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Chaiamarit T, Verhelle A, Chassefeyre R, Shukla N, Novak SW, Andrade LR, Manor U, Encalada SE. Mutant Prion Protein Endoggresomes are Hubs for Local Axonal Organelle-Cytoskeletal Remodeling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.19.533383. [PMID: 36993610 PMCID: PMC10055262 DOI: 10.1101/2023.03.19.533383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Dystrophic axons comprising misfolded mutant prion protein (PrP) aggregates are a characteristic pathological feature in the prionopathies. These aggregates form inside endolysosomes -called endoggresomes-, within swellings that line up the length of axons of degenerating neurons. The pathways impaired by endoggresomes that result in failed axonal and consequently neuronal health, remain undefined. Here, we dissect the local subcellular impairments that occur within individual mutant PrP endoggresome swelling sites in axons. Quantitative high-resolution light and electron microscopy revealed the selective impairment of the acetylated vs tyrosinated microtubule cytoskeleton, while micro-domain image analysis of live organelle dynamics within swelling sites revealed deficits uniquely to the MT-based active transport system that translocates mitochondria and endosomes toward the synapse. Cytoskeletal and defective transport results in the retention of mitochondria, endosomes, and molecular motors at swelling sites, enhancing mitochondria-Rab7 late endosome contacts that induce mitochondrial fission via the activity of Rab7, and render mitochondria dysfunctional. Our findings point to mutant Pr Pendoggresome swelling sites as selective hubs of cytoskeletal deficits and organelle retention that drive the remodeling of organelles along axons. We propose that the dysfunction imparted locally within these axonal micro-domains spreads throughout the axon over time, leading to axonal dysfunction in prionopathies.
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Chassefeyre R, Chaiamarit T, Verhelle A, Novak SW, Andrade LR, Leitão ADG, Manor U, Encalada SE. Endosomal sorting drives the formation of axonal prion protein endoggresomes. SCIENCE ADVANCES 2021; 7:eabg3693. [PMID: 34936461 PMCID: PMC8694590 DOI: 10.1126/sciadv.abg3693] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 11/05/2021] [Indexed: 05/15/2023]
Abstract
The pathogenic aggregation of misfolded prion protein (PrP) in axons underlies prion disease pathologies. The molecular mechanisms driving axonal misfolded PrP aggregate formation leading to neurotoxicity are unknown. We found that the small endolysosomal guanosine triphosphatase (GTPase) Arl8b recruits kinesin-1 and Vps41 (HOPS) onto endosomes carrying misfolded mutant PrP to promote their axonal entry and homotypic fusion toward aggregation inside enlarged endomembranes that we call endoggresomes. This axonal rapid endosomal sorting and transport-dependent aggregation (ARESTA) mechanism forms pathologic PrP endoggresomes that impair calcium dynamics and reduce neuronal viability. Inhibiting ARESTA diminishes endoggresome formation, rescues calcium influx, and prevents neuronal death. Our results identify ARESTA as a key pathway for the regulation of endoggresome formation and a new actionable antiaggregation target to ameliorate neuronal dysfunction in the prionopathies.
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Affiliation(s)
- Romain Chassefeyre
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
- Neurodegeneration New Medicines Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Tai Chaiamarit
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
- Neurodegeneration New Medicines Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Adriaan Verhelle
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
- Neurodegeneration New Medicines Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Sammy Weiser Novak
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Leonardo R. Andrade
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - André D. G. Leitão
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
- Neurodegeneration New Medicines Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Sandra E. Encalada
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
- Neurodegeneration New Medicines Center, The Scripps Research Institute, La Jolla, CA 92037, USA
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Gao LP, Wu YZ, Xiao K, Yang XH, Chen DD, Shi Q, Dong XP. Generation and characterization of two strains of transgene mice expressing chimeric MiniSOG-MusPrP. J Neurosci Methods 2020; 341:108764. [PMID: 32416277 DOI: 10.1016/j.jneumeth.2020.108764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 04/30/2020] [Accepted: 05/06/2020] [Indexed: 11/15/2022]
Abstract
BACKGROUND Although the presences of scrapie associated fibril in the brain tissues is a ultrastructural hallmark for prion diseases, the exact morphological structure of prion during the progression of the disease is still unclear. The host prion protein (PrP) is encoded by PrP gene (PRNP) locating on the chromosome 20 in human and the chromosome 2 in mouse. Recently, a novel correlative light and electron microscopy with Mini Singlet Oxygen Generator (miniSOG) was generated. MiniSOG, a small protein of 106 amino acids, can absorb blue light and emit green fluorescence that is detectable under the fluorescence microscope. MiniSOG can also partially catalyze the polymerization of DAB to form black stained structures in the presence of osmium tetroxide, which is able to be observed under transmission electron microscope. NEW METHODS Two kinds of miniSOG-PrP expressing recombinant plasmids were generated. Correlative photooxidation and transmission electron microscope were used to detect these plasmids. The plasmids were microinjected into fertilized FVB/NJ eggs and Tg mice expressing miniSOG-PrP fusion proteins were selected after successive bred withPRNP KO Tg mice. RESULTS Those two strains of Tg mice, TgSOG23 and Tg231SOG, developed normally and maintained healthy without detectable abnormality after one-year observation. Western blots and immunohistochemical assays with PrP- and miniSOG-specific antibodies confirmed that the chimeric miniSOG-PrP proteins were expressed in the brain tissues of Tg mice. Digital PCR assays proposed that the copy numbers of the inserted external gene in TgSOG23 and Tg231SOG were 2 and 12, respectively. COMPARISON WITH EXISTING METHOD(S) Compared with GFP tag miniSOG is significantly smaller, which makes it easy be operated experimentally and possibly has less influence on the biological function of the labeled protein. Additionally, GFP tag is an ideal marker for immunofluorescent assays, but may not be suitable for ultrastructural assays for prion morphology. CONCLUSION Those Tg mice may supply novel and useful experimental animals for further study on the potential morphological structure formation and deposits of prion in the brain tissues during prion infection.
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Affiliation(s)
- Li-Ping Gao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China
| | - Yue-Zhang Wu
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China
| | - Kang Xiao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China
| | - Xue-Hua Yang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China
| | - Dong-Dong Chen
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China
| | - Qi Shi
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; China Academy of Chinese Medical Sciences, Dongzhimeinei, South Rd 16, Beijing 100700, China.
| | - Xiao-Ping Dong
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Center for Global Public Health, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan China; China Academy of Chinese Medical Sciences, Dongzhimeinei, South Rd 16, Beijing 100700, China.
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Altered distribution, aggregation, and protease resistance of cellular prion protein following intracranial inoculation. PLoS One 2019; 14:e0219457. [PMID: 31291644 PMCID: PMC6620108 DOI: 10.1371/journal.pone.0219457] [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: 12/06/2018] [Accepted: 06/24/2019] [Indexed: 11/19/2022] Open
Abstract
Prion protein (PrPC) is a protease-sensitive and soluble cell surface glycoprotein expressed in almost all mammalian cell types. PrPSc, a protease-resistant and insoluble form of PrPC, is the causative agent of prion diseases, fatal and transmissible neurogenerative diseases of mammals. Prion infection is initiated via either ingestion or inoculation of PrPSc or when host PrPC stochastically refolds into PrPSc. In either instance, the early events that occur during prion infection remain poorly understood. We have used transgenic mice expressing mouse PrPC tagged with a unique antibody epitope to monitor the response of host PrPC to prion inoculation. Following intracranial inoculation of either prion-infected or uninfected brain homogenate, we show that host PrPC can accumulate both intra-axonally and within the myelin membrane of axons suggesting that it may play a role in axonal loss following brain injury. Moreover, in response to the inoculation host PrPC exhibits an increased insolubility and protease resistance similar to that of PrPSc, even in the absence of infectious prions. Thus, our results raise the possibility that damage to the brain may be one trigger by which PrPC stochastically refolds into pathogenic PrPSc leading to productive prion infection.
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Prion protein inhibits fast axonal transport through a mechanism involving casein kinase 2. PLoS One 2017; 12:e0188340. [PMID: 29261664 PMCID: PMC5737884 DOI: 10.1371/journal.pone.0188340] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 11/06/2017] [Indexed: 12/13/2022] Open
Abstract
Prion diseases include a number of progressive neuropathies involving conformational changes in cellular prion protein (PrPc) that may be fatal sporadic, familial or infectious. Pathological evidence indicated that neurons affected in prion diseases follow a dying-back pattern of degeneration. However, specific cellular processes affected by PrPc that explain such a pattern have not yet been identified. Results from cell biological and pharmacological experiments in isolated squid axoplasm and primary cultured neurons reveal inhibition of fast axonal transport (FAT) as a novel toxic effect elicited by PrPc. Pharmacological, biochemical and cell biological experiments further indicate this toxic effect involves casein kinase 2 (CK2) activation, providing a molecular basis for the toxic effect of PrPc on FAT. CK2 was found to phosphorylate and inhibit light chain subunits of the major motor protein conventional kinesin. Collectively, these findings suggest CK2 as a novel therapeutic target to prevent the gradual loss of neuronal connectivity that characterizes prion diseases.
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Jeffrey M, González L, Simmons MM, Hunter N, Martin S, McGovern G. Altered trafficking of abnormal prion protein in atypical scrapie: prion protein accumulation in oligodendroglial inner mesaxons. Neuropathol Appl Neurobiol 2017; 43:215-226. [PMID: 26750308 DOI: 10.1111/nan.12302] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 01/04/2016] [Accepted: 01/10/2016] [Indexed: 01/09/2023]
Abstract
AIMS Prion diseases exist in classical and atypical disease forms. Both forms are characterized by disease-associated accumulation of a host membrane sialoglycoprotein known as prion protein (PrPd ). In classical forms of prion diseases, PrPd can accumulate in the extracellular space as fibrillar amyloid, intracellularly within lysosomes, but mainly on membranes in association with unique and characteristic membrane pathology. These membrane changes are found in all species and strains of classical prion diseases and consist of spiral, branched and clathrin-coated membrane invaginations on dendrites. Atypical prion diseases have been described in ruminants and man and have distinct biological, biochemical and pathological properties when compared to classical disease. The purpose of this study was to determine whether the subcellular pattern of PrPd accumulation and membrane changes in atypical scrapie were the same as those found in classical prion diseases. METHODS Immunogold electron microscopy was used to examine brains of atypical scrapie-affected sheep and Tg338 mice. RESULTS Classical prion disease-associated membrane lesions were not found in atypical scrapie-affected sheep, however, white matter PrPd accumulation was localized mainly to the inner mesaxon and paranodal cytoplasm of oligodendroglia. Similar lesions were found in myelinated axons of atypical scrapie Tg338-infected mice. However, Tg338 mice also showed the unique grey matter membrane changes seen in classical forms of disease. CONCLUSIONS These data show that atypical scrapie infection directs a change in trafficking of abnormal PrP to axons and oligodendroglia and that the resulting pathology is an interaction between the agent strain and host genotype.
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Affiliation(s)
- M Jeffrey
- Pathology Department, Animal and Plant Health Agency, Lasswade, UK
| | - L González
- Pathology Department, Animal and Plant Health Agency, Lasswade, UK
| | - M M Simmons
- Pathology Department, Animal and Plant Health Agency, Addlestone, UK
| | - N Hunter
- The Roslin Institute, University of Edinburgh, Midlothian, UK
| | - S Martin
- Pathology Department, Animal and Plant Health Agency, Lasswade, UK
| | - G McGovern
- Pathology Department, Animal and Plant Health Agency, Lasswade, UK
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Neumann S, Chassefeyre R, Campbell GE, Encalada SE. KymoAnalyzer: a software tool for the quantitative analysis of intracellular transport in neurons. Traffic 2016; 18:71-88. [PMID: 27770501 DOI: 10.1111/tra.12456] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 10/18/2016] [Accepted: 10/18/2016] [Indexed: 12/17/2022]
Abstract
In axons, proper localization of proteins, vesicles, organelles, and other cargoes is accomplished by the highly regulated coordination of kinesins and dyneins, molecular motors that bind to cargoes and translocate them along microtubule (MT) tracks. Impairment of axonal transport is implicated in the pathogenesis of multiple neurodegenerative disorders including Alzheimer's and Huntington's diseases. To understand how MT-based cargo motility is regulated and to delineate its role in neurodegeneration, it is critical to analyze the detailed dynamics of moving cargoes inside axons. Here, we present KymoAnalyzer, a software tool that facilitates the robust analysis of axonal transport from time-lapse live-imaging sequences. KymoAnalyzer is an open-source software that automatically classifies particle trajectories and systematically calculates velocities, run lengths, pauses, and a wealth of other parameters that are characteristic of motor-based transport. We anticipate that laboratories will easily use this package to unveil previously uncovered intracellular transport details of individually-moving cargoes inside neurons.
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Affiliation(s)
- Sylvia Neumann
- Department of Molecular and Experimental Medicine, Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California
| | - Romain Chassefeyre
- Department of Molecular and Experimental Medicine, Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California
| | - George E Campbell
- Department of Molecular and Experimental Medicine, Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California
| | - Sandra E Encalada
- Department of Molecular and Experimental Medicine, Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California
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Wang H, Tian C, Fan XY, Chen LN, Lv Y, Sun J, Zhao YJ, Zhang LB, Wang J, Shi Q, Gao C, Chen C, Shao QX, Dong XP. Polo-like kinase 3 (PLK3) mediates the clearance of the accumulated PrP mutants transiently expressed in cultured cells and pathogenic PrP(Sc) in prion infected cell line via protein interaction. Int J Biochem Cell Biol 2015; 62:24-35. [PMID: 25724737 DOI: 10.1016/j.biocel.2015.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 01/20/2015] [Accepted: 02/17/2015] [Indexed: 12/11/2022]
Abstract
Polo-like kinases (PLKs) family has long been known to be critical for cell cycle and recent studies have pointed to new dimensions of PLKs function in the nervous system. Our previous study has verified that the levels of PLK3 in the brain are severely downregulated in prion-related diseases. However, the associations of PLKs with prion protein remain unclear. In the present study, we confirmed that PrP protein constitutively interacts with PLK3 as determined by both in vitro and in vivo assays. Both the kinase domain and polo-box domain of PLK3 were proved to bind PrP proteins expressed in mammalian cell lines. Overexpression of PLK3 did not affect the level of wild-type PrP, but significantly decreased the levels of the mutated PrPs in cultured cells. The kinase domain appeared to be responsible for the clearance of abnormally aggregated PrPs, but this function seemed to be independent of its kinase activity. RNA-mediated knockdown of PLK3 obviously aggravated the accumulation of cytosolic PrPs. Moreover, PLK3 overexpression in a scrapie infected cell line caused notable reduce of PrP(Sc) level in a dose-dependent manner, but had minimal effect on the expression of PrP(C) in its normal partner cell line. Our findings here confirmed the molecular interaction between PLK3 and PrP and outlined the regulatory activity of PLK3 on the degradation of abnormal PrPs, even its pathogenic isoform PrP(Sc). We, therefore, assume that the recovery of PLK3 in the early stage of prion infection may be helpful to prevent the toxic accumulation of PrP(Sc) in the brain tissues.
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Affiliation(s)
- Hui Wang
- Department of Immunology, and the Key Laboratory for Laboratory Medicine of Jiangsu Province, Jiangsu University Medical School, Zhenjiang 212013, Jiangsu, China; State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China
| | - Chan Tian
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China
| | - Xue-Yu Fan
- Department of Immunology, and the Key Laboratory for Laboratory Medicine of Jiangsu Province, Jiangsu University Medical School, Zhenjiang 212013, Jiangsu, China; State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China
| | - Li-Na Chen
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China
| | - Yan Lv
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China
| | - Jing Sun
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China
| | - Yang-Jing Zhao
- Department of Immunology, and the Key Laboratory for Laboratory Medicine of Jiangsu Province, Jiangsu University Medical School, Zhenjiang 212013, Jiangsu, China
| | - Lu-bin Zhang
- Department of Immunology, and the Key Laboratory for Laboratory Medicine of Jiangsu Province, Jiangsu University Medical School, Zhenjiang 212013, Jiangsu, China
| | - Jing Wang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China
| | - Qi Shi
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China
| | - Chen Gao
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China
| | - Cao Chen
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China
| | - Qi-Xiang Shao
- Department of Immunology, and the Key Laboratory for Laboratory Medicine of Jiangsu Province, Jiangsu University Medical School, Zhenjiang 212013, Jiangsu, China.
| | - Xiao-Ping Dong
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China; Chinese Academy of Sciences Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
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Reiniger L, Mirabile I, Lukic A, Wadsworth JDF, Linehan JM, Groves M, Lowe J, Druyeh R, Rudge P, Collinge J, Mead S, Brandner S. Filamentous white matter prion protein deposition is a distinctive feature of multiple inherited prion diseases. Acta Neuropathol Commun 2013; 1:8. [PMID: 24252267 PMCID: PMC4046834 DOI: 10.1186/2051-5960-1-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 03/12/2013] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Sporadic, inherited and acquired prion diseases show distinct histological patterns of abnormal prion protein (PrP) deposits. Many of the inherited prion diseases show striking histological patterns, which often associate with specific mutations. Most reports have focused on the pattern of PrP deposition in the cortical or cerebellar grey matter. RESULTS We observed that the subcortical white matter in inherited prion diseases frequently contained filamentous depositions of abnormal PrP, and we have analysed by immunohistochemistry, immunofluorescence and electron microscopy 35 cases of inherited prion disease seen at the UK National Prion Clinic. We report here that filamentous PrP is abundantly deposited in myelinated fibres in inherited prion diseases, in particular in those with N-terminal mutations. CONCLUSIONS It is possible that the presence of filamentous PrP is related to the pathogenesis of inherited forms, which is different from those sporadic and acquired forms.
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Affiliation(s)
- Lilla Reiniger
- />Division of Neuropathology, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
| | - Ilaria Mirabile
- />Division of Neuropathology, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
| | - Ana Lukic
- />Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London UK
- />National Prion Clinic, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
| | | | | | - Michael Groves
- />Division of Neuropathology, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
| | - Jessica Lowe
- />MRC Prion Unit, UCL Institute of Neurology, London, UK
| | - Ronald Druyeh
- />MRC Prion Unit, UCL Institute of Neurology, London, UK
| | - Peter Rudge
- />National Prion Clinic, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
- />MRC Prion Unit, UCL Institute of Neurology, London, UK
| | - John Collinge
- />Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London UK
- />National Prion Clinic, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
- />MRC Prion Unit, UCL Institute of Neurology, London, UK
| | - Simon Mead
- />National Prion Clinic, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
- />MRC Prion Unit, UCL Institute of Neurology, London, UK
| | - Sebastian Brandner
- />Division of Neuropathology, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
- />Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London UK
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Zhang J, Wang K, Guo Y, Shi Q, Tian C, Chen C, Gao C, Zhang BY, Dong XP. Heat shock protein 70 selectively mediates the degradation of cytosolic PrPs and restores the cytosolic PrP-induced cytotoxicity via a molecular interaction. Virol J 2012; 9:303. [PMID: 23216755 PMCID: PMC3544727 DOI: 10.1186/1743-422x-9-303] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 11/29/2012] [Indexed: 12/12/2022] Open
Abstract
Background Although the aggregation of PrPSc is thought to be crucial for the neuropathology of prion diseases, there is evidence in cultured cells and transgenic mice that neuronal death can be triggered by the accumulation of cytosolic PrPs, leading to the hypothesis that the accumulation of PrPs in the cytosol of neurons may be a primary neurotoxic culprit. Hsp70, a molecular chaperone involved in protein folding/refolding and degradation in the cytoplasm, has a protective effect in some models of neurodegenerative diseases, e.g., Alzheimer’s and Parkinson’s diseases, but its role in prion diseases remains unclear. Results To study the role of Hsp70 in prion diseases, we used immunoprecipitation to first identify a molecular interaction between Hsp70 and PrPs. Using immunofluorescence, we found that Hsp70 colocalized with cytosolic PrPs in HEK293 cells transiently transfected with plasmids for Cyto-PrP and PG14-PrP but not with wild-type PG5-PrP or endoplasmic reticulum (ER)-retained PrPs (3AV-PrP and ER-PrP). Using western blot analysis and apoptosis assays of cultured cells, we found that the overexpression of Hsp70 by transfection or the activation of Hsp70 by geldanamycin selectively mediated the degradation of cytosolic PrPs and restored cytosolic PrP-induced cytotoxicity. Moreover, we found that Hsp70 levels were up-regulated in cells expressing Cyto-PrP and in hamster brains infected with the scrapie agent 263K. Conclusion These data imply that Hsp70 has central role in the metabolism of cytosolic PrPs
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Affiliation(s)
- Jin Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing, 102206, People's Republic of China
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Senatore A, Colleoni S, Verderio C, Restelli E, Morini R, Condliffe S, Bertani I, Mantovani S, Canovi M, Micotti E, Forloni G, Dolphin A, Matteoli M, Gobbi M, Chiesa R. Mutant PrP suppresses glutamatergic neurotransmission in cerebellar granule neurons by impairing membrane delivery of VGCC α(2)δ-1 Subunit. Neuron 2012; 74:300-13. [PMID: 22542184 PMCID: PMC3339322 DOI: 10.1016/j.neuron.2012.02.027] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2012] [Indexed: 01/17/2023]
Abstract
How mutant prion protein (PrP) leads to neurological dysfunction in genetic prion diseases is unknown. Tg(PG14) mice synthesize a misfolded mutant PrP which is partially retained in the neuronal endoplasmic reticulum (ER). As these mice age, they develop ataxia and massive degeneration of cerebellar granule neurons (CGNs). Here, we report that motor behavioral deficits in Tg(PG14) mice emerge before neurodegeneration and are associated with defective glutamate exocytosis from granule neurons due to impaired calcium dynamics. We found that mutant PrP interacts with the voltage-gated calcium channel α(2)δ-1 subunit, which promotes the anterograde trafficking of the channel. Owing to ER retention of mutant PrP, α(2)δ-1 accumulates intracellularly, impairing delivery of the channel complex to the cell surface. Thus, mutant PrP disrupts cerebellar glutamatergic neurotransmission by reducing the number of functional channels in CGNs. These results link intracellular PrP retention to synaptic dysfunction, indicating new modalities of neurotoxicity and potential therapeutic strategies.
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Affiliation(s)
- Assunta Senatore
- Dulbecco Telethon Institute, 20156 Milan, Italy, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
- Department of Neuroscience, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
| | - Simona Colleoni
- Department of Biochemistry and Molecular Pharmacology, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
| | - Claudia Verderio
- Department of Medical Pharmacology and Consiglio Nazionale delle Ricerche Institute of Neuroscience, University of Milan, 20129 Milan, Italy
| | - Elena Restelli
- Dulbecco Telethon Institute, 20156 Milan, Italy, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
- Department of Neuroscience, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
| | - Raffaella Morini
- Department of Medical Pharmacology and Consiglio Nazionale delle Ricerche Institute of Neuroscience, University of Milan, 20129 Milan, Italy
| | - Steven B. Condliffe
- Department of Medical Pharmacology and Consiglio Nazionale delle Ricerche Institute of Neuroscience, University of Milan, 20129 Milan, Italy
| | - Ilaria Bertani
- Dulbecco Telethon Institute, 20156 Milan, Italy, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
- Department of Neuroscience, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
| | - Susanna Mantovani
- Dulbecco Telethon Institute, 20156 Milan, Italy, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
- Department of Neuroscience, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
| | - Mara Canovi
- Department of Biochemistry and Molecular Pharmacology, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
| | - Edoardo Micotti
- Department of Neuroscience, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
| | - Gianluigi Forloni
- Department of Neuroscience, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
| | - Annette C. Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, WC1E6BT London, UK
| | - Michela Matteoli
- Department of Medical Pharmacology and Consiglio Nazionale delle Ricerche Institute of Neuroscience, University of Milan, 20129 Milan, Italy
- Istituto Clinico Humanitas IRCCS, 20089 Milan, Italy
| | - Marco Gobbi
- Department of Biochemistry and Molecular Pharmacology, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
| | - Roberto Chiesa
- Dulbecco Telethon Institute, 20156 Milan, Italy, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
- Department of Neuroscience, “Mario Negri” Institute for Pharmacological Research, 20156 Milan, Italy
- Corresponding author
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12
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Hilker R, Brotchie JM, Chapman J. Pros and cons of a prion-like pathogenesis in Parkinson's disease. BMC Neurol 2011; 11:74. [PMID: 21689433 PMCID: PMC3128002 DOI: 10.1186/1471-2377-11-74] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 06/20/2011] [Indexed: 01/12/2023] Open
Abstract
Background Parkinson's disease (PD) is a slowly progressive neurodegenerative disorder which affects widespread areas of the brainstem, basal ganglia and cerebral cortex. A number of proteins are known to accumulate in parkinsonian brains including ubiquitin and α-synuclein. Prion diseases are sporadic, genetic or infectious disorders with various clinical and histopathological features caused by prion proteins as infectious proteinaceous particles transmitting a misfolded protein configuration through brain tissue. The most important form is Creutzfeldt-Jakob disease which is associated with a self-propagating pathological precursor form of the prion protein that is physiologically widely distributed in the central nervous system. Discussion It has recently been found that α-synuclein may behave similarly to the prion precursor and propagate between cells. The post-mortem proof of α-synuclein containing Lewy bodies in embryonic dopamine cells transplants in PD patient suggests that the misfolded protein might be transmitted from the diseased host to donor neurons reminiscent of prion behavior. The involvement of the basal ganglia and brainstem in the degenerative process are other congruencies between Parkinson's and Creutzfeldt-Jakob disease. However, a number of issues advise caution before categorizing Parkinson's disease as a prion disorder, because clinical appearance, brain imaging, cerebrospinal fluid and neuropathological findings exhibit fundamental differences between both disease entities. Most of all, infectiousness, a crucial hallmark of prion diseases, has never been observed in PD so far. Moreover, the cellular propagation of the prion protein has not been clearly defined and it is, therefore, difficult to assess the molecular similarities between the two disease entities. Summary At the current state of knowledge, the molecular pathways of transmissible pathogenic proteins are not yet fully understood. Their exact involvement in the pathophysiology of prion disorders and neurodegenerative diseases has to be further investigated in order to elucidate a possible overlap between both disease categories that are currently regarded as distinct entities.
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Affiliation(s)
- Ruediger Hilker
- Department of Neurology, Goethe University, Frankfurt/Main, Germany.
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13
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Abstract
Prion diseases in humans and animals are characterized by progressive neurodegeneration and the formation of infectious particles called prions. Both features are intimately linked to a conformational transition of the cellular prion protein (PrP(C)) into aberrantly folded conformers with neurotoxic and self-replicating activities. Interestingly, there is increasing evidence that the infectious and neurotoxic properties of PrP conformers are not necessarily coupled. Transgenic mouse models revealed that some PrP mutants interfere with neuronal function in the absence of infectious prions. Vice versa, propagation of prions can occur without causing neurotoxicity. Consequently, it appears plausible that two partially independent pathways exist, one pathway leading to the propagation of infectious prions and another one that mediates neurotoxic signaling. In this review we will summarize current knowledge of neurotoxic PrP conformers and discuss the role of PrP(C) as a mediator of both stress-protective and neurotoxic signaling cascades.
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Seidel R, Engelhard M. Chemical biology of prion protein: tools to bridge the in vitro/vivo interface. Top Curr Chem (Cham) 2011; 305:199-223. [PMID: 21769714 DOI: 10.1007/128_2011_201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Research on prion protein (PrP) and pathogenic prion has been very intensive because of its importance as model system for neurodegenerative diseases. One important aspect of this research has been the application of chemical biology tools. In this review we describe new developments like native chemical ligation (NCL) and expressed protein ligation (EPL) for the synthesis and semisynthesis of proteins in general and PrP in particular. These techniques allow the synthesis of designed tailor made analogs which can be used in conjunction with modern biophysical methods like fluorescence spectroscopy, solid state Nuclear Magnetic Resonance (ssNMR), and Electron Paramagnetic Resonance (EPR). Another aspect of prion research is concerned with the interaction of PrP with small organic molecules and metals. The results are critically reviewed and put into perspective of their implication for PrP function.
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Affiliation(s)
- Ralf Seidel
- Max Planck Institut für Molekulare Physiologie, Otto-Hahn-Str. 11, 44227, Dortmund, Germany
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15
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Jeffrey M, McGovern G, Sisó S, González L. Cellular and sub-cellular pathology of animal prion diseases: relationship between morphological changes, accumulation of abnormal prion protein and clinical disease. Acta Neuropathol 2011; 121:113-34. [PMID: 20532540 DOI: 10.1007/s00401-010-0700-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 05/04/2010] [Accepted: 05/19/2010] [Indexed: 11/24/2022]
Abstract
The transmissible spongiform encephalopathies (TSEs) or prion diseases of animals are characterised by CNS spongiform change, gliosis and the accumulation of disease-associated forms of prion protein (PrP(d)). Particularly in ruminant prion diseases, a wide range of morphological types of PrP(d) depositions are found in association with neurons and glia. When light microscopic patterns of PrP(d) accumulations are correlated with sub-cellular structure, intracellular PrP(d) co-localises with lysosomes while non-intracellular PrP(d) accumulation co-localises with cell membranes and the extracellular space. Intracellular lysosomal PrP(d) is N-terminally truncated, but the site at which the PrP(d) molecule is cleaved depends on strain and cell type. Different PrP(d) cleavage sites are found for different cells infected with the same agent indicating that not all PrP(d) conformers code for different prion strains. Non-intracellular PrP(d) is full-length and is mainly found on plasma-lemmas of neuronal perikarya and dendrites and glia where it may be associated with scrapie-specific membrane pathology. These membrane changes appear to involve a redirection of the predominant axonal trafficking of normal cellular PrP and an altered endocytosis of PrP(d). PrP(d) is poorly excised from membranes, probably due to increased stabilisation on the membrane of PrP(d) complexed with other membrane ligands. PrP(d) on plasma-lemmas may also be transferred to other cells or released to the extracellular space. It is widely assumed that PrP(d) accumulations cause neurodegenerative changes that lead to clinical disease. However, when different animal prion diseases are considered, neurological deficits do not correlate well with any morphological type of PrP(d) accumulation or perturbation of PrP(d) trafficking. Non-PrP(d)-associated neurodegenerative changes in TSEs include vacuolation, tubulovesicular bodies and terminal axonal degeneration. The last of these correlates well with early neurological disease in mice, but such changes are absent from large animal prion disease. Thus, the proximate cause of clinical disease in animal prion disease is uncertain, but may not involve PrP(d).
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Affiliation(s)
- Martin Jeffrey
- Veterinary Laboratories Agency, Lasswade Laboratory, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, UK.
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16
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Domingo B, Gasset M, Durán-Prado M, Castaño JP, Serrano A, Fischer T, Llopis J. Discrimination between alternate membrane protein topologies in living cells using GFP/YFP tagging and pH exchange. Cell Mol Life Sci 2010; 67:3345-54. [PMID: 20454916 PMCID: PMC11115537 DOI: 10.1007/s00018-010-0386-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 03/30/2010] [Accepted: 04/22/2010] [Indexed: 02/05/2023]
Abstract
Membrane protein function is determined by the relative organization of the protein domains with respect to the membrane. We have experimentally verified the topology of a protein with diverse orientations arising from a single primary sequence (the cellular prion protein, PrP(C)), a novel somatostatin truncated receptor, and the Golgi-associated protein GPBP(91). Tagging with fluorescent proteins (FP) allows location of their expression at the plasma membrane or at endomembranes, but does not inform about their orientation. Exploiting the pH dependency of some FPs, we developed a pH exchange assay in which extracellularly exposed FPs are quenched by application of low pH buffer. We constructed standards to demonstrate and calibrate the assay, and the method was adapted for acidic organelle membrane proteins. This method can serve as a proof of concept, experimentally confirming and/or discriminating in living cells among theoretical topology predictions, providing the proportion of inside/outside orientation for proteins with multiple forms.
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Affiliation(s)
- Beatriz Domingo
- Centro Regional de Investigaciones Biomédicas y Facultad de Medicina, Universidad de Castilla-La Mancha, 02006 Albacete, Spain
| | - María Gasset
- Instituto de Química-Física Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain
| | - Mario Durán-Prado
- Instituto de Parasitología y Biomedicina López-Neyra, CSIC, 18100 Granada, Spain
| | - Justo P. Castaño
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba, Edificio Severo Ochoa, Planta 3. Campus de Rabanales, Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn 06/03), Córdoba, Spain
| | | | | | - Juan Llopis
- Centro Regional de Investigaciones Biomédicas y Facultad de Medicina, Universidad de Castilla-La Mancha, 02006 Albacete, Spain
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17
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Neuron dysfunction is induced by prion protein with an insertional mutation via a Fyn kinase and reversed by sirtuin activation in Caenorhabditis elegans. J Neurosci 2010; 30:5394-403. [PMID: 20392961 DOI: 10.1523/jneurosci.5831-09.2010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Although prion propagation is well understood, the signaling pathways activated by neurotoxic forms of prion protein (PrP) and those able to mitigate pathological phenotypes remain largely unknown. Here, we identify src-2, a Fyn-related kinase, as a gene required for human PrP with an insertional mutation to be neurotoxic in Caenorhabditis elegans, and the longevity modulator sir-2.1/SIRT1, a sirtuin deacetylase, as a modifier of prion neurotoxicity. The expression of octarepeat-expanded PrP in C. elegans mechanosensory neurons led to a progressive loss of response to touch without causing cell death, whereas wild-type PrP expression did not alter behavior. Transgenic PrP molecules showed expression at the plasma membrane, with protein clusters, partial resistance to proteinase K (PK), and protein insolubility detected for mutant PrP. Loss of function (LOF) of src-2 greatly reduced mutant PrP neurotoxicity without reducing PK-resistant PrP levels. Increased sir-2.1 dosage reversed mutant PrP neurotoxicity, whereas sir-2.1 LOF showed aggravation, and these effects did not alter PK-resistant PrP. Resveratrol, a polyphenol known to act through sirtuins for neuroprotection, reversed mutant PrP neurotoxicity in a sir-2.1-dependent manner. Additionally, resveratrol reversed cell death caused by mutant PrP in cerebellar granule neurons from prnp-null mice. These results suggest that Fyn mediates mutant PrP neurotoxicity in addition to its role in cellular PrP signaling and reveal that sirtuin activation mitigates these neurotoxic effects. Sirtuin activators may thus have therapeutic potential to protect from prion neurotoxicity and its effects on intracellular signaling.
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18
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Nachreiner T, Esser M, Tenten V, Troost D, Weis J, Krüttgen A. Novel splice variants of the amyotrophic lateral sclerosis-associated gene VAPB expressed in human tissues. Biochem Biophys Res Commun 2010; 394:703-8. [PMID: 20227395 DOI: 10.1016/j.bbrc.2010.03.055] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2010] [Accepted: 03/09/2010] [Indexed: 02/03/2023]
Abstract
VAPB is a highly conserved integral membrane protein that is ubiquitously expressed in all eukaryotic organisms and located within the membranes of the endoplasmic reticulum (ER). The P56S missense mutation of the VAPB protein is linked to a hereditary form of amyotrophic lateral sclerosis (ALS8), and the pathogenesis of ALS8 has remained enigmatic. We report the cloning of five novel splice variants of the human VAPB gene, all of which are expressed at the mRNA level in the human nervous system. When transfected into human HEK293 or SH-SY5Y cells, two of these variants (VAPB-2 and VAPB-4,5) were readily detectable by immunoblotting whereas two variants (VAPB-3 and VAPB-3,4) became detectable after proteasomal inhibition, a condition commonly found in neurodegenerative diseases. Interestingly, one of these novel VAPB variants, VAPB-2, co-immunoprecipitated with wt-VAPB. However, so far none of these splice variants could be detected by immunoblotting of lysates from selected human tissues, suggesting that in vivo, the proteins translated from the variant VAPB mRNAs are quickly degraded or, alternatively, the expressed proteins are below detection limit of the available antibodies. We speculate that under conditions of proteasomal inhibition, as encountered in many neurodegenerative diseases including ALS, variant VAPB proteins might accumulate in affected cells and contribute to ALS pathogenesis.
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Affiliation(s)
- T Nachreiner
- Institute of Neuropathology, Medical Faculty, RWTH Aachen University, Aachen, Germany
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19
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Solomon IH, Schepker JA, Harris DA. Prion neurotoxicity: insights from prion protein mutants. Curr Issues Mol Biol 2009; 12:51-61. [PMID: 19767650 PMCID: PMC4821541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
The chemical nature of prions and the mechanism by which they propagate are now reasonably well understood. In contrast, much less is known about the identity of the toxic prion protein (PrP) species that are responsible for neuronal death, and the cellular pathways that these forms activate. In addition, the normal, physiological function of cellular PrP (PrP(C)) has remained mysterious, hampering efforts to determine whether loss or alteration of this function contributes to the disease phenotype. Considerable evidence now suggests that aggregation, toxicity, and infectivity are distinct properties of PrP that do no necessarily coincide. In this review, we will discuss several mutant forms of PrP that produce spontaneous neurodegeneration in humans and/or transgenic mice without the formation of infectious PrP(Sc). These include an octapeptide insertional mutation, point mutations that favor synthesis of transmembrane forms of PrP, and deletions encompassing the central domain whose neurotoxicity is antagonized by the presence of wild-type PrP. By isolating the neurotoxic effects of PrP from the formation of infectious prions, these mutants have provided important insights into possible pathogenic mechanisms. These studies suggest that prion neurotoxicity may involve subversion of a cytoprotective activity of PrP(C) via altered signaling events at the plasma membrane.
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Affiliation(s)
- Isaac H Solomon
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Jeffrey M, Goodsir C, McGovern G, Barmada SJ, Medrano AZ, Harris DA. Prion protein with an insertional mutation accumulates on axonal and dendritic plasmalemma and is associated with distinctive ultrastructural changes. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:1208-17. [PMID: 19700753 PMCID: PMC2731139 DOI: 10.2353/ajpath.2009.090125] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/19/2009] [Indexed: 11/20/2022]
Abstract
Prion diseases are fatal neurological diseases characterized by central nervous system deposition of abnormal forms of a membrane glycoprotein designated PrP (prion protein). Tg(PG14) transgenic mice express PrP that harbor a nine-octapeptide insertional mutation homologous to one described in a familial prion disease of humans. Tg(PG14) mice spontaneously develop a fatal neurological illness accompanied by massive apoptosis of cerebellar granule neurons and accumulation of an aggregated and weakly protease-resistant form of PrP that is not infectious. Previous light microscopic analyses of these mice left open questions regarding the subcellular distribution of the mutant protein and the nature of the neuropathological lesions produced. To address these questions, we undertook an immunogold electron microscopic study of Tg(PG14) mice. We found that mutant PrP is localized primarily on the plasma membrane of dendrites and unmyelinated axons in the hippocampus and cerebellum, with little labeling of either neuronal cell bodies or intracellular organelles. PrP deposits were shown to be associated with degenerative changes in dendritic structure. We also describe for the first time marked pathology in myelinated axons, and alterations in the axon/oligodendrocyte interface. Taken together, our results suggest cellular mechanisms by which mutant PrPs produce pathology. In addition, they highlight distinctions between familial and infectious prion disorders at the ultrastructural level that correlate with differences in cellular trafficking of the disease-associated PrP forms.
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Affiliation(s)
- Martin Jeffrey
- Veterinary Laboratories Agency, Lasswade Laboratory, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Scotland.
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21
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Ermolayev V, Cathomen T, Merk J, Friedrich M, Härtig W, Harms GS, Klein MA, Flechsig E. Impaired axonal transport in motor neurons correlates with clinical prion disease. PLoS Pathog 2009; 5:e1000558. [PMID: 19696919 PMCID: PMC2723930 DOI: 10.1371/journal.ppat.1000558] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Accepted: 07/27/2009] [Indexed: 12/29/2022] Open
Abstract
Prion diseases are fatal neurodegenerative disorders causing motor dysfunctions, dementia and neuropathological changes such as spongiosis, astroglyosis and neuronal loss. The chain of events leading to the clinical disease and the role of distinct brain areas are still poorly understood. The role of nervous system integrity and axonal properties in prion pathology are still elusive. There is no evidence of both the functional axonal impairments in vivo and their connection with prion disease. We studied the functional axonal impairments in motor neurons at the onset of clinical prion disease using the combination of tracing as a functional assay for axonal transport with immunohistochemistry experiments. Well-established and novel confocal and ultramicroscopy techniques were used to image and quantify labeled neurons. Despite profound differences in the incubation times, 30% to 45% of neurons in the red nucleus of different mouse lines showed axonal transport impairments at the disease onset bilaterally after intracerebral prion inoculation and unilaterally—after inoculation into the right sciatic nerve. Up to 94% of motor cortex neurons also demonstrated transport defects upon analysis by alternative imaging methods. Our data connect axonal transport impairments with disease symptoms for different prion strains and inoculation routes and establish further insight on the development of prion pathology in vivo. The alterations in localization of the proteins involved in the retrograde axonal transport allow us to propose a mechanism of transport disruption, which involves Rab7-mediated cargo attachment to the dynein-dynactin pathway. These findings suggest novel targets for therapeutic and diagnostic approaches in the early stages of prion disease. For almost a century, prion disease symptoms, such as dementia and motor system defects, have been accompanied with neuropathological hallmarks in the central nervous system. In past decades, discrepancies between neuropathological changes and clinical symptoms showed that the processes triggering the disease remain elusive. We concentrated on the hypothesis that nervous system integrity and axonal properties may play an important role in the disease development. Since motor system defects are typical for prion disease, we investigated the centers of the motor system, red nucleus and hindlimb area of motor cortex. Although intracerebral prion infection led to a 30% to 45% bilateral reduction of labeled neurons in the red nucleus, infection into the right sciatic nerve—the major hindlimb nerve—led to unilateral reduction of labeled neurons in the red nucleus. Up to 94% reduction was found in the neurons of motor cortex hindlimb area. This reduction is probably caused by functional axonal impairments in motor neurons. Prion-induced alterations in protein distribution implicate a mechanism of transport disruption at cargo attachment to the retrograde axonal transport complex. Our work reveals a connection between axonal transport impairments and disease symptoms in vivo, providing further insight in the development of prion pathology and suggesting novel targets for therapeutic and diagnostic approaches.
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Affiliation(s)
- Vladimir Ermolayev
- Molecular Microscopy Group, DFG Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
- Institute of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Toni Cathomen
- Department of Virology, Institute of Infectious Diseases, Charité Medical School, Berlin, Germany
| | - Julia Merk
- Institute of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Mike Friedrich
- Molecular Microscopy Group, DFG Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Wolfgang Härtig
- University of Leipzig, Paul Flechsig Institute for Brain Research, Leipzig, Germany
| | - Gregory S. Harms
- Molecular Microscopy Group, DFG Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
- * E-mail: (GSH); (MAK)
| | - Michael A. Klein
- Institute of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
- * E-mail: (GSH); (MAK)
| | - Eckhard Flechsig
- Institute of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
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Ermolayev V, Friedrich M, Nozadze R, Cathomen T, Klein MA, Harms GS, Flechsig E. Ultramicroscopy reveals axonal transport impairments in cortical motor neurons at prion disease. Biophys J 2009; 96:3390-8. [PMID: 19383482 PMCID: PMC2718265 DOI: 10.1016/j.bpj.2009.01.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 12/02/2008] [Accepted: 01/14/2009] [Indexed: 02/04/2023] Open
Abstract
The functional imaging of neuronal circuits of the central nervous system is crucial for phenotype screenings or investigations of defects in neurodegenerative disorders. Current techniques yield either low penetration depth, yield poor resolution, or are restricted by the age of the animals. Here, we present a novel ultramicroscopy protocol for fluorescence imaging and three-dimensional reconstruction in the central nervous system of adult mice. In combination with tracing as a functional assay for axonal transport, retrogradely labeled descending motor neurons were visualized with >4 mm penetration depth. The analysis of the motor cortex shortly before the onset of clinical prion disease revealed that >80% neurons have functional impairments in axonal transport. Our study provides evidence that prion disease is associated with severe axonal transport defects in the cortical motor neurons and suggests a novel mechanism for prion-mediated neurodegeneration.
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Affiliation(s)
- Vladimir Ermolayev
- Institute of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Mike Friedrich
- Molecular Microscopy Group, Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
| | - Revaz Nozadze
- Molecular Microscopy Group, Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
| | - Toni Cathomen
- Charité Medical School, Institute of Virology, Berlin, Germany
| | - Michael A. Klein
- Institute of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Gregory S. Harms
- Molecular Microscopy Group, Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
| | - Eckhard Flechsig
- Institute of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
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Aggregated, wild-type prion protein causes neurological dysfunction and synaptic abnormalities. J Neurosci 2009; 28:13258-67. [PMID: 19052217 DOI: 10.1523/jneurosci.3109-08.2008] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The neurotoxic forms of the prion protein (PrP) that cause neurodegeneration in prion diseases remain to be conclusively identified. Considerable evidence points to the importance of noninfectious oligomers of PrP in the pathogenic process. In this study, we describe lines of Tg(WT) transgenic mice that over-express wild-type PrP by either approximately 5-fold or approximately 10-fold (depending on whether the transgene array is, respectively, hemizygous or homozygous). Homozygous but not hemizygous Tg(WT) mice develop a spontaneous neurodegenerative illness characterized clinically by tremor and paresis. Both kinds of mice accumulate large numbers of punctate PrP deposits in the molecular layer of the cerebellum as well as in several other brain regions, and they display abnormally enlarged synaptic terminals accompanied by a dramatic proliferation of membranous structures. The over-expressed PrP in Tg(WT) mice assembles into an insoluble form that is mildly protease-resistant and is recognizable by aggregation-specific antibodies, but that is not infectious in transmission experiments. Together, our results demonstrate that noninfectious aggregates of wild-type PrP are neurotoxic, particularly to synapses, and they suggest common pathogenic mechanisms shared by prion diseases and nontransmissible neurodegenerative disorders associated with protein misfolding.
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Bakota L, Brandt R. Chapter 2 Live‐Cell Imaging in the Study of Neurodegeneration. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 276:49-103. [DOI: 10.1016/s1937-6448(09)76002-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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