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Verde F, Aiello EN, Adobbati L, Poletti B, Solca F, Tiloca C, Sangalli D, Maranzano A, Muscio C, Ratti A, Zago S, Ticozzi N, Frisoni GB, Silani V. Coexistence of Amyotrophic Lateral Sclerosis and Alzheimer's Disease: Case Report and Review of the Literature. J Alzheimers Dis 2023; 95:1383-1399. [PMID: 37694369 DOI: 10.3233/jad-230562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
We describe a case of amyotrophic lateral sclerosis (ALS) associated with Alzheimer's disease (AD) and review the literature about the coexistence of the two entities, highlighting the following: mean age at onset is 63.8 years, with slight female predominance; ALS tends to manifest after cognitive impairment and often begins in the bulbar region; average disease duration is 3 years; cognitive phenotype is mostly amnestic; the pattern of brain involvement is, in most cases, consistent with AD. Our case and the reviewed ones suggest that patients with ALS and dementia lacking unequivocal features of FTD should undergo additional examinations in order to recognize AD.
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Affiliation(s)
- Federico Verde
- Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
- Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, Università degli Studi di Milano, Milan, Italy
| | - Edoardo Nicolò Aiello
- Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Laura Adobbati
- Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Barbara Poletti
- Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
- Department of Oncology and Hemato-Oncology, Università degli Studi di Milano, Milan, Italy
| | - Federica Solca
- Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Cinzia Tiloca
- Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Davide Sangalli
- Department of Neurology and Stroke Unit, Azienda Socio Sanitaria Territoriale Lecco, Lecco, Italy
| | - Alessio Maranzano
- Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Cristina Muscio
- Neurology-5 (Neuropathology) Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Antonia Ratti
- Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Stefano Zago
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Nicola Ticozzi
- Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
- Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, Università degli Studi di Milano, Milan, Italy
| | - Giovanni Battista Frisoni
- Memory Clinic and LANVIE - Laboratory of Neuroimaging of Aging, University Hospitals and University of Geneva, Geneva, Switzerland
| | - Vincenzo Silani
- Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
- Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, Università degli Studi di Milano, Milan, Italy
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Lim ZQ, Ng QY, Oo Y, Chu JJH, Ng SY, Sze SK, Alonso S. Enterovirus-A71 exploits peripherin and Rac1 to invade the central nervous system. EMBO Rep 2021; 22:e51777. [PMID: 33871166 DOI: 10.15252/embr.202051777] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 03/02/2021] [Accepted: 03/10/2021] [Indexed: 12/28/2022] Open
Abstract
Enterovirus-A71 (EV-A71) has been associated with severe neurological forms of hand, foot, and mouth disease (HFMD). EV-A71 infects motor neurons at neuromuscular junctions (NMJs) to invade the central nervous system (CNS). Here, we investigate the role of peripherin (PRPH) during EV-A71 infection, a type III intermediate neurofilament involved in neurodegenerative conditions. In mice infected with EV-A71, PRPH co-localizes with viral particles in the muscles at NMJs and in the spinal cord. In motor neuron-like and neuroblastoma cell lines, surface-expressed PRPH facilitates viral entry, while intracellular PRPH influences viral genome replication through interactions with structural and non-structural viral components. Importantly, PRPH does not play a role during infection with coxsackievirus A16, another causative agent of HFMD rarely associated with neurological complications, suggesting that EV-A71 ability to exploit PRPH represents a unique attribute for successful CNS invasion. Finally, we show that EV-A71 also exploits some of the many PRPH-interacting partners. Of these, small GTP-binding protein Rac1 represents a potential druggable host target to limit neuroinvasion of EV-A71.
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Affiliation(s)
- Ze Qin Lim
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Qing Yong Ng
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Yukei Oo
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Justin Jang Hann Chu
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Shi Yan Ng
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore
| | - Siu Kwan Sze
- Proteomics and Mass Spectrometry Services Core Facility, School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Sylvie Alonso
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
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Does SCFD1 rs10139154 Polymorphism Decrease Alzheimer’s Disease Risk? J Mol Neurosci 2019; 69:343-350. [DOI: 10.1007/s12031-019-01363-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 06/25/2019] [Indexed: 12/14/2022]
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Alonso R, Pisa D, Fernández-Fernández AM, Rábano A, Carrasco L. Fungal infection in neural tissue of patients with amyotrophic lateral sclerosis. Neurobiol Dis 2017; 108:249-260. [DOI: 10.1016/j.nbd.2017.09.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/24/2017] [Accepted: 09/03/2017] [Indexed: 12/11/2022] Open
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Ise H, Yamasaki S, Sueyoshi K, Miura Y. Elucidation of GlcNAc-binding properties of type III intermediate filament proteins, using GlcNAc-bearing polymers. Genes Cells 2017; 22:900-917. [PMID: 28898551 DOI: 10.1111/gtc.12535] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 08/15/2017] [Indexed: 12/26/2022]
Abstract
Vimentin, desmin, glial fibrillary acidic protein (GFAP) and peripherin belong to type III intermediate filament family and are expressed in mesenchymal cells, skeletal muscle cells, astrocytes and peripheral neurons, respectively. Vimentin and desmin possess N-acetyl-d-glucosamine (GlcNAc)-binding properties on cell surfaces. The rod II domain of these proteins is a GlcNAc-binding site, which also exists in GFAP and peripherin. However, the GlcNAc-binding activities and behaviors of these proteins remain unclear. Here, we characterized the interaction and binding behaviors of these proteins, using various well-defined GlcNAc-bearing polymers synthesized by radical polymerization with a reversible addition-fragmentation chain transfer reagent. The small GlcNAc-bearing polymers strongly interacted with HeLa cells through vimentin expressed on the cell surface and interacted with vimentin-, desmin-, GFAP- and peripherin-transfected vimentin-deficient HeLa cells. These proteins present high affinity to GlcNAc-bearing polymers, as shown by surface plasmon resonance. These results show that type III intermediate filament proteins possess GlcNAc-binding activities on cell surfaces. These findings provide important insights into novel cellular functions and physiological significance of type III intermediate filaments.
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Affiliation(s)
- Hirohiko Ise
- Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Sadanori Yamasaki
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Kazuaki Sueyoshi
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Yoshiko Miura
- Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
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Genetic compendium of 1511 human brains available through the UK Medical Research Council Brain Banks Network Resource. Genome Res 2016; 27:165-173. [PMID: 28003435 PMCID: PMC5204341 DOI: 10.1101/gr.210609.116] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 11/10/2016] [Indexed: 12/28/2022]
Abstract
Given the central role of genetic factors in the pathogenesis of common neurodegenerative disorders, it is critical that mechanistic studies in human tissue are interpreted in a genetically enlightened context. To address this, we performed exome sequencing and copy number variant analysis on 1511 frozen human brains with a diagnosis of Alzheimer's disease (AD, n = 289), frontotemporal dementia/amyotrophic lateral sclerosis (FTD/ALS, n = 252), Creutzfeldt-Jakob disease (CJD, n = 239), Parkinson's disease (PD, n = 39), dementia with Lewy bodies (DLB, n = 58), other neurodegenerative, vascular, or neurogenetic disorders (n = 266), and controls with no significant neuropathology (n = 368). Genomic DNA was extracted from brain tissue in all cases before exome sequencing (Illumina Nextera 62 Mb capture) with variants called by FreeBayes; copy number variant (CNV) analysis (Illumina HumanOmniExpress-12 BeadChip); C9orf72 repeat expansion detection; and APOE genotyping. Established or likely pathogenic heterozygous, compound heterozygous, or homozygous variants, together with the C9orf72 hexanucleotide repeat expansions and a copy number gain of APP, were found in 61 brains. In addition to known risk alleles in 349 brains (23.9% of 1461 undergoing exome sequencing), we saw an association between rare variants in GRN and DLB. Rare CNVs were found in <1.5% of brains, including copy number gains of PRPH that were overrepresented in AD. Clinical, pathological, and genetic data are available, enabling the retrieval of specific frozen brains through the UK Medical Research Council Brain Banks Network. This allows direct access to pathological and control human brain tissue based on an individual's genetic architecture, thus enabling the functional validation of known genetic risk factors and potentially pathogenic alleles identified in future studies.
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Muresan V, Ladescu Muresan Z. Shared Molecular Mechanisms in Alzheimer's Disease and Amyotrophic Lateral Sclerosis: Neurofilament-Dependent Transport of sAPP, FUS, TDP-43 and SOD1, with Endoplasmic Reticulum-Like Tubules. NEURODEGENER DIS 2015; 16:55-61. [PMID: 26605911 DOI: 10.1159/000439256] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/07/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Amyotrophic lateral sclerosis (ALS), a debilitating neurodegenerative disorder of the motor neurons, leads to the disorganization of the neurofilament (NF) cytoskeleton and - ultimately - the deterioration of the neuromuscular junction. Some familial cases of ALS are caused by mutated FUS, TDP-43 or SOD1; it is thought that the mutated proteins inflict pathology either by gain or loss of function. The proper function of the neuromuscular junction requires sAPP, a soluble proteolytic fragment of the amyloid-β precursor protein (APP) - a transmembrane protein implicated in the pathology of Alzheimer's disease (AD). Whether sAPP, FUS, TDP-43 and SOD1 are mechanistically linked in a common pathway deregulated in both AD and ALS is not known. SUMMARY We show that sAPP, TDP-43, FUS and SOD1 are transported to neurite terminals by a mechanism that involves endoplasmic reticulum (ER)-like tubules and requires peripherin NFs. The transport of these proteins, and the translocation of the ER protein reticulon 4 (Rtn4) into neurites was studied in CAD cells, a brainstem-derived neuronal cell line highly relevant to AD and ALS. We show that a significant fraction of sAPP is generated in the soma and accumulates in a juxtanuclear ER subdomain. In neurites, sAPP localizes to Rtn4-positive ER-like tubules that extend from the soma into the growth cone and colocalizes with peripherin NFs. Knocking down peripherin disrupts the NF network and diminishes the accumulation of sAPP, TDP-43, FUS, SOD1 and Rtn4 at terminals. KEY MESSAGES We propose that the impediment of a common, ER-mediated mechanism of transport of sAPP, TDP-43, FUS and SOD1, caused by a disrupted NF network, could be part of the mechanisms leading to AD and ALS.
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Affiliation(s)
- Virgil Muresan
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, N.J., USA
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Tan RH, Kril JJ, Fatima M, McGeachie A, McCann H, Shepherd C, Forrest SL, Affleck A, Kwok JBJ, Hodges JR, Kiernan MC, Halliday GM. TDP-43 proteinopathies: pathological identification of brain regions differentiating clinical phenotypes. Brain 2015; 138:3110-22. [PMID: 26231953 DOI: 10.1093/brain/awv220] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 06/14/2015] [Indexed: 11/14/2022] Open
Abstract
The pathological sequestration of TAR DNA-binding protein 43 (TDP-43, encoded by TARDBP) into cytoplasmic pathological inclusions characterizes the distinct clinical syndromes of amyotrophic lateral sclerosis and behavioural variant frontotemporal dementia, while also co-occurring in a proportion of patients with Alzheimer's disease, suggesting that the regional concentration of TDP-43 pathology has most relevance to specific clinical phenotypes. This has been reflected in the three different pathological staging schemes for TDP-43 pathology in these different clinical syndromes, with none of these staging schemes including a preclinical phase similar to that which has proven beneficial in other neurodegenerative diseases. To apply each of these three staging schemes for TDP-43 pathology, the clinical phenotype must be known undermining the potential predictive value of the pathological examination. The present study set out to test whether a more unified approach could accurately predict clinical phenotypes based solely on the regional presence and severity of TDP-43 pathology. The selection of brain regions of interest was based on key regions routinely sampled for neuropathological assessment under current consensus criteria that have also been used in the three TDP-43 staging schemes. The severity of TDP-43 pathology in these regions of interest was assessed in four clinicopathological phenotypes: amyotrophic lateral sclerosis (n = 27, 47-78 years, 15 males), behavioural variant frontotemporal dementia (n = 15, 49-82 years, seven males), Alzheimer's disease (n = 26, 51-90 years, 11 males) and cognitively normal elderly individuals (n = 17, 80-103 years, nine males). Our results demonstrate that the presence of TDP-43 in the hypoglossal nucleus discriminates patients with amyotrophic lateral sclerosis with an accuracy of 98%. The severity of TDP-43 deposited in the anterior cingulate cortex identifies patients with behavioural variant frontotemporal dementia with an accuracy of 99%. This identification of regional pathology associated with distinct clinical phenotypes suggests key regions on which probabilistic pathological criteria, similar to those currently available for Alzheimer's disease and dementia with Lewy bodies, can be developed for TDP-43 proteinopathies. We propose and validate a simplified probabilistic statement that involves grading the presence of TDP-43 in the hypoglossal nucleus and the severity of TDP-43 in the anterior cingulate for the pathological identification of TDP-43 proteinopathy cases with clinical amyotrophic lateral sclerosis and behavioural variant frontotemporal dementia.
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Affiliation(s)
- Rachel H Tan
- 1 Neuroscience Research Australia, Sydney, Australia 2 UNSW Medicine, University of New South Wales, Sydney, Australia
| | - Jillian J Kril
- 3 Discipline of Pathology, Sydney Medical School, The University of Sydney, Australia 4 Discipline of Medicine, Sydney Medical School, The University of Sydney, Australia
| | - Manaal Fatima
- 1 Neuroscience Research Australia, Sydney, Australia 2 UNSW Medicine, University of New South Wales, Sydney, Australia 3 Discipline of Pathology, Sydney Medical School, The University of Sydney, Australia
| | - Andrew McGeachie
- 1 Neuroscience Research Australia, Sydney, Australia 2 UNSW Medicine, University of New South Wales, Sydney, Australia
| | | | - Claire Shepherd
- 1 Neuroscience Research Australia, Sydney, Australia 2 UNSW Medicine, University of New South Wales, Sydney, Australia
| | - Shelley L Forrest
- 3 Discipline of Pathology, Sydney Medical School, The University of Sydney, Australia
| | - Andrew Affleck
- 1 Neuroscience Research Australia, Sydney, Australia 2 UNSW Medicine, University of New South Wales, Sydney, Australia
| | - John B J Kwok
- 1 Neuroscience Research Australia, Sydney, Australia 2 UNSW Medicine, University of New South Wales, Sydney, Australia
| | - John R Hodges
- 1 Neuroscience Research Australia, Sydney, Australia 2 UNSW Medicine, University of New South Wales, Sydney, Australia 5 ARC Centre of Excellence in Cognition and its Disorders, Sydney, Australia
| | - Matthew C Kiernan
- 6 Brain and Mind Research Institute, Sydney Medical School, The University of Sydney, Australia
| | - Glenda M Halliday
- 1 Neuroscience Research Australia, Sydney, Australia 2 UNSW Medicine, University of New South Wales, Sydney, Australia
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Alonso R, Pisa D, Marina AI, Morato E, Rábano A, Rodal I, Carrasco L. Evidence for fungal infection in cerebrospinal fluid and brain tissue from patients with amyotrophic lateral sclerosis. Int J Biol Sci 2015; 11:546-58. [PMID: 25892962 PMCID: PMC4400386 DOI: 10.7150/ijbs.11084] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/10/2015] [Indexed: 12/14/2022] Open
Abstract
Among neurogenerative diseases, amyotrophic lateral sclerosis (ALS) is a fatal illness characterized by a progressive motor neuron dysfunction in the motor cortex, brainstem and spinal cord. ALS is the most common form of motor neuron disease; yet, to date, the exact etiology of ALS remains unknown. In the present work, we have explored the possibility of fungal infection in cerebrospinal fluid (CSF) and in brain tissue from ALS patients. Fungal antigens, as well as DNA from several fungi, were detected in CSF from ALS patients. Additionally, examination of brain sections from the frontal cortex of ALS patients revealed the existence of immunopositive fungal antigens comprising punctate bodies in the cytoplasm of some neurons. Fungal DNA was also detected in brain tissue using PCR analysis, uncovering the presence of several fungal species. Finally, proteomic analyses of brain tissue demonstrated the occurrence of several fungal peptides. Collectively, our observations provide compelling evidence of fungal infection in the ALS patients analyzed, suggesting that this infection may play a part in the etiology of the disease or may constitute a risk factor for these patients.
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Affiliation(s)
- Ruth Alonso
- 1. Centro de Biología Molecular "Severo Ochoa". c/Nicolás Cabrera, 1. Universidad Autónoma de Madrid. Cantoblanco. 28049 Madrid. Spain
| | - Diana Pisa
- 1. Centro de Biología Molecular "Severo Ochoa". c/Nicolás Cabrera, 1. Universidad Autónoma de Madrid. Cantoblanco. 28049 Madrid. Spain
| | - Ana Isabel Marina
- 1. Centro de Biología Molecular "Severo Ochoa". c/Nicolás Cabrera, 1. Universidad Autónoma de Madrid. Cantoblanco. 28049 Madrid. Spain
| | - Esperanza Morato
- 1. Centro de Biología Molecular "Severo Ochoa". c/Nicolás Cabrera, 1. Universidad Autónoma de Madrid. Cantoblanco. 28049 Madrid. Spain
| | - Alberto Rábano
- 2. Department of Neuropathology and Tissue Bank, Unidad de Investigación Proyecto Alzheimer, Fundación CIEN, Instituto de Salud Carlos III, Madrid. Spain
| | - Izaskun Rodal
- 2. Department of Neuropathology and Tissue Bank, Unidad de Investigación Proyecto Alzheimer, Fundación CIEN, Instituto de Salud Carlos III, Madrid. Spain
| | - Luis Carrasco
- 1. Centro de Biología Molecular "Severo Ochoa". c/Nicolás Cabrera, 1. Universidad Autónoma de Madrid. Cantoblanco. 28049 Madrid. Spain
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Muresan V, Ladescu Muresan Z. Amyloid-β precursor protein: Multiple fragments, numerous transport routes and mechanisms. Exp Cell Res 2015; 334:45-53. [PMID: 25573596 DOI: 10.1016/j.yexcr.2014.12.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 12/26/2014] [Indexed: 02/01/2023]
Abstract
This review provides insight into the intraneuronal transport of the Amyloid-β Precursor Protein (APP), the prototype of an extensively posttranslationally modified and proteolytically cleaved transmembrane protein. Uncovering the intricacies of APP transport proves to be a challenging endeavor of cell biology research, deserving increased priority, since APP is at the core of the pathogenic process in Alzheimer's disease. After being synthesized in the endoplasmic reticulum in the neuronal soma, APP enters the intracellular transport along the secretory, endocytic, and recycling routes. Along these routes, APP undergoes cleavage into defined sets of fragments, which themselves are transported - mostly independently - to distinct sites in neurons, where they exert their functions. We review the currently known routes and mechanisms of transport of full-length APP, and of APP fragments, commenting largely on the experimental challenges posed by studying transport of extensively cleaved proteins. The review emphasizes the interrelationships between the proteolytic and posttranslational modifications, the intracellular transport, and the functions of the APP species. A goal remaining to be addressed in the future is the incorporation of the various views on APP transport into a coherent picture. In this review, the disease context is only marginally addressed; the focus is on the basic biology of APP transport under normal conditions. As shown, the studies of APP transport uncovered numerous mechanisms of transport, some of them conventional, and others, novel, awaiting exploration.
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Affiliation(s)
- Virgil Muresan
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07101-1709, USA.
| | - Zoia Ladescu Muresan
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07101-1709, USA.
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Moloney EB, de Winter F, Verhaagen J. ALS as a distal axonopathy: molecular mechanisms affecting neuromuscular junction stability in the presymptomatic stages of the disease. Front Neurosci 2014; 8:252. [PMID: 25177267 PMCID: PMC4132373 DOI: 10.3389/fnins.2014.00252] [Citation(s) in RCA: 217] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/29/2014] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is being redefined as a distal axonopathy, in that many molecular changes influencing motor neuron degeneration occur at the neuromuscular junction (NMJ) at very early stages of the disease prior to symptom onset. A huge variety of genetic and environmental causes have been associated with ALS, and interestingly, although the cause of the disease can differ, both sporadic and familial forms of ALS show a remarkable similarity in terms of disease progression and clinical manifestation. The NMJ is a highly specialized synapse, allowing for controlled signaling between muscle and nerve necessary for skeletal muscle function. In this review we will evaluate the clinical, animal experimental and cellular/molecular evidence that supports the idea of ALS as a distal axonopathy. We will discuss the early molecular mechanisms that occur at the NMJ, which alter the functional abilities of the NMJ. Specifically, we focus on the role of axon guidance molecules on the stability of the cytoskeleton and how these molecules may directly influence the cells of the NMJ in a way that may initiate or facilitate the dismantling of the neuromuscular synapse in the presymptomatic stages of ALS.
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Affiliation(s)
- Elizabeth B. Moloney
- Department of Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and ScienceAmsterdam, Netherlands
| | - Fred de Winter
- Department of Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and ScienceAmsterdam, Netherlands
- Department of Neurosurgery, Leiden University Medical CentreLeiden, Netherlands
| | - Joost Verhaagen
- Department of Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and ScienceAmsterdam, Netherlands
- Centre for Neurogenomics and Cognitive Research, Vrije Universiteit AmsterdamAmsterdam, Netherlands
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Villegas C, Muresan V, Ladescu Muresan Z. Dual-tagged amyloid-β precursor protein reveals distinct transport pathways of its N- and C-terminal fragments. Hum Mol Genet 2013; 23:1631-43. [PMID: 24203698 DOI: 10.1093/hmg/ddt555] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The amyloid-β precursor protein (APP), a type I transmembrane protein genetically associated with Alzheimer's disease, has a complex biology that includes proteolytic processing into potentially toxic fragments, extensive trafficking and multiple, yet poorly-defined functions. We recently proposed that a significant fraction of APP is proteolytically cleaved in the neuronal soma into N- and C-terminal fragments (NTFs and CTFs), which then target independently of each other to separate destinations in the cell. Here, we prove this concept with live imaging and immunolocalization of two dual, N- and C-termini-tagged APP constructs: CFP-APP-YFP [containing the fluorescent tags, cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP)] and FLAG-APP-Myc. When expressed at low levels in neuronal cells, these constructs are processed into differently tagged NTFs and CTFs that reveal distinct distributions and characteristics of transport. Like the endogenous N- and C-terminal epitopes of APP, the FLAG-tagged NTFs are present in trains of vesicles and tubules that localize to short filaments, which often immunostain for acetylated tubulin, whereas the Myc-tagged CTFs are detected on randomly distributed vesicle-like structures. The experimental treatments that selectively destabilize the acetylated microtubules abrogate the distribution of NTFs along filaments, without altering the random distribution of CTFs. These results indicate that the NTFs and CTFs are recruited to distinct transport pathways and reach separate destinations in neurons, where they likely accomplish functions independent of the parental, full-length APP. They also point to a compartment associated with acetylated microtubules in the neuronal soma--not the neurite terminals--as a major site of APP cleavage, and segregation of NTFs from CTFs.
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Affiliation(s)
- Christine Villegas
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07101-1709, USA
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