, our study demonstrated that Rab11 promotes axon regeneration of single M-cell in the CNS through the Rab11/axon guidance/Ntng2b pathway.
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Affiliation(s)
- Huaitong Yao
- Hefei National Research Center for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China.
| | - Yueru Shen
- Hefei National Research Center for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China.
| | - Zheng Song
- Hefei National Research Center for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China.
| | - Along Han
- Hefei National Research Center for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China.
| | - Xinghan Chen
- Hefei National Research Center for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China.
| | - Yawen Zhang
- Hefei National Research Center for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China.
| | - Bing Hu
- Hefei National Research Center for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China; Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China.
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7
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Pirone A, Ciregia F, Lazzarini G, Miragliotta V, Ronci M, Zuccarini M, Zallocco L, Beghelli D, Mazzoni MR, Lucacchini A, Giusti L. Proteomic Profiling Reveals Specific Molecular Hallmarks of the Pig Claustrum. Mol Neurobiol 2023; 60:4336-4358. [PMID: 37095366 PMCID: PMC10293365 DOI: 10.1007/s12035-023-03347-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 04/13/2023] [Indexed: 04/26/2023]
Abstract
The present study, employing a comparative proteomic approach, analyzes the protein profile of pig claustrum (CLA), putamen (PU), and insula (IN). Pig brain is an interesting model whose key translational features are its similarities with cortical and subcortical structures of human brain. A greater difference in protein spot expression was observed in CLA vs PU as compared to CLA vs IN. The deregulated proteins identified in CLA resulted to be deeply implicated in neurodegenerative (i.e., sirtuin 2, protein disulfide-isomerase 3, transketolase) and psychiatric (i.e., copine 3 and myelin basic protein) disorders in humans. Metascape analysis of differentially expressed proteins in CLA vs PU comparison suggested activation of the α-synuclein pathway and L1 recycling pathway corroborating the involvement of these anatomical structures in neurodegenerative diseases. The expression of calcium/calmodulin-dependent protein kinase and dihydropyrimidinase like 2, which are linked to these pathways, was validated using western blot analysis. Moreover, the protein data set of CLA vs PU comparison was analyzed by Ingenuity Pathways Analysis to obtain a prediction of most significant canonical pathways, upstream regulators, human diseases, and biological functions. Interestingly, inhibition of presenilin 1 (PSEN1) upstream regulator and activation of endocannabinoid neuronal synapse pathway were observed. In conclusion, this is the first study presenting an extensive proteomic analysis of pig CLA in comparison with adjacent areas, IN and PUT. These results reinforce the common origin of CLA and IN and suggest an interesting involvement of CLA in endocannabinoid circuitry, neurodegenerative, and psychiatric disorders in humans.
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Affiliation(s)
- Andrea Pirone
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy.
| | - Federica Ciregia
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Giulia Lazzarini
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | | | - Maurizio Ronci
- Department of Medical, Oral and Biotechnological Sciences, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy
- Interuniversitary Consortium for Engineering and Medicine, COIIM, Campobasso, Italy
| | - Mariachiara Zuccarini
- Department of Medical, Oral and Biotechnological Sciences, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy
| | - Lorenzo Zallocco
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Daniela Beghelli
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | | | - Antonio Lucacchini
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Laura Giusti
- School of Pharmacy, University of Camerino, Camerino, Italy
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8
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Daly JL, Danson CM, Lewis PA, Zhao L, Riccardo S, Di Filippo L, Cacchiarelli D, Lee D, Cross SJ, Heesom KJ, Xiong WC, Ballabio A, Edgar JR, Cullen PJ. Multi-omic approach characterises the neuroprotective role of retromer in regulating lysosomal health. Nat Commun 2023; 14:3086. [PMID: 37248224 PMCID: PMC10227043 DOI: 10.1038/s41467-023-38719-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 05/05/2023] [Indexed: 05/31/2023] Open
Abstract
Retromer controls cellular homeostasis through regulating integral membrane protein sorting and transport and by controlling maturation of the endo-lysosomal network. Retromer dysfunction, which is linked to neurodegenerative disorders including Parkinson's and Alzheimer's diseases, manifests in complex cellular phenotypes, though the precise nature of this dysfunction, and its relation to neurodegeneration, remain unclear. Here, we perform an integrated multi-omics approach to provide precise insight into the impact of Retromer dysfunction on endo-lysosomal health and homeostasis within a human neuroglioma cell model. We quantify widespread changes to the lysosomal proteome, indicative of broad lysosomal dysfunction and inefficient autophagic lysosome reformation, coupled with a reconfigured cell surface proteome and secretome reflective of increased lysosomal exocytosis. Through this global proteomic approach and parallel transcriptomic analysis, we provide a holistic view of Retromer function in regulating lysosomal homeostasis and emphasise its role in neuroprotection.
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Affiliation(s)
- James L Daly
- School of Biochemistry, Biomedical Sciences Building, University Walk, University of Bristol, Bristol, BS8 1TD, UK.
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, Guy's Hospital, King's College London, SE1 9RT, London, UK.
| | - Chris M Danson
- School of Biochemistry, Biomedical Sciences Building, University Walk, University of Bristol, Bristol, BS8 1TD, UK
| | - Philip A Lewis
- Bristol Proteomics Facility, School of Biochemistry, Biomedical Sciences Building, University Walk, University of Bristol, BS8 1TD, Bristol, UK
| | - Lu Zhao
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Sara Riccardo
- Telethon Institute of Genetics and Medicine, Armenise/Harvard Laboratory of Integrative Genomics, Pozzuoli, Italy
- Next Generation Diagnostic srl, Pozzuoli, Italy
| | - Lucio Di Filippo
- Telethon Institute of Genetics and Medicine, Armenise/Harvard Laboratory of Integrative Genomics, Pozzuoli, Italy
- Next Generation Diagnostic srl, Pozzuoli, Italy
| | - Davide Cacchiarelli
- Telethon Institute of Genetics and Medicine, Armenise/Harvard Laboratory of Integrative Genomics, Pozzuoli, Italy
- Department of Translational Medicine, University of Naples "Federico II", Naples, Italy
- School for Advanced Studies, University of Naples "Federico II", Naples, Italy
| | - Daehoon Lee
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Stephen J Cross
- Wolfson Bioimaging Facility, Faculty of Biomedical Sciences, University of Bristol, Bristol, UK
| | - Kate J Heesom
- Bristol Proteomics Facility, School of Biochemistry, Biomedical Sciences Building, University Walk, University of Bristol, BS8 1TD, Bristol, UK
| | - Wen-Cheng Xiong
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine, Armenise/Harvard Laboratory of Integrative Genomics, Pozzuoli, Italy
- Department of Translational Medicine, University of Naples "Federico II", Naples, Italy
- School for Advanced Studies, University of Naples "Federico II", Naples, Italy
- Department of Molecular and Human Genetics and Neurological Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - James R Edgar
- Department of Pathology, Cambridge University, Tennis Court Road, Cambridge, UK
| | - Peter J Cullen
- School of Biochemistry, Biomedical Sciences Building, University Walk, University of Bristol, Bristol, BS8 1TD, UK.
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9
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Lee RMQ, Koh TW. Genetic modifiers of synucleinopathies-lessons from experimental models. OXFORD OPEN NEUROSCIENCE 2023; 2:kvad001. [PMID: 38596238 PMCID: PMC10913850 DOI: 10.1093/oons/kvad001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/04/2023] [Accepted: 03/07/2023] [Indexed: 04/11/2024]
Abstract
α-Synuclein is a pleiotropic protein underlying a group of progressive neurodegenerative diseases, including Parkinson's disease and dementia with Lewy bodies. Together, these are known as synucleinopathies. Like all neurological diseases, understanding of disease mechanisms is hampered by the lack of access to biopsy tissues, precluding a real-time view of disease progression in the human body. This has driven researchers to devise various experimental models ranging from yeast to flies to human brain organoids, aiming to recapitulate aspects of synucleinopathies. Studies of these models have uncovered numerous genetic modifiers of α-synuclein, most of which are evolutionarily conserved. This review discusses what we have learned about disease mechanisms from these modifiers, and ways in which the study of modifiers have supported ongoing efforts to engineer disease-modifying interventions for synucleinopathies.
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Affiliation(s)
- Rachel Min Qi Lee
- Temasek Life Sciences Laboratory, 1 Research Link, Singapore, 117604, Singapore
| | - Tong-Wey Koh
- Temasek Life Sciences Laboratory, 1 Research Link, Singapore, 117604, Singapore
- Department of Biological Sciences, National University of Singapore, Block S3 #05-01, 16 Science Drive 4, Singapore, 117558, Singapore
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10
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Lin S, Leitão ADG, Fang S, Gu Y, Barber S, Gilliard-Telefoni R, Castro A, Sung K, Shen R, Florio JB, Mante ML, Ding J, Spencer B, Masliah E, Rissman RA, Wu C. Overexpression of alpha synuclein disrupts APP and Endolysosomal axonal trafficking in a mouse model of synucleinopathy. Neurobiol Dis 2023; 178:106010. [PMID: 36702318 PMCID: PMC10754494 DOI: 10.1016/j.nbd.2023.106010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
Mutations or triplication of the alpha synuclein (ASYN) gene contribute to synucleinopathies including Parkinson's disease (PD), Dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). Recent evidence suggests that ASYN also plays an important role in amyloid-induced neurotoxicity, although the mechanism(s) remains unknown. One hypothesis is that accumulation of ASYN alters endolysosomal pathways to impact axonal trafficking and processing of the amyloid precursor protein (APP). To define an axonal function for ASYN, we used a transgenic mouse model of synucleinopathy that expresses a GFP-human ASYN (GFP-hASYN) transgene and an ASYN knockout (ASYN-/-) mouse model. Our results demonstrate that expression of GFP-hASYN in primary neurons derived from a transgenic mouse impaired axonal trafficking and processing of APP. In addition, axonal transport of BACE1, Rab5, Rab7, lysosomes and mitochondria were also reduced in these neurons. Interestingly, axonal transport of these organelles was also affected in ASYN-/- neurons, suggesting that ASYN plays an important role in maintaining normal axonal transport function. Therefore, selective impairment of trafficking and processing of APP by ASYN may act as a potential mechanism to induce pathological features of Alzheimer's disease (AD) in PD patients.
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Affiliation(s)
- Suzhen Lin
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China; Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - André D G Leitão
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Savannah Fang
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Yingli Gu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Sophia Barber
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | | | - Alfredo Castro
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Kijung Sung
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Ruinan Shen
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China; Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Jazmin B Florio
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Michael L Mante
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Jianqing Ding
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Brian Spencer
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Eliezer Masliah
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Robert A Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA; VA San Diego Health System, La Jolla, CA, USA.
| | - Chengbiao Wu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA.
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11
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Wang Z, Yang D, Jiang Y, Wang Y, Niu M, Wang C, Luo H, Xu H, Li J, Zhang YW, Zhang X. Loss of RAB39B does not alter MPTP-induced Parkinson's disease-like phenotypes in mice. Front Aging Neurosci 2023; 15:1087823. [PMID: 36761179 PMCID: PMC9905435 DOI: 10.3389/fnagi.2023.1087823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/05/2023] [Indexed: 01/26/2023] Open
Abstract
Parkinson's disease (PD) is a common neurodegenerative movement disorder with undetermined etiology. A major pathological hallmark of PD is the progressive degeneration of dopaminergic neurons in the substantia nigra. Loss-of-function mutations in the RAB39B gene, which encodes a neuronal-specific small GTPase RAB39B, have been associated with X-linked intellectual disability and pathologically confirmed early-onset PD in multiple families. However, the role of RAB39B in PD pathogenesis remains elusive. In this study, we treated Rab39b knock-out (KO) mice with MPTP to explore whether RAB39B deficiency could alter MPTP-induced behavioral impairments and dopaminergic neuron degeneration. Surprisingly, we found that MPTP treatment impaired motor activity and led to loss of tyrosine hydroxylase-positive dopaminergic neurons and gliosis in both WT and Rab39b KO mice. However, RAB39B deficiency did not alter MPTP-induced impairments. These results suggest that RAB39B deficiency does not contribute to PD-like phenotypes through compromising dopaminergic neurons in mice; and its role in PD requires further scrutiny.
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Affiliation(s)
- Zijie Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Center for Brain Sciences, The First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Xiamen University, Xiamen, China,Department of Neurosurgery, Xiang’an Hospital of Xiamen University, Xiamen, China
| | - Dingting Yang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Center for Brain Sciences, The First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Xiamen University, Xiamen, China,Department of Neurosurgery, Xiang’an Hospital of Xiamen University, Xiamen, China
| | - Yiru Jiang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Center for Brain Sciences, The First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Xiamen University, Xiamen, China
| | - Yong Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Center for Brain Sciences, The First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Xiamen University, Xiamen, China
| | - Mengxi Niu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Center for Brain Sciences, The First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Xiamen University, Xiamen, China
| | - Chong Wang
- Department of Basic Medical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Hong Luo
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Center for Brain Sciences, The First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Xiamen University, Xiamen, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Center for Brain Sciences, The First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Xiamen University, Xiamen, China
| | - Jingwen Li
- Department of Neurosurgery, Xiang’an Hospital of Xiamen University, Xiamen, China
| | - Yun-wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Center for Brain Sciences, The First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Xiamen University, Xiamen, China
| | - Xian Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Center for Brain Sciences, The First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Xiamen University, Xiamen, China,*Correspondence: Xian Zhang, ✉
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12
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Estaun-Panzano J, Arotcarena ML, Bezard E. Monitoring α-synuclein aggregation. Neurobiol Dis 2023; 176:105966. [PMID: 36527982 PMCID: PMC9875312 DOI: 10.1016/j.nbd.2022.105966] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Synucleinopathies, including Parkinson's disease (PD), dementia with Lewy Bodies (DLB), and multiple system atrophy (MSA), are characterized by the misfolding and subsequent aggregation of alpha-synuclein (α-syn) that accumulates in cytoplasmic inclusions bodies in the cells of affected brain regions. Since the seminal report of likely-aggregated α-syn presence within the Lewy bodies by Spillantini et al. in 1997, the keyword "synuclein aggregation" has appeared in over 6000 papers (Source: PubMed October 2022). Studying, observing, describing, and quantifying α-syn aggregation is therefore of paramount importance, whether it happens in tubo, in vitro, in post-mortem samples, or in vivo. The past few years have witnessed tremendous progress in understanding aggregation mechanisms and identifying various polymorphs. In this context of growing complexity, it is of utmost importance to understand what tools we possess, what exact information they provide, and in what context they may be applied. Nonetheless, it is also crucial to rationalize the relevance of the information and the limitations of these methods for gauging the final result. In this review, we present the main techniques that have shaped the current views about α-syn structure and dynamics, with particular emphasis on the recent breakthroughs that may change our understanding of synucleinopathies.
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Affiliation(s)
| | | | - Erwan Bezard
- Univ. Bordeaux, CNRS, IMN, UMR 5293, F-33000 Bordeaux, France; Motac Neuroscience Ltd, Manchester, United Kingdom.
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13
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Neupane S, De Cecco E, Aguzzi A. The Hidden Cell-to-Cell Trail of α-Synuclein Aggregates. J Mol Biol 2022:167930. [PMID: 36566800 DOI: 10.1016/j.jmb.2022.167930] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/10/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
The progressive accumulation of insoluble aggregates of the presynaptic protein alpha-synuclein (α-Syn) is a hallmark of neurodegenerative disorders including Parkinson's disease (PD), Multiple System Atrophy, and Dementia with Lewy Bodies, commonly referred to as synucleinopathies. Despite considerable progress on the structural biology of these aggregates, the molecular mechanisms mediating their cell-to-cell transmission, propagation, and neurotoxicity remain only partially understood. Numerous studies have highlighted the stereotypical spatiotemporal spreading of pathological α-Syn aggregates across different tissues and anatomically connected brain regions over time. Experimental evidence from various cellular and animal models indicate that α-Syn transfer occurs in two defined steps: the release of pathogenic α-Syn species from infected cells, and their uptake via passive or active endocytic pathways. Once α-Syn aggregates have been internalized, little is known about what drives their toxicity or how they interact with the endogenous protein to promote its misfolding and subsequent aggregation. Similarly, unknown genetic factors modulate different cellular responses to the aggregation and accumulation of pathogenic α-Syn species. Here we discuss the current understanding of the molecular phenomena associated with the intercellular spreading of pathogenic α-Syn seeds and summarize the evidence supporting the transmission hypothesis. Understanding the molecular mechanisms involved in α-Syn aggregates transmission is essential to develop novel targeted therapeutics against PD and related synucleinopathies.
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Affiliation(s)
- Sandesh Neupane
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Schmelzbergstrasse 12, 8091 Zurich, Switzerland. https://twitter.com/neuron_sandesh
| | - Elena De Cecco
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Schmelzbergstrasse 12, 8091 Zurich, Switzerland.
| | - Adriano Aguzzi
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Schmelzbergstrasse 12, 8091 Zurich, Switzerland.
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14
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Abstract
Vesicles mediate the trafficking of membranes/proteins in the endocytic and secretory pathways. These pathways are regulated by small GTPases of the Rab family. Rab proteins belong to the Ras superfamily of GTPases, which are significantly involved in various intracellular trafficking and signaling processes in the nervous system. Rab11 is known to play a key role especially in recycling many proteins, including receptors important for signal transduction and preservation of functional activities of nerve cells. Rab11 activity is controlled by GEFs (guanine exchange factors) and GAPs (GTPase activating proteins), which regulate its function through modulating GTP/GDP exchange and the intrinsic GTPase activity, respectively. Rab11 is involved in the transport of several growth factor molecules important for the development and repair of neurons. Overexpression of Rab11 has been shown to significantly enhance vesicle trafficking. On the other hand, a reduced expression of Rab11 was observed in several neurodegenerative diseases. Current evidence appears to support the notion that Rab11 and its cognate proteins may be potential targets for therapeutic intervention. In this review, we briefly discuss the function of Rab11 and its related interaction partners in intracellular pathways that may be involved in neurodegenerative processes.
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Affiliation(s)
| | - Jiri Novotny
- Jiri Novotny, Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic.
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15
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López-Cerdán A, Andreu Z, Hidalgo MR, Grillo-Risco R, Català-Senent JF, Soler-Sáez I, Neva-Alejo A, Gordillo F, de la Iglesia-Vayá M, García-García F. Unveiling sex-based differences in Parkinson's disease: a comprehensive meta-analysis of transcriptomic studies. Biol Sex Differ 2022; 13:68. [PMID: 36414996 PMCID: PMC9682715 DOI: 10.1186/s13293-022-00477-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 11/01/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND In recent decades, increasing longevity (among other factors) has fostered a rise in Parkinson's disease incidence. Although not exhaustively studied in this devastating disease, the impact of sex represents a critical variable in Parkinson's disease as epidemiological and clinical features differ between males and females. METHODS To study sex bias in Parkinson's disease, we conducted a systematic review to select sex-labeled transcriptomic data from three relevant brain tissues: the frontal cortex, the striatum, and the substantia nigra. We performed differential expression analysis on each study chosen. Then we summarized the individual differential expression results with three tissue-specific meta-analyses and a global all-tissues meta-analysis. Finally, results from the meta-analysis were functionally characterized using different functional profiling approaches. RESULTS The tissue-specific meta-analyses linked Parkinson's disease to the enhanced expression of MED31 in the female frontal cortex and the dysregulation of 237 genes in the substantia nigra. The global meta-analysis detected 15 genes with sex-differential patterns in Parkinson's disease, which participate in mitochondrial function, oxidative stress, neuronal degeneration, and cell death. Furthermore, functional analyses identified pathways, protein-protein interaction networks, and transcription factors that differed by sex. While male patients exhibited changes in oxidative stress based on metal ions, inflammation, and angiogenesis, female patients exhibited dysfunctions in mitochondrial and lysosomal activity, antigen processing and presentation functions, and glutamic and purine metabolism. All results generated during this study are readily available by accessing an open web resource ( http://bioinfo.cipf.es/metafun-pd/ ) for consultation and reuse in further studies. CONCLUSIONS Our in silico approach has highlighted sex-based differential mechanisms in typical Parkinson Disease hallmarks (inflammation, mitochondrial dysfunction, and oxidative stress). Additionally, we have identified specific genes and transcription factors for male and female Parkinson Disease patients that represent potential candidates as biomarkers to diagnosis.
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Affiliation(s)
- Adolfo López-Cerdán
- Bioinformatics and Biostatistics Unit, Principe Felipe Research Center (CIPF), 46012, Valencia, Spain
- Biomedical Imaging Unit FISABIO-CIPF, Fundación Para El Fomento de La Investigación Sanitaria Y Biomédica de La Comunidad Valenciana, 46012, Valencia, Spain
| | - Zoraida Andreu
- Foundation Valencian Institute of Oncology (FIVO), 46009, Valencia, Spain
| | - Marta R Hidalgo
- Bioinformatics and Biostatistics Unit, Principe Felipe Research Center (CIPF), 46012, Valencia, Spain
| | - Rubén Grillo-Risco
- Bioinformatics and Biostatistics Unit, Principe Felipe Research Center (CIPF), 46012, Valencia, Spain
| | | | - Irene Soler-Sáez
- Bioinformatics and Biostatistics Unit, Principe Felipe Research Center (CIPF), 46012, Valencia, Spain
| | - Almudena Neva-Alejo
- Bioinformatics and Biostatistics Unit, Principe Felipe Research Center (CIPF), 46012, Valencia, Spain
| | - Fernando Gordillo
- Bioinformatics and Biostatistics Unit, Principe Felipe Research Center (CIPF), 46012, Valencia, Spain
| | - María de la Iglesia-Vayá
- Biomedical Imaging Unit FISABIO-CIPF, Fundación Para El Fomento de La Investigación Sanitaria Y Biomédica de La Comunidad Valenciana, 46012, Valencia, Spain
| | - Francisco García-García
- Bioinformatics and Biostatistics Unit, Principe Felipe Research Center (CIPF), 46012, Valencia, Spain.
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16
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Ho PWL, Chang EES, Leung CT, Liu H, Malki Y, Pang SYY, Choi ZYK, Liang Y, Lai WS, Ruan Y, Leung KMY, Yung S, Mak JCW, Kung MHW, Ramsden DB, Ho SL. Long-term inhibition of mutant LRRK2 hyper-kinase activity reduced mouse brain α-synuclein oligomers without adverse effects. NPJ Parkinsons Dis 2022; 8:115. [PMID: 36088364 PMCID: PMC9464237 DOI: 10.1038/s41531-022-00386-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 08/30/2022] [Indexed: 11/30/2022] Open
Abstract
Parkinson’s disease (PD) is characterized by dopaminergic neurodegeneration in nigrostriatal and cortical brain regions associated with pathogenic α-synuclein (αSyn) aggregate/oligomer accumulation. LRRK2 hyperactivity is a disease-modifying therapeutic target in PD. However, LRRK2 inhibition may be associated with peripheral effects, albeit with unclear clinical consequences. Here, we significantly reduced αSyn oligomer accumulation in mouse striatum through long-term LRRK2 inhibition using GNE-7915 (specific brain-penetrant LRRK2 inhibitor) without causing adverse peripheral effects. GNE-7915 concentrations in wild-type (WT) mouse sera and brain samples reached a peak at 1 h, which gradually decreased over 24 h following a single subcutaneous (100 mg/kg) injection. The same dose in young WT and LRRK2R1441G mutant mice significantly inhibited LRRK2 kinase activity (Thr73-Rab10 and Ser106-Rab12 phosphorylation) in the lung, which dissipated by 72 h post-injection. 14-month-old mutant mice injected with GNE-7915 twice weekly for 18 weeks (equivalent to ~13 human years) exhibited reduced striatal αSyn oligomer and cortical pSer129-αSyn levels, correlating with inhibition of LRRK2 hyperactivity in brain and lung to WT levels. No GNE-7915-treated mice showed increased mortality or morbidity. Unlike reports of abnormalities in lung and kidney at acute high doses of LRRK2 inhibitors, our GNE-7915-treated mice did not exhibit swollen lamellar bodies in type II pneumocytes or abnormal vacuolation in the kidney. Functional and histopathological assessments of lung, kidney and liver, including whole-body plethysmography, urinary albumin-creatinine ratio (ACR), serum alanine aminotransferase (ALT) and serum interleukin-6 (inflammatory marker) did not reveal abnormalities after long-term GNE-7915 treatment. Long-term inhibition of mutant LRRK2 hyper-kinase activity to physiological levels presents an efficacious and safe disease-modifying therapy to ameliorate synucleinopathy in PD.
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17
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Santos-Durán GN, Barreiro-Iglesias A. Roles of dual specificity tyrosine-phosphorylation-regulated kinase 2 in nervous system development and disease. Front Neurosci 2022; 16:994256. [PMID: 36161154 PMCID: PMC9492948 DOI: 10.3389/fnins.2022.994256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 08/18/2022] [Indexed: 11/18/2022] Open
Abstract
Dual specificity tyrosine-phosphorylation-regulated kinases (DYRKs) are a group of conserved eukaryotic kinases phosphorylating tyrosine, serine, and threonine residues. The human DYRK family comprises 5 members (DYRK1A, DYRK1B, DYRK2, DYRK3, and DYRK4). The different DYRKs have been implicated in neurological diseases, cancer, and virus infection. Specifically, DYRK2 has been mainly implicated in cancer progression. However, its role in healthy and pathological nervous system function has been overlooked. In this context, we review current available data on DYRK2 in the nervous system, where the available studies indicate that it has key roles in neuronal development and function. DYRK2 regulates neuronal morphogenesis (e.g., axon growth and branching) by phosphorylating cytoskeletal elements (e.g., doublecortin). Comparative data reveals that it is involved in the development of olfactory and visual systems, the spinal cord and possibly the cortex. DYRK2 also participates in processes such as olfaction, vision and, learning. However, DYRK2 could be involved in other brain functions since available expression data shows that it is expressed across the whole brain. High DYRK2 protein levels have been detected in basal ganglia and cerebellum. In adult nervous system, DYRK2 mRNA expression is highest in the cortex, hippocampus, and retina. Regarding nervous system disease, DYRK2 has been implicated in neuroblastoma, glioma, epilepsy, neuroinflammation, Alzheimer's disease, Parkinson's disease, spinal cord injury and virus infection. DYRK2 upregulation usually has a negative impact in cancer-related conditions and a positive impact in non-malignant conditions. Its role in axon growth makes DYRK2 as a promising target for spinal cord or brain injury and regeneration.
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Affiliation(s)
| | - Antón Barreiro-Iglesias
- Department of Functional Biology, Faculty of Biology, CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
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18
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Bellucci A, Longhena F, Spillantini MG. The Role of Rab Proteins in Parkinson's Disease Synaptopathy. Biomedicines 2022; 10:biomedicines10081941. [PMID: 36009486 PMCID: PMC9406004 DOI: 10.3390/biomedicines10081941] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/31/2022] [Accepted: 08/08/2022] [Indexed: 12/29/2022] Open
Abstract
In patients affected by Parkinson's disease (PD), the most common neurodegenerative movement disorder, the brain is characterized by the loss of dopaminergic neurons in the nigrostriatal system, leading to dyshomeostasis of the basal ganglia network activity that is linked to motility dysfunction. PD mostly arises as an age-associated sporadic disease, but several genetic forms also exist. Compelling evidence supports that synaptic damage and dysfunction characterize the very early phases of either sporadic or genetic forms of PD and that this early PD synaptopathy drives retrograde terminal-to-cell body degeneration, culminating in neuronal loss. The Ras-associated binding protein (Rab) family of small GTPases, which is involved in the maintenance of neuronal vesicular trafficking, synaptic architecture and function in the central nervous system, has recently emerged among the major players in PD synaptopathy. In this manuscript, we provide an overview of the main findings supporting the involvement of Rabs in either sporadic or genetic PD pathophysiology, and we highlight how Rab alterations participate in the onset of early synaptic damage and dysfunction.
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Affiliation(s)
- Arianna Bellucci
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
- Correspondence: ; Tel.: +39-0303-717-380
| | - Francesca Longhena
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
- Department of Clinical Neurosciences, University of Cambridge, Clifford Albutt Building, Cambridge CB2 0AH, UK
| | - Maria Grazia Spillantini
- Department of Clinical Neurosciences, University of Cambridge, Clifford Albutt Building, Cambridge CB2 0AH, UK
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19
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Hallacli E, Kayatekin C, Nazeen S, Wang XH, Sheinkopf Z, Sathyakumar S, Sarkar S, Jiang X, Dong X, Di Maio R, Wang W, Keeney MT, Felsky D, Sandoe J, Vahdatshoar A, Udeshi ND, Mani DR, Carr SA, Lindquist S, De Jager PL, Bartel DP, Myers CL, Greenamyre JT, Feany MB, Sunyaev SR, Chung CY, Khurana V. The Parkinson's disease protein alpha-synuclein is a modulator of processing bodies and mRNA stability. Cell 2022; 185:2035-2056.e33. [PMID: 35688132 DOI: 10.1016/j.cell.2022.05.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 04/05/2022] [Accepted: 05/06/2022] [Indexed: 12/13/2022]
Abstract
Alpha-synuclein (αS) is a conformationally plastic protein that reversibly binds to cellular membranes. It aggregates and is genetically linked to Parkinson's disease (PD). Here, we show that αS directly modulates processing bodies (P-bodies), membraneless organelles that function in mRNA turnover and storage. The N terminus of αS, but not other synucleins, dictates mutually exclusive binding either to cellular membranes or to P-bodies in the cytosol. αS associates with multiple decapping proteins in close proximity on the Edc4 scaffold. As αS pathologically accumulates, aberrant interaction with Edc4 occurs at the expense of physiologic decapping-module interactions. mRNA decay kinetics within PD-relevant pathways are correspondingly disrupted in PD patient neurons and brain. Genetic modulation of P-body components alters αS toxicity, and human genetic analysis lends support to the disease-relevance of these interactions. Beyond revealing an unexpected aspect of αS function and pathology, our data highlight the versatility of conformationally plastic proteins with high intrinsic disorder.
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Affiliation(s)
- Erinc Hallacli
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Division of Movement Disorders, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Can Kayatekin
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Sumaiya Nazeen
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Division of Movement Disorders, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115
| | - Xiou H Wang
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Division of Movement Disorders, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Zoe Sheinkopf
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Division of Movement Disorders, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Shubhangi Sathyakumar
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Division of Movement Disorders, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Souvarish Sarkar
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Xin Jiang
- Yumanity Therapeutics, Boston, MA 02135, USA
| | - Xianjun Dong
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Genomics and Bioinformatics Hub, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Roberto Di Maio
- Pittsburgh Institute for Neurodegenerative Diseases and Department of Neurology, Pittsburgh, PA 15213, USA
| | - Wen Wang
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Matthew T Keeney
- Pittsburgh Institute for Neurodegenerative Diseases and Department of Neurology, Pittsburgh, PA 15213, USA
| | - Daniel Felsky
- Krembil Centre for Neuroinformatics and Department of Psychiatry, University of Toronto, Toronto, ON M5T 1R8, Canada; Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada; Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, 155 College Street, Toronto, ON M5T 3M7, Canada
| | - Jackson Sandoe
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Aazam Vahdatshoar
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Division of Movement Disorders, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | | | - D R Mani
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Steven A Carr
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Susan Lindquist
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02142, USA; Department of Biology, MIT, Cambridge, MA 02139, USA
| | - Philip L De Jager
- Center for Translational & Computational Neuroimmunology, Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - David P Bartel
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02142, USA; Department of Biology, MIT, Cambridge, MA 02139, USA
| | - Chad L Myers
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - J Timothy Greenamyre
- Pittsburgh Institute for Neurodegenerative Diseases and Department of Neurology, Pittsburgh, PA 15213, USA
| | - Mel B Feany
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Shamil R Sunyaev
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115
| | | | - Vikram Khurana
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Division of Movement Disorders, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA.
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20
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Jordan KL, Koss DJ, Outeiro TF, Giorgini F. Therapeutic Targeting of Rab GTPases: Relevance for Alzheimer's Disease. Biomedicines 2022; 10:1141. [PMID: 35625878 PMCID: PMC9138223 DOI: 10.3390/biomedicines10051141] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/22/2022] [Accepted: 04/18/2022] [Indexed: 11/16/2022] Open
Abstract
Rab GTPases (Rabs) are small proteins that play crucial roles in vesicle transport and membrane trafficking. Owing to their widespread functions in several steps of vesicle trafficking, Rabs have been implicated in the pathogenesis of several disorders, including cancer, diabetes, and multiple neurodegenerative diseases. As treatments for neurodegenerative conditions are currently rather limited, the identification and validation of novel therapeutic targets, such as Rabs, is of great importance. This review summarises proof-of-concept studies, demonstrating that modulation of Rab GTPases in the context of Alzheimer's disease (AD) can ameliorate disease-related phenotypes, and provides an overview of the current state of the art for the pharmacological targeting of Rabs. Finally, we also discuss the barriers and challenges of therapeutically targeting these small proteins in humans, especially in the context of AD.
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Affiliation(s)
- Kate L. Jordan
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester LE1 7RH, UK;
| | - David J. Koss
- Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; (D.J.K.); (T.F.O.)
| | - Tiago F. Outeiro
- Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; (D.J.K.); (T.F.O.)
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany
- Max Planck Institute for Natural Sciences, 37075 Göttingen, Germany
- Scientific Employee with a Honorary Contract at Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 37075 Göttingen, Germany
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester LE1 7RH, UK;
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21
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Chang EES, Ho PWL, Liu HF, Pang SYY, Leung CT, Malki Y, Choi ZYK, Ramsden DB, Ho SL. LRRK2 mutant knock-in mouse models: therapeutic relevance in Parkinson's disease. Transl Neurodegener 2022; 11:10. [PMID: 35152914 PMCID: PMC8842874 DOI: 10.1186/s40035-022-00285-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 01/26/2022] [Indexed: 12/24/2022] Open
Abstract
Mutations in the leucine-rich repeat kinase 2 gene (LRRK2) are one of the most frequent genetic causes of both familial and sporadic Parkinson's disease (PD). Mounting evidence has demonstrated pathological similarities between LRRK2-associated PD (LRRK2-PD) and sporadic PD, suggesting that LRRK2 is a potential disease modulator and a therapeutic target in PD. LRRK2 mutant knock-in (KI) mouse models display subtle alterations in pathological aspects that mirror early-stage PD, including increased susceptibility of nigrostriatal neurotransmission, development of motor and non-motor symptoms, mitochondrial and autophagy-lysosomal defects and synucleinopathies. This review provides a rationale for the use of LRRK2 KI mice to investigate the LRRK2-mediated pathogenesis of PD and implications from current findings from different LRRK2 KI mouse models, and ultimately discusses the therapeutic potentials against LRRK2-associated pathologies in PD.
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Affiliation(s)
- Eunice Eun Seo Chang
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Philip Wing-Lok Ho
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Pok Fu Lam, Hong Kong, China.
| | - Hui-Fang Liu
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Shirley Yin-Yu Pang
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Chi-Ting Leung
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Yasine Malki
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Zoe Yuen-Kiu Choi
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - David Boyer Ramsden
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Shu-Leong Ho
- Division of Neurology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Pok Fu Lam, Hong Kong, China.
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22
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Abstract
The neuronal ceroid lipofuscinoses (NCLs), collectively known as Batten disease, are a group of neurological diseases that affect all ages and ethnicities worldwide. There are 13 different subtypes of NCL, each caused by a mutation in a distinct gene. The NCLs are characterized by the accumulation of undigestible lipids and proteins in various cell types. This leads to progressive neurodegeneration and clinical symptoms including vision loss, progressive motor and cognitive decline, seizures, and premature death. These diseases have commonly been characterized by lysosomal defects leading to the accumulation of undigestible material but further research on the NCLs suggests that altered protein secretion may also play an important role. This has been strengthened by recent work in biomedical model organisms, including Dictyostelium discoideum, mice, and sheep. Research in D. discoideum has reported the extracellular localization of some NCL-related proteins and the effects of NCL-related gene loss on protein secretion during unicellular growth and multicellular development. Aberrant protein secretion has also been observed in mammalian models of NCL, which has allowed examination of patient-derived cerebrospinal fluid and urine for potential diagnostic and prognostic biomarkers. Accumulated evidence links seven of the 13 known NCL-related genes to protein secretion, suggesting that altered secretion is a common hallmark of multiple NCL subtypes. This Review highlights the impact of altered protein secretion in the NCLs, identifies potential biomarkers of interest and suggests that future work in this area can provide new therapeutic insight. Summary: This Review discusses work in different model systems and humans, examining the impact of altered protein secretion in the neuronal ceroid lipofuscinoses group of diseases to provide novel therapeutic insights.
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Affiliation(s)
- Robert J Huber
- Department of Biology, Trent University, Life & Health Sciences Building, 1600 West Bank Drive, Peterborough, Ontario K9L 0G2, Canada
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Focus on the Small GTPase Rab1: A Key Player in the Pathogenesis of Parkinson's Disease. Int J Mol Sci 2021; 22:ijms222112087. [PMID: 34769517 PMCID: PMC8584362 DOI: 10.3390/ijms222112087] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/04/2021] [Accepted: 11/06/2021] [Indexed: 12/19/2022] Open
Abstract
Parkinson’s disease (PD) is the second most frequent neurodegenerative disease. It is characterized by the loss of dopaminergic neurons in the substantia nigra and the formation of large aggregates in the survival neurons called Lewy bodies, which mainly contain α-synuclein (α-syn). The cause of cell death is not known but could be due to mitochondrial dysfunction, protein homeostasis failure, and alterations in the secretory/endolysosomal/autophagic pathways. Survival nigral neurons overexpress the small GTPase Rab1. This protein is considered a housekeeping Rab that is necessary to support the secretory pathway, the maintenance of the Golgi complex structure, and the regulation of macroautophagy from yeast to humans. It is also involved in signaling, carcinogenesis, and infection for some pathogens. It has been shown that it is directly linked to the pathogenesis of PD and other neurodegenerative diseases. It has a protective effect against α–σψν toxicity and has recently been shown to be a substrate of LRRK2, which is the most common cause of familial PD and the risk of sporadic disease. In this review, we analyze the key aspects of Rab1 function in dopamine neurons and its implications in PD neurodegeneration/restauration. The results of the current and former research support the notion that this GTPase is a good candidate for therapeutic strategies.
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Koss DJ, Campesan S, Giorgini F, Outeiro TF. Dysfunction of RAB39B-Mediated Vesicular Trafficking in Lewy Body Diseases. Mov Disord 2021; 36:1744-1758. [PMID: 33939203 DOI: 10.1002/mds.28605] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 12/16/2022] Open
Abstract
Intracellular vesicular trafficking is essential for neuronal development, function, and homeostasis and serves to process, direct, and sort proteins, lipids, and other cargo throughout the cell. This intricate system of membrane trafficking between different compartments is tightly orchestrated by Ras analog in brain (RAB) GTPases and their effectors. Of the 66 members of the RAB family in humans, many have been implicated in neurodegenerative diseases and impairment of their functions contributes to cellular stress, protein aggregation, and death. Critically, RAB39B loss-of-function mutations are known to be associated with X-linked intellectual disability and with rare early-onset Parkinson's disease. Moreover, recent studies have highlighted altered RAB39B expression in idiopathic cases of several Lewy body diseases (LBDs). This review contextualizes the role of RAB proteins in LBDs and highlights the consequences of RAB39B impairment in terms of endosomal trafficking, neurite outgrowth, synaptic maturation, autophagy, as well as alpha-synuclein homeostasis. Additionally, the potential for therapeutic intervention is examined via a discussion of the recent progress towards the development of specific RAB modulators. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- David J Koss
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Susanna Campesan
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, UK
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, UK
| | - Tiago F Outeiro
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany.,Max Planck Institute for Experimental Medicine, Goettingen, Germany.,Scientific employee with a honorary contract at Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Göttingen, Germany
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Milanese C, Gabriels S, Barnhoorn S, Cerri S, Ulusoy A, Gornati SV, Wallace DF, Blandini F, Di Monte DA, Subramaniam VN, Mastroberardino PG. Gender biased neuroprotective effect of Transferrin Receptor 2 deletion in multiple models of Parkinson's disease. Cell Death Differ 2021; 28:1720-1732. [PMID: 33323945 PMCID: PMC8166951 DOI: 10.1038/s41418-020-00698-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 11/16/2020] [Accepted: 11/24/2020] [Indexed: 01/28/2023] Open
Abstract
Alterations in the metabolism of iron and its accumulation in the substantia nigra pars compacta accompany the pathogenesis of Parkinson's disease (PD). Changes in iron homeostasis also occur during aging, which constitutes a PD major risk factor. As such, mitigation of iron overload via chelation strategies has been considered a plausible disease modifying approach. Iron chelation, however, is imperfect because of general undesired side effects and lack of specificity; more effective approaches would rely on targeting distinctive pathways responsible for iron overload in brain regions relevant to PD and, in particular, the substantia nigra. We have previously demonstrated that the Transferrin/Transferrin Receptor 2 (TfR2) iron import mechanism functions in nigral dopaminergic neurons, is perturbed in PD models and patients, and therefore constitutes a potential therapeutic target to halt iron accumulation. To validate this hypothesis, we generated mice with targeted deletion of TfR2 in dopaminergic neurons. In these animals, we modeled PD with multiple approaches, based either on neurotoxin exposure or alpha-synuclein proteotoxic mechanisms. We found that TfR2 deletion can provide neuroprotection against dopaminergic degeneration, and against PD- and aging-related iron overload. The effects, however, were significantly more pronounced in females rather than in males. Our data indicate that the TfR2 iron import pathway represents an amenable strategy to hamper PD progression. Data also suggest, however, that therapeutic strategies targeting TfR2 should consider a potential sexual dimorphism in neuroprotective response.
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Affiliation(s)
- Chiara Milanese
- Department of Molecular Genetics, Rotterdam, the Netherlands ,grid.7678.e0000 0004 1757 7797IFOM-The FIRC Institute of Molecular Oncology, Milan, Italy
| | - Sylvia Gabriels
- Department of Molecular Genetics, Rotterdam, the Netherlands
| | | | | | - Ayse Ulusoy
- grid.424247.30000 0004 0438 0426German Centre for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany
| | - S. V. Gornati
- grid.5645.2000000040459992XDepartment of Neuroscience Erasmus MC, Rotterdam, the Netherlands
| | - Daniel F. Wallace
- grid.1024.70000000089150953School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD Australia
| | - Fabio Blandini
- IRCCS Mondino Foundation, 27100 Pavia, Italy ,grid.8982.b0000 0004 1762 5736Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Donato A. Di Monte
- grid.424247.30000 0004 0438 0426German Centre for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany
| | - V. Nathan Subramaniam
- grid.1024.70000000089150953School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD Australia
| | - Pier G. Mastroberardino
- Department of Molecular Genetics, Rotterdam, the Netherlands ,grid.7678.e0000 0004 1757 7797IFOM-The FIRC Institute of Molecular Oncology, Milan, Italy ,grid.158820.60000 0004 1757 2611Department of Life, Health, and Environmental Sciences, University of L’Aquila, L’Aquila, Italy
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26
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Outeiro TF. Alpha-synuclein oligomerization and aggregation: A model will always be a model: This is a response to "Monitoring alpha-synuclein oligomerization and aggregation using bimolecular fluorescence complementation assays: What you see is not always what you get". Read the reply on "Alpha-Synuclein oligomerization and aggregation: All models are useful but only if we know what they model". The articles are accompanied by a Preface "How good are cellular models?". J Neurochem 2021; 157:889-890. [PMID: 33300125 DOI: 10.1111/jnc.15264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/01/2020] [Indexed: 11/28/2022]
Affiliation(s)
- Tiago Fleming Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.,Max Planck Institute for Experimental Medicine, Göttingen, Germany.,Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, UK
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27
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Sarkar S, Olsen AL, Sygnecka K, Lohr KM, Feany MB. α-synuclein impairs autophagosome maturation through abnormal actin stabilization. PLoS Genet 2021; 17:e1009359. [PMID: 33556113 PMCID: PMC7895402 DOI: 10.1371/journal.pgen.1009359] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/19/2021] [Accepted: 01/14/2021] [Indexed: 12/15/2022] Open
Abstract
Vesicular trafficking defects, particularly those in the autophagolysosomal system, have been strongly implicated in the pathogenesis of Parkinson’s disease and related α-synucleinopathies. However, mechanisms mediating dysfunction of membrane trafficking remain incompletely understood. Using a Drosophila model of α-synuclein neurotoxicity with widespread and robust pathology, we find that human α-synuclein expression impairs autophagic flux in aging adult neurons. Genetic destabilization of the actin cytoskeleton rescues F-actin accumulation, promotes autophagosome clearance, normalizes the autophagolysosomal system, and rescues neurotoxicity in α-synuclein transgenic animals through an Arp2/3 dependent mechanism. Similarly, mitophagosomes accumulate in human α-synuclein-expressing neurons, and reversal of excessive actin stabilization promotes both clearance of these abnormal mitochondria-containing organelles and rescue of mitochondrial dysfunction. These results suggest that Arp2/3 dependent actin cytoskeleton stabilization mediates autophagic and mitophagic dysfunction and implicate failure of autophagosome maturation as a pathological mechanism in Parkinson’s disease and related α-synucleinopathies. Vesicle trafficking is a central cell biological pathway perturbed in Parkinson’s disease. Here we use a genetic approach to define an underlying mechanism by demonstrating that the key Parkinson’s disease protein α-synuclein impairs maturation of autophagosomes and mitophagosomes through Arp2/3 dependent excess stabilization of cellular actin networks.
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Affiliation(s)
- Souvarish Sarkar
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Abby L. Olsen
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Katja Sygnecka
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Kelly M. Lohr
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Mel B. Feany
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
- * E-mail:
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Fakhree MAA, Konings IBM, Kole J, Cambi A, Blum C, Claessens MMAE. The Localization of Alpha-synuclein in the Endocytic Pathway. Neuroscience 2021; 457:186-195. [PMID: 33482328 DOI: 10.1016/j.neuroscience.2021.01.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/11/2021] [Accepted: 01/11/2021] [Indexed: 01/24/2023]
Abstract
Alpha-synuclein (αS) is an intrinsically disordered protein (IDP) that is abundantly present in the brain and is associated with Parkinson's disease (PD). In spite of its abundance and its contribution to PD pathogenesis, the exact cellular function of αS remains largely unknown. The ability of αS to remodel phospholipid model membranes combined with biochemical and cellular studies suggests that αS is involved in endocytosis. To unravel with which route(s) and stage(s) of the endocytic pathway αS is associated, we quantified the colocalization between αS and endocytic marker proteins in differentiated SH-SY5Y neuronal cells, using an object based colocalization analysis. Comparison with randomized data allowed us to discriminate between structural and coincidental colocalizations. A large fraction of the αS positive vesicles colocalizes with caveolin positive vesicles, a smaller fraction colocalizes with EEA1 and Rab7. We find no structural colocalization between αS and clathrin and Rab11 positive vesicles. We conclude that in a physiological context, αS is structurally associated with caveolin dependent membrane vesiculation and is found further along the endocytic pathway, in decreasing amounts, on early and late endosomes. Our results not only shed new light on the function of αS, they also provide a possible link between αS function and vesicle trafficking malfunction in PD.
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Affiliation(s)
- Mohammad A A Fakhree
- Nanobiophysics, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Irene B M Konings
- Nanobiophysics, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jeroen Kole
- Nanobiophysics, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Alessandra Cambi
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, 6525 GA Nijmegen, The Netherlands
| | - Christian Blum
- Nanobiophysics, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Mireille M A E Claessens
- Nanobiophysics, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
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29
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Frey B, AlOkda A, Jackson MP, Riguet N, Duce JA, Lashuel HA. Monitoring alpha-synuclein oligomerization and aggregation using bimolecular fluorescence complementation assays: What you see is not always what you get. J Neurochem 2020; 157:872-888. [PMID: 32772367 PMCID: PMC8246987 DOI: 10.1111/jnc.15147] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/22/2022]
Abstract
Bimolecular fluorescence complementation (BiFC) was introduced a decade ago as a method to monitor alpha‐synuclein (α‐syn) oligomerization in intact cells. Since then, several α‐syn BiFC cellular assays and animal models have been developed based on the assumption that an increase in the fluorescent signal correlates with increased α‐syn oligomerization or aggregation. Despite the increasing use of these assays and models in mechanistic studies, target validation and drug screening, there have been no reports that (1) validate the extent to which the BiFC fluorescent signal correlates with α‐syn oligomerization at the biochemical level; (2) provide a structural characterization of the oligomers and aggregates formed by the BiFC. To address this knowledge gap, we first analysed the expression level and oligomerization properties of the individual constituents of α‐syn‐Venus, one of the most commonly used BiFC systems, in HEK‐293 & SH‐SY5Y cells from three different laboratories using multiple biochemical approaches and techniques. Next, we investigated the biochemical and aggregation properties of α‐syn upon co‐expression of both BiFC fragments. Our results show that (1) the C‐terminal‐Venus fused to α‐syn (α‐syn‐Vc) is present in much lower abundance than its counterpart with N‐terminal‐Venus fused to α‐syn (Vn‐α‐syn); (2) Vn‐α‐syn exhibits a high propensity to form oligomers and higher‐order aggregates; and (3) the expression of either or both fragments does not result in the formation of α‐syn fibrils or cellular inclusions. Furthermore, our results suggest that only a small fraction of Vn‐α‐syn is involved in the formation of the fluorescent BiFC complex and that some of the fluorescent signal may arise from the association or entrapment of α‐syn‐Vc in Vn‐α‐syn aggregates. The fact that the N‐terminal fragment exists predominantly in an aggregated state also indicates that one must exercise caution when using this system to investigate α‐syn oligomerization in cells or in vivo. Altogether, our results suggest that cellular and animal models of oligomerization, aggregation and cell‐to‐cell transmission based on the α‐syn BiFC systems should be thoroughly characterized at the biochemical level to ensure that they reproduce the process of interest and measure what they are intended to measure. ![]()
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Affiliation(s)
- Bryan Frey
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Abdelrahman AlOkda
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Matthew P Jackson
- The ALBORADA Drug Discovery Institute, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Nathan Riguet
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - James A Duce
- The ALBORADA Drug Discovery Institute, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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30
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Koss DJ, Bondarevaite O, Adams S, Leite M, Giorgini F, Attems J, Outeiro TF. RAB39B is redistributed in dementia with Lewy bodies and is sequestered within aβ plaques and Lewy bodies. Brain Pathol 2020; 31:120-132. [PMID: 32762091 PMCID: PMC8018064 DOI: 10.1111/bpa.12890] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/22/2020] [Accepted: 07/26/2020] [Indexed: 12/19/2022] Open
Abstract
Loss of function mutations within the vesicular trafficking protein Ras analogy in brain 39B (RAB39B) are associated with rare X‐linked Parkinson’s disease (PD). Physiologically, RAB39B is localized to Golgi vesicles and recycling endosomes and is required for glutamatergic receptor maturation but also for alpha‐Synuclein (aSyn) homeostasis and the inhibition of its aggregation. Despite evidence linking RAB39B to neurodegeneration, the involvement of the protein in idiopathic neurodegenerative diseases remains undetermined. Here, analysis of the spatial distribution and expression of RAB39B was conducted in post‐mortem human brain tissue from cases of dementia with Lewy bodies (DLB, n = 10), Alzheimer’s disease (AD, n = 12) and controls (n = 12). Assessment of cortical RAB39B immunoreactivity using tissue microarrays revealed an overall reduction in the area of RAB39B positive gray matter in DLB cases when compared to controls and AD cases. Strikingly, RAB39B co‐localized with beta‐amyloid (Aβ) plaques in all cases examined and was additionally present in a subpopulation of Lewy bodies (LBs) in DLB. Biochemical measures of total RAB39B levels within the temporal cortex were unchanged between DLB, AD and controls. However, upon subcellular fractionation, a reduction of RAB39B in the cytoplasmic pool was found in DLB cases, alongside an increase of phosphorylated aSyn and Aβ in whole tissue lysates. The reduction of cytoplasmic RAB39B is consistent with an impaired reserve capacity for RAB39B‐associated functions, which in turn may facilitate LB aggregation and synaptic impairment. Collectively, our data support the involvement of RAB39B in the pathogenesis of DLB and the co‐aggregation of RAB39B with Aβ in plaques suggests that age‐associated cerebral Aβ pathology may be contributory to the loss of RAB39B. Thus RAB39B, its associated functional pathways and its entrapment in aggregates may be considered as future targets for therapeutic interventions to impede the overall pathological burden and cellular dysfunction in Lewy body diseases.
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Affiliation(s)
- David J Koss
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK
| | - Odeta Bondarevaite
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK
| | - Sara Adams
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK
| | - Marta Leite
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Johannes Attems
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK
| | - Tiago F Outeiro
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK.,Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany.,Max Planck Institute for Experimental Medicine, Goettingen, Germany
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31
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O’Sullivan MJ, Lindsay AJ. The Endosomal Recycling Pathway-At the Crossroads of the Cell. Int J Mol Sci 2020; 21:ijms21176074. [PMID: 32842549 PMCID: PMC7503921 DOI: 10.3390/ijms21176074] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 08/17/2020] [Accepted: 08/21/2020] [Indexed: 12/14/2022] Open
Abstract
The endosomal recycling pathway lies at the heart of the membrane trafficking machinery in the cell. It plays a central role in determining the composition of the plasma membrane and is thus critical for normal cellular homeostasis. However, defective endosomal recycling has been linked to a wide range of diseases, including cancer and some of the most common neurological disorders. It is also frequently subverted by many diverse human pathogens in order to successfully infect cells. Despite its importance, endosomal recycling remains relatively understudied in comparison to the endocytic and secretory transport pathways. A greater understanding of the molecular mechanisms that support transport through the endosomal recycling pathway will provide deeper insights into the pathophysiology of disease and will likely identify new approaches for their detection and treatment. This review will provide an overview of the normal physiological role of the endosomal recycling pathway, describe the consequences when it malfunctions, and discuss potential strategies for modulating its activity.
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32
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Abstract
Parkinson's disease (PD) is a leading cause of neurodegeneration that is defined by the selective loss of dopaminergic neurons and the accumulation of protein aggregates called Lewy bodies (LBs). The unequivocal identification of Mendelian inherited mutations in 13 genes in PD has provided transforming insights into the pathogenesis of this disease. The mechanistic analysis of several PD genes, including α-synuclein (α-syn), leucine-rich repeat kinase 2 (LRRK2), PTEN-induced kinase 1 (PINK1), and Parkin, has revealed central roles for protein aggregation, mitochondrial damage, and defects in endolysosomal trafficking in PD neurodegeneration. In this review, we outline recent advances in our understanding of these gene pathways with a focus on the emergent role of Rab (Ras analog in brain) GTPases and vesicular trafficking as a common mechanism that underpins how mutations in PD genes lead to neuronal loss. These advances have led to previously distinct genes such as vacuolar protein-sorting-associated protein 35 (VPS35) and LRRK2 being implicated in a common signaling pathway. A greater understanding of these common nodes of vesicular trafficking will be crucial for linking other PD genes and improving patient stratification in clinical trials underway against α-syn and LRRK2 targets.
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Affiliation(s)
- Pawan Kishor Singh
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom;
| | - Miratul M K Muqit
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom;
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Underwood R, Wang B, Carico C, Whitaker RH, Placzek WJ, Yacoubian TA. The GTPase Rab27b regulates the release, autophagic clearance, and toxicity of α-synuclein. J Biol Chem 2020; 295:8005-8016. [PMID: 32350025 DOI: 10.1074/jbc.ra120.013337] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/24/2020] [Indexed: 12/25/2022] Open
Abstract
α-Synuclein (αsyn) is the primary component of proteinaceous aggregates termed Lewy bodies that pathologically define synucleinopathies including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). αsyn is hypothesized to spread through the brain in a prion-like fashion by misfolded protein forming a template for aggregation of endogenous αsyn. The cell-to-cell release and uptake of αsyn are considered important processes for its prion-like spread. Rab27b is one of several GTPases essential to the endosomal-lysosomal pathway and is implicated in protein secretion and clearance, but its role in αsyn spread has yet to be characterized. In this study, we used a paracrine αsyn in vitro neuronal model to test the impact of Rab27b on αsyn release, clearance, and toxicity. shRNA-mediated knockdown (KD) of Rab27b increased αsyn-mediated paracrine toxicity. Rab27b reduced αsyn release primarily through nonexosomal pathways, but the αsyn released after Rab27b KD was of higher-molecular-weight species, as determined by size-exclusion chromatography. Rab27b KD increased intracellular levels of insoluble αsyn and led to an accumulation of endogenous light chain 3 (LC3)-positive puncta. Rab27b KD also decreased LC3 turnover after treatment with an autophagosome-lysosome fusion inhibitor, chloroquine, indicating that Rab27b KD induces a defect in autophagic flux. Rab27b protein levels were increased in brain lysates obtained from postmortem tissues of individuals with PD and DLB compared with healthy controls. These data indicate a role for Rab27b in the release, clearance, and toxicity of αsyn and, ultimately, in the pathogenesis of synucleinopathies.
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Affiliation(s)
- Rachel Underwood
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Bing Wang
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Christine Carico
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Robert H Whitaker
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - William J Placzek
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Talene A Yacoubian
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
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Gao Y, Wilson GR, Stephenson SEM, Oulad-Abdelghani M, Charlet-Berguerand N, Bozaoglu K, McLean CA, Thomas PQ, Finkelstein DI, Lockhart PJ. Distribution of Parkinson's disease associated RAB39B in mouse brain tissue. Mol Brain 2020; 13:52. [PMID: 32228644 PMCID: PMC7106796 DOI: 10.1186/s13041-020-00584-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/10/2020] [Indexed: 12/22/2022] Open
Abstract
Pathogenic variants in the gene encoding the small GTPase Ras analogue in Brain 39b (RAB39B) are associated with early-onset parkinsonism. In this study we investigated the expression and localization of RAB39B (RNA and protein) in mouse brain tissue to gain a better understanding of its normal physiological function(s) and role in disease. We developed novel resources, including monoclonal antibodies directed against RAB39B and mice with Rab39b knockout, and performed real-time PCR and western blot analysis on whole brain lysates. To determine the spatial localization of Rab39b RNA and protein, we performed in-situ hybridization and immunohistochemistry on fresh frozen and fixed brain tissue. Our results show that RAB39B is localized throughout the cortex, hippocampus and substantia nigra of mice throughout postnatal life. We found high levels of RAB39B within MAP2 positive cortical and hippocampal neurons, and TH positive dopaminergic neurons in the substantia nigra pars compacta. Our studies support and extend current knowledge of the localization of RAB39B. We validate RAB39B as a neuron-enriched protein and demonstrate that it is present throughout the mouse cortex and hippocampus. Further, we observe high levels in the substantia nigra pars compacta, the brain region most affected in Parkinson’s disease pathology. The distribution of Rab39b is consistent with human disease associations with parkinsonism and cognitive impairment. We also describe and validate novel resources, including monoclonal antibodies directed against RAB39B and mice with Rab39b knockout, both of which are valuable tools for future studies of the molecular function of RAB39B.
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Affiliation(s)
- Yujing Gao
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, Victoria, 3052, Australia.,Department of Paediatrics, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Gabrielle R Wilson
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, Victoria, 3052, Australia.,Department of Paediatrics, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Sarah E M Stephenson
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, Victoria, 3052, Australia.,Department of Paediatrics, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Mustapha Oulad-Abdelghani
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Strasbourg University, 67400, Illkirch, France
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Strasbourg University, 67400, Illkirch, France
| | - Kiymet Bozaoglu
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, Victoria, 3052, Australia.,Department of Paediatrics, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Catriona A McLean
- Anatomical Pathology, Alfred Hospital, Melbourne, Victoria, 3004, Australia
| | - Paul Q Thomas
- Robinson Research Institute and School of Medicine, University of Adelaide, Adelaide, SA, 5005, Australia
| | - David I Finkelstein
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Paul J Lockhart
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, Victoria, 3052, Australia. .,Department of Paediatrics, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia.
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Monzón-Sandoval J, Poggiolini I, Ilmer T, Wade-Martins R, Webber C, Parkkinen L. Human-Specific Transcriptome of Ventral and Dorsal Midbrain Dopamine Neurons. Ann Neurol 2020; 87:853-868. [PMID: 32167609 PMCID: PMC8651008 DOI: 10.1002/ana.25719] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 03/11/2020] [Accepted: 03/11/2020] [Indexed: 02/01/2023]
Abstract
Objective Neuronal loss in the substantia nigra pars compacta (SNpc) in Parkinson disease (PD) is not uniform, as dopamine neurons from the ventral tier are lost more rapidly than those of the dorsal tier. Identifying the intrinsic differences that account for this differential vulnerability may provide a key for developing new treatments for PD. Methods Here, we compared the RNA‐sequenced transcriptomes of ~100 laser captured microdissected SNpc neurons from each tier from 7 healthy controls. Results Expression levels of dopaminergic markers were similar across the tiers, whereas markers specific to the neighboring ventral tegmental area were virtually undetected. After accounting for unwanted sources of variation, we identified 106 differentially expressed genes (DEGs) between the SNpc tiers. The genes higher in the dorsal/resistant SNpc tier neurons displayed coordinated patterns of expression across the human brain, their protein products had more interactions than expected by chance, and they demonstrated evidence of functional convergence. No significant shared functionality was found for genes higher in the ventral/vulnerable SNpc tier. Surprisingly but importantly, none of the identified DEGs was among the familial PD genes or genome‐wide associated loci. Finally, we found some DEGs in opposite tier orientation between human and analogous mouse populations. Interpretation Our results highlight functional enrichments of vesicular trafficking, ion transport/homeostasis and oxidative stress genes showing higher expression in the resistant neurons of the SNpc dorsal tier. Furthermore, the comparison of gene expression variation in human and mouse SNpc populations strongly argues for the need of human‐focused omics studies. ANN NEUROL 2020;87:853–868
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Affiliation(s)
- Jimena Monzón-Sandoval
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford.,UK Dementia Research Institute, Cardiff University, Cardiff
| | - Ilaria Poggiolini
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford
| | - Tobias Ilmer
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford
| | - Richard Wade-Martins
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford.,Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Caleb Webber
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford.,UK Dementia Research Institute, Cardiff University, Cardiff.,Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Laura Parkkinen
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford.,Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford
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36
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Ebanks K, Lewis PA, Bandopadhyay R. Vesicular Dysfunction and the Pathogenesis of Parkinson's Disease: Clues From Genetic Studies. Front Neurosci 2020; 13:1381. [PMID: 31969802 PMCID: PMC6960401 DOI: 10.3389/fnins.2019.01381] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 12/05/2019] [Indexed: 12/14/2022] Open
Abstract
Parkinson's disease (PD) is a common age-related neurodegenerative disorder with disabling motor symptoms and no available disease modifying treatment. The majority of the PD cases are of unknown etiology, with both genetics and environment playing important roles. Over the past 25 years, however, genetic analysis of patients with familial history of Parkinson's and, latterly, genome wide association studies (GWAS) have provided significant advances in our understanding of the causes of the disease. These genetic insights have uncovered pathways that are affected in both genetic and sporadic forms of PD. These pathways involve oxidative stress, abnormal protein homeostasis, mitochondrial dysfunction, and lysosomal defects. In addition, newly identified PD genes and GWAS nominated genes point toward synaptic changes involving vesicles. This review will highlight the genes that contribute PD risk relating to intracellular vesicle trafficking and their functional consequences. There is still much to investigate on this newly identified and converging pathway of vesicular dynamics and PD, which will aid in better understanding and suggest novel therapeutic strategies for PD patients.
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Affiliation(s)
- Kirsten Ebanks
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Department of Clinical and Motor Neuroscience, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Patrick A. Lewis
- School of Pharmacy, University of Reading, Reading, United Kingdom
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Rina Bandopadhyay
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Department of Clinical and Motor Neuroscience, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
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Abstract
Defects in membrane trafficking are hallmarks of neurodegeneration. Rab GTPases are key regulators of membrane trafficking. Alterations of Rab GTPases, or the membrane compartments they regulate, are associated with virtually all neuronal activities in health and disease. The observation that many Rab GTPases are associated with neurodegeneration has proven a challenge in the quest for cause and effect. Neurodegeneration can be a direct consequence of a defect in membrane trafficking. Alternatively, changes in membrane trafficking may be secondary consequences or cellular responses. The secondary consequences and cellular responses, in turn, may protect, represent inconsequential correlates or function as drivers of pathology. Here, we attempt to disentangle the different roles of membrane trafficking in neurodegeneration by focusing on selected associations with Alzheimer’s disease, Parkinson’s disease, Huntington’s disease and selected neuropathies. We provide an overview of current knowledge on Rab GTPase functions in neurons and review the associations of Rab GTPases with neurodegeneration with respect to the following classifications: primary cause, secondary cause driving pathology or secondary correlate. This analysis is devised to aid the interpretation of frequently observed membrane trafficking defects in neurodegeneration and facilitate the identification of true causes of pathology.
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38
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Rab GTPases: Switching to Human Diseases. Cells 2019; 8:cells8080909. [PMID: 31426400 PMCID: PMC6721686 DOI: 10.3390/cells8080909] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/13/2019] [Accepted: 08/14/2019] [Indexed: 02/07/2023] Open
Abstract
Rab proteins compose the largest family of small GTPases and control the different steps of intracellular membrane traffic. More recently, they have been shown to also regulate cell signaling, division, survival, and migration. The regulation of these processes generally occurs through recruitment of effectors and regulatory proteins, which control the association of Rab proteins to membranes and their activation state. Alterations in Rab proteins and their effectors are associated with multiple human diseases, including neurodegeneration, cancer, and infections. This review provides an overview of how the dysregulation of Rab-mediated functions and membrane trafficking contributes to these disorders. Understanding the altered dynamics of Rabs and intracellular transport defects might thus shed new light on potential therapeutic strategies.
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Harischandra DS, Ghaisas S, Zenitsky G, Jin H, Kanthasamy A, Anantharam V, Kanthasamy AG. Manganese-Induced Neurotoxicity: New Insights Into the Triad of Protein Misfolding, Mitochondrial Impairment, and Neuroinflammation. Front Neurosci 2019; 13:654. [PMID: 31293375 PMCID: PMC6606738 DOI: 10.3389/fnins.2019.00654] [Citation(s) in RCA: 164] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/06/2019] [Indexed: 12/21/2022] Open
Abstract
Occupational or environmental exposure to manganese (Mn) can lead to the development of "Manganism," a neurological condition showing certain motor symptoms similar to Parkinson's disease (PD). Like PD, Mn toxicity is seen in the central nervous system mainly affecting nigrostriatal neuronal circuitry and subsequent behavioral and motor impairments. Since the first report of Mn-induced toxicity in 1837, various experimental and epidemiological studies have been conducted to understand this disorder. While early investigations focused on the impact of high concentrations of Mn on the mitochondria and subsequent oxidative stress, current studies have attempted to elucidate the cellular and molecular pathways involved in Mn toxicity. In fact, recent reports suggest the involvement of Mn in the misfolding of proteins such as α-synuclein and amyloid, thus providing credence to the theory that environmental exposure to toxicants can either initiate or propagate neurodegenerative processes by interfering with disease-specific proteins. Besides manganism and PD, Mn has also been implicated in other neurological diseases such as Huntington's and prion diseases. While many reviews have focused on Mn homeostasis, the aim of this review is to concisely synthesize what we know about its effect primarily on the nervous system with respect to its role in protein misfolding, mitochondrial dysfunction, and consequently, neuroinflammation and neurodegeneration. Based on the current evidence, we propose a 'Mn Mechanistic Neurotoxic Triad' comprising (1) mitochondrial dysfunction and oxidative stress, (2) protein trafficking and misfolding, and (3) neuroinflammation.
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Affiliation(s)
- Dilshan S Harischandra
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Shivani Ghaisas
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Gary Zenitsky
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Huajun Jin
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Arthi Kanthasamy
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Vellareddy Anantharam
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Anumantha G Kanthasamy
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
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40
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Dysregulation in the Brain Protein Profile of Zebrafish Lacking the Parkinson’s Disease-Related Protein DJ-1. Mol Neurobiol 2019; 56:8306-8322. [DOI: 10.1007/s12035-019-01667-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 05/31/2019] [Indexed: 02/07/2023]
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41
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LRRK2, alpha-synuclein, and tau: partners in crime or unfortunate bystanders? Biochem Soc Trans 2019; 47:827-838. [PMID: 31085616 DOI: 10.1042/bst20180466] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 12/11/2022]
Abstract
The identification of genetic forms of Parkinson's disease (PD) has tremendously expanded our understanding of the players and mechanisms involved. Mutations in the genes encoding for alpha-synuclein (aSyn), LRRK2, and tau have been associated with familial and sporadic forms of the disease. aSyn is the major component of Lewy bodies and Lewy neurites, which are pathognomonic protein inclusions in PD. Hyperphosphorylated tau protein accumulates in neurofibrillary tangles in the brains of Alzheimer's disease patients but is also seen in the brains of PD patients. LRRK2 is a complex multi-domain protein with kinase and GTPase enzymatic activity. Since aSyn and tau are phosphoproteins, we review the possible interplay between the three proteins. Understanding the interplay between LRRK2, aSyn and tau is extremely important, as this may enable the identification of novel targets and pathways for therapeutic intervention.
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42
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Bonet-Ponce L, Cookson MR. The role of Rab GTPases in the pathobiology of Parkinson' disease. Curr Opin Cell Biol 2019; 59:73-80. [PMID: 31054512 DOI: 10.1016/j.ceb.2019.03.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/14/2019] [Accepted: 03/19/2019] [Indexed: 12/23/2022]
Abstract
Rab GTPases are key regulators of vesicle-mediated transport and are proposed to play a crucial role in the pathobiology of Parkinson's disease. As membrane trafficking seems to be a relevant pathway altered in Parkinson' disease, understanding the role of Rab GTPases in the disease progression could open a window for therapeutic interventions. In this review, we focus on the recent advances on the role of Rab GTPases in the biology of two main proteins involved in Parkinson's disease: LRRK2 and α-synuclein, given that mutations in their genes (LRRK2 and SNCA) cause familial and sporadic Parkinson's disease.
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Affiliation(s)
- Luis Bonet-Ponce
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mark R Cookson
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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Patel D, Xu C, Nagarajan S, Liu Z, Hemphill WO, Shi R, Uversky VN, Caldwell GA, Caldwell KA, Witt SN. Alpha-synuclein inhibits Snx3-retromer-mediated retrograde recycling of iron transporters in S. cerevisiae and C. elegans models of Parkinson's disease. Hum Mol Genet 2019; 27:1514-1532. [PMID: 29452354 DOI: 10.1093/hmg/ddy059] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 02/12/2018] [Indexed: 01/31/2023] Open
Abstract
We probed the role of alpha-synuclein (α-syn) in modulating sorting nexin 3 (Snx3)-retromer-mediated recycling of iron transporters in Saccharomyces cerevisiae and Caenorhabditis elegans. In yeast, the membrane-bound heterodimer Fet3/Ftr1 is the high affinity iron importer. Fet3 is a membrane-bound multicopper ferroxidase, whose ferroxidase domain is orthologous to human ceruloplasmin (Cp), that oxidizes external Fe+2 to Fe+3; the Fe+3 ions then channel through the Ftr1 permease into the cell. When the concentration of external iron is low (<1 µM), Fet3/Ftr1 is maintained on the plasma membrane by retrograde endocytic-recycling; whereas, when the concentration of external iron is high (>10 µM), Fet3/Ftr1 is endocytosed and shunted to the vacuole for degradation. We discovered that α-syn expression phenocopies the high iron condition: under the low iron condition (<1 µM), α-syn inhibits Snx3-retromer-mediated recycling of Fet3/Ftr1 and instead shunts Fet3/Ftr1 into the multivesicular body pathway to the vacuole. α-Syn inhibits recycling by blocking the association of Snx3-mCherry molecules with endocytic vesicles, possibly by interfering with the binding of Snx3 to phosphatidylinositol-3-monophosphate. In C. elegans, transgenic worms expressing α-syn exhibit an age-dependent degeneration of dopaminergic neurons that is partially rescued by the iron chelator desferoxamine. This implies that α-syn-expressing dopaminergic neurons are susceptible to changes in iron neurotoxicity with age, whereby excess iron enhances α-syn-induced neurodegeneration. In vivo genetic analysis indicates that α-syn dysregulates iron homeostasis in worm dopaminergic neurons, possibly by inhibiting SNX-3-mediated recycling of a membrane-bound ortholog of Cp (F21D5.3), the iron exporter ferroportin (FPN1.1), or both.
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Affiliation(s)
- Dhaval Patel
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Chuan Xu
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Sureshbabu Nagarajan
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Zhengchang Liu
- Department of Biological Sciences, The University of New Orleans, New Orleans, LA 70148, USA
| | - Wayne O Hemphill
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Runhua Shi
- Department of Medicine, Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Vladimir N Uversky
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Guy A Caldwell
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Kim A Caldwell
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Stephan N Witt
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.,Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
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Höllerhage M, Bickle M, Höglinger GU. Unbiased Screens for Modifiers of Alpha-Synuclein Toxicity. Curr Neurol Neurosci Rep 2019; 19:8. [PMID: 30739256 DOI: 10.1007/s11910-019-0925-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW We provide an overview about unbiased screens to identify modifiers of alpha-synuclein (αSyn)-induced toxicity, present the models and the libraries that have been used for screening, and describe how hits from primary screens were selected and validated. RECENT FINDINGS Screens can be classified as either genetic or chemical compound modifier screens, but a few screens do not fit this classification. Most screens addressing αSyn-induced toxicity, including genome-wide overexpressing and deletion, were performed in yeast. More recently, newer methods such as CRISPR-Cas9 became available and were used for screening purposes. Paradoxically, given that αSyn-induced toxicity plays a role in neurological diseases, there is a shortage of human cell-based models for screening. Moreover, most screens used mutant or fluorescently tagged forms of αSyn and only very few screens investigated wild-type αSyn. Particularly, no genome-wide αSyn toxicity screen in human dopaminergic neurons has been published so far. Most unbiased screens for modifiers of αSyn toxicity were performed in yeast, and there is a lack of screens performed in human and particularly dopaminergic cells.
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Affiliation(s)
- Matthias Höllerhage
- Department of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377, Munich, Germany
- Department of Neurology, Technical University of Munich (TUM), 81675, Munich, Germany
| | - Marc Bickle
- HT-Technology Development Studio, Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
| | - Günter U Höglinger
- Department of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 81377, Munich, Germany.
- Department of Neurology, Technical University of Munich (TUM), 81675, Munich, Germany.
- Munich Cluster for Systems Neurology (SyNergy), Ludwig Maximilians University (LMU), 81377, Munich, Germany.
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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: 8.0] [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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A Druggable Genome Screen Identifies Modifiers of α-Synuclein Levels via a Tiered Cross-Species Validation Approach. J Neurosci 2018; 38:9286-9301. [PMID: 30249792 DOI: 10.1523/jneurosci.0254-18.2018] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 08/08/2018] [Accepted: 08/13/2018] [Indexed: 01/12/2023] Open
Abstract
Accumulation of α-Synuclein (α-Syn) causes Parkinson's disease (PD) as well as other synucleopathies. α-Syn is the major component of Lewy bodies and Lewy neurites, the proteinaceous aggregates that are a hallmark of sporadic PD. In familial forms of PD, mutations or copy number variations in SNCA (the α-Syn gene) result in a net increase of its protein levels. Furthermore, common risk variants tied to PD are associated with small increases of wild-type α-Syn levels. These findings are further bolstered by animal studies which show that overexpression of α-Syn is sufficient to cause PD-like features. Thus, increased α-Syn levels are intrinsically tied to PD pathogenesis and underscore the importance of identifying the factors that regulate its levels. In this study, we establish a pooled RNAi screening approach and validation pipeline to probe the druggable genome for modifiers of α-Syn levels and identify 60 promising targets. Using a cross-species, tiered validation approach, we validate six strong candidates that modulate α-Syn levels and toxicity in cell lines, Drosophila, human neurons, and mouse brain of both sexes. More broadly, this genetic strategy and validation pipeline can be applied for the identification of therapeutic targets for disorders driven by dosage-sensitive proteins.SIGNIFICANCE STATEMENT We present a research strategy for the systematic identification and validation of genes modulating the levels of α-Synuclein, a protein involved in Parkinson's disease. A cell-based screen of the druggable genome (>7,500 genes that are potential therapeutic targets) yielded many modulators of α-Synuclein that were subsequently confirmed and validated in Drosophila, human neurons, and mouse brain. This approach has broad applicability to the multitude of neurological diseases that are caused by mutations in genes whose dosage is critical for brain function.
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47
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Patel D, Witt SN. Sorting Out the Role of α-Synuclein in Retromer-Mediated Endosomal Protein Sorting. J Exp Neurosci 2018; 12:1179069518796215. [PMID: 30158827 PMCID: PMC6109851 DOI: 10.1177/1179069518796215] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 08/02/2018] [Indexed: 12/04/2022] Open
Abstract
Retromer is a phylogenetically conserved, multisubunit coat complex that controls endosomal protein trafficking and sorting. Mutations in the retromer gene VPS35 cause late-onset Parkinson disease, suggesting that trafficking defects cause neurodegeneration. Sorting nexins assist retromer to guide cell surface proteins to their assigned destinations, and our interest here is sorting nexin 3 (Snx3). Snx3 binds to membranes via a phox homolog (PX) domain that binds phosphatidylinositol 3-phosphate (PI3P), and in human cells its cargo proteins are the transferrin and Wnt receptors and the divalent metal ion transporter, whereas in yeast the best characterized cargo is the iron permease Ftr1. We recently discovered that α-synuclein inhibits Snx3-retromer recycling of Ftr1 in an unexpected way: α-synuclein, which avidly binds to negatively charged lipids, blocks the association of Snx3 to early endosomes. Here, we discuss mechanisms by which α-synuclein can disrupt Snx3-retromer–mediated recycling.
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Affiliation(s)
- Dhaval Patel
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Stephan N Witt
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA, USA.,Department of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA, USA
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Masaracchia C, Hnida M, Gerhardt E, Lopes da Fonseca T, Villar-Pique A, Branco T, Stahlberg MA, Dean C, Fernández CO, Milosevic I, Outeiro TF. Membrane binding, internalization, and sorting of alpha-synuclein in the cell. Acta Neuropathol Commun 2018; 6:79. [PMID: 30107856 PMCID: PMC6090819 DOI: 10.1186/s40478-018-0578-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 07/28/2018] [Indexed: 12/31/2022] Open
Abstract
Alpha-synuclein (aSyn) plays a crucial role in Parkinson's disease (PD) and other synucleinopathies, since it misfolds and accumulates in typical proteinaceous inclusions. While the function of aSyn is thought to be related to vesicle binding and trafficking, the precise molecular mechanisms linking aSyn with synucleinopathies are still obscure. aSyn can spread in a prion-like manner between interconnected neurons, contributing to the propagation of the pathology and to the progressive nature of synucleinopathies. Here, we investigated the interaction of aSyn with membranes and trafficking machinery pathways using cellular models of PD that are amenable to detailed molecular analyses. We found that different species of aSyn can enter cells and form high molecular weight species, and that membrane binding properties are important for the internalization of aSyn. Once internalized, aSyn accumulates in intracellular inclusions. Interestingly, we found that internalization is blocked in the presence of dynamin inhibitors (blocked membrane scission), suggesting the involvement of the endocytic pathway in the internalization of aSyn. By screening a pool of small Rab-GTPase proteins (Rabs) which regulate membrane trafficking, we found that internalized aSyn partially colocalized with Rab5A and Rab7. Initially, aSyn accumulated in Rab4A-labelled vesicles and, at later stages, it reached the autophagy-lysosomal pathway (ALP) where it gets degraded. In total, our study emphasizes the importance of membrane binding, not only as part of the normal function but also as an important step in the internalization and subsequent accumulation of aSyn. Importantly, we identified a fundamental role for Rab proteins in the modulation of aSyn processing, clearance and spreading, suggesting that targeting Rab proteins may hold important therapeutic value in PD and other synucleinopathies.
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14-3-3 Proteins Reduce Cell-to-Cell Transfer and Propagation of Pathogenic α-Synuclein. J Neurosci 2018; 38:8211-8232. [PMID: 30093536 DOI: 10.1523/jneurosci.1134-18.2018] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 07/23/2018] [Accepted: 07/25/2018] [Indexed: 02/07/2023] Open
Abstract
α-Synuclein (αsyn) is the key protein that forms neuronal aggregates in the neurodegenerative disorders Parkinson's disease (PD) and dementia with Lewy bodies. Recent evidence points to the prion-like spread of αsyn from one brain region to another. Propagation of αsyn is likely dependent on release, uptake, and misfolding. Under normal circumstances, this highly expressed brain protein functions normally without promoting pathology, yet the underlying endogenous mechanisms that prevent αsyn spread are not understood. 14-3-3 proteins are highly expressed brain proteins that have chaperone function and regulate protein trafficking. In this study, we investigated the potential role of the 14-3-3 proteins in the regulation of αsyn spread using two models of αsyn spread. In a paracrine αsyn model, 14-3-3θ promoted release of αsyn complexed with 14-3-3θ. Despite higher amounts of released αsyn, extracellular αsyn showed reduced oligomerization and seeding capability, reduced internalization, and reduced toxicity in primary mixed-gender mouse neurons. 14-3-3 inhibition reduced the amount of αsyn released, yet released αsyn was more toxic and demonstrated increased oligomerization, seeding capability, and internalization. In the preformed fibril model, 14-3-3 θ reduced αsyn aggregation and neuronal death, whereas 14-3-3 inhibition enhanced αsyn aggregation and neuronal death in primary mouse neurons. 14-3-3s blocked αsyn spread to distal chamber neurons not exposed directly to fibrils in multichamber, microfluidic devices. These findings point to 14-3-3s as a direct regulator of αsyn propagation, and suggest that dysfunction of 14-3-3 function may promote αsyn pathology in PD and related synucleinopathies.SIGNIFICANCE STATEMENT Transfer of misfolded aggregates of α-synuclein from one brain region to another is implicated in the pathogenesis of Parkinson's disease and other synucleinopathies. This process is dependent on active release, internalization, and misfolding of α-synuclein. 14-3-3 proteins are highly expressed chaperone proteins that interact with α-synuclein and regulate protein trafficking. We used two different models in which toxicity is associated with cell-to-cell transfer of α-synuclein to test whether 14-3-3s impact α-synuclein toxicity. We demonstrate that 14-3-3θ reduces α-synuclein transfer and toxicity by inhibiting oligomerization, seeding capability, and internalization of α-synuclein, whereas 14-3-3 inhibition accelerates the transfer and toxicity of α-synuclein in these models. Dysfunction of 14-3-3 function may be a critical mechanism by which α-synuclein propagation occurs in disease.
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Parkinson's disease-like burst firing activity in subthalamic nucleus induced by AAV-α-synuclein is normalized by LRRK2 modulation. Neurobiol Dis 2018; 116:13-27. [DOI: 10.1016/j.nbd.2018.04.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/10/2018] [Accepted: 04/16/2018] [Indexed: 01/13/2023] Open
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