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Courte J, Le NA, Pan T, Bousset L, Melki R, Villard C, Peyrin JM. Synapses do not facilitate prion-like transfer of alpha-synuclein: a quantitative study in reconstructed unidirectional neural networks. Cell Mol Life Sci 2023; 80:284. [PMID: 37688644 PMCID: PMC10492778 DOI: 10.1007/s00018-023-04915-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 07/11/2023] [Accepted: 08/07/2023] [Indexed: 09/11/2023]
Abstract
Alpha-synuclein (aSyn) aggregation spreads between cells and underlies the progression of neuronal lesions in the brain of patients with synucleinopathies such as Parkinson's diseases. The mechanisms of cell-to-cell propagation of aggregates, which dictate how aggregation progresses at the network level, remain poorly understood. Notably, while prion and prion-like spreading is often simplistically envisioned as a "domino-like" spreading scenario where connected neurons sequentially propagate protein aggregation to each other, the reality is likely to be more nuanced. Here, we demonstrate that the spreading of preformed aSyn aggregates is a limited process that occurs through molecular sieving of large aSyn seeds. We further show that this process is not facilitated by synaptic connections. This was achieved through the development and characterization of a new microfluidic platform that allows reconstruction of binary fully oriented neuronal networks in vitro with no unwanted backward connections, and through the careful quantification of fluorescent aSyn aggregates spreading between neurons. While this allowed us for the first time to extract quantitative data of protein seeds dissemination along neural pathways, our data suggest that prion-like dissemination of proteinopathic seeding aggregates occurs very progressively and leads to highly compartmentalized pattern of protein seeding in neural networks.
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Affiliation(s)
- Josquin Courte
- Faculté des Sciences et Technologie, Institut de Biologie Paris Seine, Sorbonne Universités, CNRS UMR 8246, INSERM U1130, Neurosciences Paris Seine, 75005 Paris, France
- Institut Curie, CNRS UMR 168, Université PSL, Sorbonne Universités, 75005 Paris, France
| | - Ngoc Anh Le
- Faculté des Sciences et Technologie, Institut de Biologie Paris Seine, Sorbonne Universités, CNRS UMR 8246, INSERM U1130, Neurosciences Paris Seine, 75005 Paris, France
| | - Teng Pan
- Faculté des Sciences et Technologie, Institut de Biologie Paris Seine, Sorbonne Universités, CNRS UMR 8246, INSERM U1130, Neurosciences Paris Seine, 75005 Paris, France
| | - Luc Bousset
- Institut François Jacob, (MIRCen), CEA and Laboratory of Neurodegenerative Diseases, CNRS, 92260 Fontenay-Aux-Roses, France
| | - Ronald Melki
- Institut François Jacob, (MIRCen), CEA and Laboratory of Neurodegenerative Diseases, CNRS, 92260 Fontenay-Aux-Roses, France
| | - Catherine Villard
- Institut Curie, CNRS UMR 168, Université PSL, Sorbonne Universités, 75005 Paris, France
| | - Jean-Michel Peyrin
- Faculté des Sciences et Technologie, Institut de Biologie Paris Seine, Sorbonne Universités, CNRS UMR 8246, INSERM U1130, Neurosciences Paris Seine, 75005 Paris, France
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2
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Tabeeva G, Silachev D, Vishnyakova P, Asaturova A, Fatkhudinov T, Smetnik A, Dumanovskaya M. The Therapeutic Potential of Multipotent Mesenchymal Stromal Cell-Derived Extracellular Vesicles in Endometrial Regeneration. Int J Mol Sci 2023; 24:ijms24119431. [PMID: 37298382 DOI: 10.3390/ijms24119431] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 05/24/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Disruption of endometrial regeneration, fibrosis formation, and intrauterine adhesions underlie the development of "thin" endometrium and/or Asherman's syndrome (AS) and are a common cause of infertility and a high risk for adverse obstetric outcomes. The methods used (surgical adhesiolysis, anti-adhesive agents, and hormonal therapy) do not allow restoration of the regenerative properties of the endometrium. The experience gained today with cell therapy using multipotent mesenchymal stromal cells (MMSCs) proves their high regenerative and proliferative properties in tissue damage. Their contribution to regenerative processes is still poorly understood. One of these mechanisms is based on the paracrine effects of MMSCs associated with the stimulation of cells of the microenvironment by secreting extracellular vesicles (EVs) into the extracellular space. EVs, whose source is MMSCs, are able to stimulate progenitor cells and stem cells in damaged tissues and exert cytoprotective, antiapoptotic, and angiogenic effects. This review described the regulatory mechanisms of endometrial regeneration, pathological conditions associated with a decrease in endometrial regeneration, and it presented the available data from studies on the effect of MMSCs and their EVs on endometrial repair processes, and the involvement of EVs in human reproductive processes at the level of implantation and embryogenesis.
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Affiliation(s)
- Gyuzyal Tabeeva
- National Medical Research Center for Obstetrics, Gynecology and Perinatology Named after Academician V.I. Kulakov of Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia
| | - Denis Silachev
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Polina Vishnyakova
- National Medical Research Center for Obstetrics, Gynecology and Perinatology Named after Academician V.I. Kulakov of Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia
- Research Institute of Molecular and Cellular Medicine, Peoples' Friendship University of Russia (RUDN University), 117198 Moscow, Russia
| | - Alexandra Asaturova
- National Medical Research Center for Obstetrics, Gynecology and Perinatology Named after Academician V.I. Kulakov of Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia
| | - Timur Fatkhudinov
- Research Institute of Molecular and Cellular Medicine, Peoples' Friendship University of Russia (RUDN University), 117198 Moscow, Russia
- Avtsyn Research Institute of Human Morphology of Federal State Budgetary Scientific Institution Petrovsky National Research Centre of Surgery, 117418 Moscow, Russia
| | - Antonina Smetnik
- National Medical Research Center for Obstetrics, Gynecology and Perinatology Named after Academician V.I. Kulakov of Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia
| | - Madina Dumanovskaya
- National Medical Research Center for Obstetrics, Gynecology and Perinatology Named after Academician V.I. Kulakov of Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia
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3
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Gosset P, Camu W, Raoul C, Mezghrani A. Prionoids in amyotrophic lateral sclerosis. Brain Commun 2022; 4:fcac145. [PMID: 35783556 PMCID: PMC9242622 DOI: 10.1093/braincomms/fcac145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/16/2022] [Accepted: 06/01/2022] [Indexed: 12/20/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is the third most frequent neurodegenerative disease after Alzheimer’s and Parkinson’s disease. ALS is characterized by the selective and progressive loss of motoneurons in the spinal cord, brainstem and cerebral cortex. Clinical manifestations typically occur in midlife and start with focal muscle weakness, followed by the rapid and progressive wasting of muscles and subsequent paralysis. As with other neurodegenerative diseases, the condition typically begins at an initial point and then spreads along neuroanatomical tracts. This feature of disease progression suggests the spreading of prion-like proteins called prionoids in the affected tissues, which is similar to the spread of prion observed in Creutzfeldt-Jakob disease. Intensive research over the last decade has proposed the ALS-causing gene products Cu/Zn superoxide dismutase 1, TAR DNA-binding protein of 43 kDa, and fused in sarcoma as very plausible prionoids contributing to the spread of the pathology. In this review, we will discuss the molecular and cellular mechanisms leading to the propagation of these prionoids in ALS.
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Affiliation(s)
- Philippe Gosset
- INM, Univ Montpellier, INSERM, CNRS, Montpellier 34095, France
| | - William Camu
- INM, Univ Montpellier, INSERM, CNRS, Montpellier 34095, France
| | - Cedric Raoul
- INM, Univ Montpellier, INSERM, CNRS, Montpellier 34095, France
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4
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Cuesta FA, Guerberoff G, Rojo ÁL. Bernoulli and binomial proliferation on evolutionary graphs. J Theor Biol 2022; 534:110942. [PMID: 34717934 DOI: 10.1016/j.jtbi.2021.110942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022]
Abstract
In this paper we introduce random proliferation models on graphs. We consider two types of particles: type-1/mutant/invader/red particles proliferates on a population of type-2/wild-type/resident/blue particles. Unlike the well-known Moran model on graphs -as introduced in Lieberman et al. (2005)-, type-1 particles can occupy in a single iteration several neighbouring sites previously occupied by type-2 particles. Two variants are considered, depending on the random distribution involving the proliferation mechanism: Bernoulli and binomial proliferation. By comparison with fixation probability of type-1 particles in the Moran process, critical parameters are introduced. Properties of proliferation are studied and some particular cases are analytically solved. Finally, by updating the parameters that drive the processes through a density-dependent mechanism, it is possible to capture additional relevant features as fluctuating waves of type-1 particles over long periods of time. In fact, the models can be adapted to tackle more general, complex and realistic situations.
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Affiliation(s)
- Fernando Alcalde Cuesta
- Instituto de Matemáticas, Universidad de Santiago de Compostela, Santiago de Compostela E-15782, Spain
| | - Gustavo Guerberoff
- Instituto de Matemática y Estadística Rafael Laguardia, Facultad de Ingeniería, Universidad de la República, J. Herrera y Reissig 565, Montevideo C.P.11300, Uruguay.
| | - Álvaro Lozano Rojo
- Departamento de Matemáticas, Instituto Universitario de Matemáticas y Aplicaciones (IUMA), Universidad de Zaragoza, Pedro Cerbuna, 12, Zaragoza E-50009, Spain
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5
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Haidar MA, Ibeh S, Shakkour Z, Reslan MA, Nwaiwu J, Moqidem YA, Sader G, Nickles RG, Babale I, Jaffa AA, Salama M, Shaito A, Kobeissy F. Crosstalk between Microglia and Neurons in Neurotrauma: An Overview of the Underlying Mechanisms. Curr Neuropharmacol 2022; 20:2050-2065. [PMID: 34856905 PMCID: PMC9886840 DOI: 10.2174/1570159x19666211202123322] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 11/12/2021] [Accepted: 11/18/2021] [Indexed: 11/22/2022] Open
Abstract
Microglia are the resident immune cells of the brain and play a crucial role in housekeeping and maintaining homeostasis of the brain microenvironment. Upon injury or disease, microglial cells become activated, at least partly, via signals initiated by injured neurons. Activated microglia, thereby, contribute to both neuroprotection and neuroinflammation. However, sustained microglial activation initiates a chronic neuroinflammatory response which can disturb neuronal health and disrupt communications between neurons and microglia. Thus, microglia-neuron crosstalk is critical in a healthy brain as well as during states of injury or disease. As most studies focus on how neurons and microglia act in isolation during neurotrauma, there is a need to understand the interplay between these cells in brain pathophysiology. This review highlights how neurons and microglia reciprocally communicate under physiological conditions and during brain injury and disease. Furthermore, the modes of microglia-neuron communication are exposed, focusing on cell-contact dependent signaling and communication by the secretion of soluble factors like cytokines and growth factors. In addition, it has been discussed that how microglia-neuron interactions could exert either beneficial neurotrophic effects or pathologic proinflammatory responses. We further explore how aberrations in microglia-neuron crosstalk may be involved in central nervous system (CNS) anomalies, namely traumatic brain injury (TBI), neurodegeneration, and ischemic stroke. A clear understanding of how the microglia-neuron crosstalk contributes to the pathogenesis of brain pathologies may offer novel therapeutic avenues of brain trauma treatment.
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Affiliation(s)
- Muhammad Ali Haidar
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Stanley Ibeh
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Zaynab Shakkour
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Mohammad Amine Reslan
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Judith Nwaiwu
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Yomna Adel Moqidem
- Biotechnology Program, School of Science and Engineering, The American University in Cairo, Cairo, Egypt
| | - Georgio Sader
- Faculty of Medicine, University of Balamand, Balamand, Lebanon
| | - Rachel G. Nickles
- Program for Neurotrauma, Neuroproteomics & Biomarkers Research, Departments of Emergency Medicine, University of Florida, Gainesville, FL 32611, USA
| | - Ismail Babale
- Department of Biomedical Engineering, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Aneese A. Jaffa
- Department of Biology, Faculty of Arts and Sciences, American University of Beirut, Beirut, Lebanon
| | - Mohamed Salama
- Institute of Global Health and Human Ecology (I-GHHE), The American University in Cairo, New Cairo 11835, Egypt
- Global Brain Health Institute (GBHI), Trinity College Dublin, Dublin, Ireland
| | - Abdullah Shaito
- Biomedical Research Center, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Firas Kobeissy
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Department of Biomedical Engineering, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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6
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Huang H, Toker N, Burr E, Okoro J, Moog M, Hearing C, Lagalwar S. Intercellular Propagation and Aggregate Seeding of Mutant Ataxin-1. J Mol Neurosci 2021; 72:708-718. [PMID: 34826062 PMCID: PMC8986690 DOI: 10.1007/s12031-021-01944-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/06/2021] [Indexed: 01/07/2023]
Abstract
Intercellular propagation of aggregated protein inclusions along actin-based tunneling nanotubes (TNTs) has been reported as a means of pathogenic spread in Alzheimer’s, Parkinson’s, and Huntington’s diseases. Propagation of oligomeric-structured polyglutamine-expanded ataxin-1 (Atxn1[154Q]) has been reported in the cerebellum of a Spinocerebellar ataxia type 1 (SCA1) knock-in mouse to correlate with disease propagation. In this study, we investigated whether a physiologically relevant polyglutamine-expanded ATXN1 protein (ATXN1[82Q]) could propagate intercellularly. Using a cerebellar-derived live cell model, we observed ATXN1 aggregates form in the nucleus, subsequently form in the cytoplasm, and finally, propagate to neighboring cells along actin-based intercellular connections. Additionally, we observed the facilitation of aggregate-resistant proteins into aggregates given the presence of aggregation-prone proteins within cells. Taken together, our results support a pathogenic role of intercellular propagation of polyglutamine-expanded ATXN1 inclusions.
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Affiliation(s)
- Haoyang Huang
- Neuroscience Program, Skidmore College, Saratoga Springs, NY, USA
| | - Nicholas Toker
- Neuroscience Program, Skidmore College, Saratoga Springs, NY, USA
| | - Eliza Burr
- Neuroscience Program, Skidmore College, Saratoga Springs, NY, USA
| | - Jeff Okoro
- Neuroscience Program, Skidmore College, Saratoga Springs, NY, USA
| | - Maia Moog
- Neuroscience Program, Skidmore College, Saratoga Springs, NY, USA
| | - Casey Hearing
- Neuroscience Program, Skidmore College, Saratoga Springs, NY, USA
| | - Sarita Lagalwar
- Neuroscience Program, Skidmore College, Saratoga Springs, NY, USA.
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7
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A New Take on Prion Protein Dynamics in Cellular Trafficking. Int J Mol Sci 2020; 21:ijms21207763. [PMID: 33092231 PMCID: PMC7589859 DOI: 10.3390/ijms21207763] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/14/2020] [Accepted: 10/14/2020] [Indexed: 12/12/2022] Open
Abstract
The mobility of cellular prion protein (PrPC) in specific cell membrane domains and among distinct cell compartments dictates its molecular interactions and directs its cell function. PrPC works in concert with several partners to organize signaling platforms implicated in various cellular processes. The scaffold property of PrPC is able to gather a molecular repertoire to create heterogeneous membrane domains that favor endocytic events. Dynamic trafficking of PrPC through multiple pathways, in a well-orchestrated mechanism of intra and extracellular vesicular transport, defines its functional plasticity, and also assists the conversion and spreading of its infectious isoform associated with neurodegenerative diseases. In this review, we highlight how PrPC traffics across intra- and extracellular compartments and the consequences of this dynamic transport in governing cell functions and contributing to prion disease pathogenesis.
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8
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Del Rio JA, Ferrer I. Potential of Microfluidics and Lab-on-Chip Platforms to Improve Understanding of " prion-like" Protein Assembly and Behavior. Front Bioeng Biotechnol 2020; 8:570692. [PMID: 33015021 PMCID: PMC7506036 DOI: 10.3389/fbioe.2020.570692] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/18/2020] [Indexed: 12/14/2022] Open
Abstract
Human aging is accompanied by a relevant increase in age-associated chronic pathologies, including neurodegenerative and metabolic diseases. The appearance and evolution of numerous neurodegenerative diseases is paralleled by the appearance of intracellular and extracellular accumulation of misfolded proteins in affected brains. In addition, recent evidence suggests that most of these amyloid proteins can behave and propagate among neural cells similarly to infective prions. In order to improve understanding of the seeding and spreading processes of these "prion-like" amyloids, microfluidics and 3D lab-on-chip approaches have been developed as highly valuable tools. These techniques allow us to monitor changes in cellular and molecular processes responsible for amyloid seeding and cell spreading and their parallel effects in neural physiology. Their compatibility with new optical and biochemical techniques and their relative availability have increased interest in them and in their use in numerous laboratories. In addition, recent advances in stem cell research in combination with microfluidic platforms have opened new humanized in vitro models for myriad neurodegenerative diseases affecting different cellular targets of the vascular, muscular, and nervous systems, and glial cells. These new platforms help reduce the use of animal experimentation. They are more reproducible and represent a potential alternative to classical approaches to understanding neurodegeneration. In this review, we summarize recent progress in neurobiological research in "prion-like" protein using microfluidic and 3D lab-on-chip approaches. These approaches are driven by various fields, including chemistry, biochemistry, and cell biology, and they serve to facilitate the development of more precise human brain models for basic mechanistic studies of cell-to-cell interactions and drug discovery.
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Affiliation(s)
- Jose A Del Rio
- Molecular and Cellular Neurobiotechnology, Institute for Bioengineering of Catalonia, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Center for Networked Biomedical Research on Neurodegenerative Diseases (Ciberned), Barcelona, Spain.,Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - Isidre Ferrer
- Center for Networked Biomedical Research on Neurodegenerative Diseases (Ciberned), Barcelona, Spain.,Institute of Neuroscience, University of Barcelona, Barcelona, Spain.,Department of Pathology and Experimental Therapeutics, University of Barcelona, Barcelona, Spain.,Bellvitge University Hospital, Hospitalet de Llobregat, Barcelona, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat, Barcelona, Spain
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9
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Hara H, Sakaguchi S. N-Terminal Regions of Prion Protein: Functions and Roles in Prion Diseases. Int J Mol Sci 2020; 21:ijms21176233. [PMID: 32872280 PMCID: PMC7504422 DOI: 10.3390/ijms21176233] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 01/30/2023] Open
Abstract
The normal cellular isoform of prion protein, designated PrPC, is constitutively converted to the abnormally folded, amyloidogenic isoform, PrPSc, in prion diseases, which include Creutzfeldt-Jakob disease in humans and scrapie and bovine spongiform encephalopathy in animals. PrPC is a membrane glycoprotein consisting of the non-structural N-terminal domain and the globular C-terminal domain. During conversion of PrPC to PrPSc, its 2/3 C-terminal region undergoes marked structural changes, forming a protease-resistant structure. In contrast, the N-terminal region remains protease-sensitive in PrPSc. Reverse genetic studies using reconstituted PrPC-knockout mice with various mutant PrP molecules have revealed that the N-terminal domain has an important role in the normal function of PrPC and the conversion of PrPC to PrPSc. The N-terminal domain includes various characteristic regions, such as the positively charged residue-rich polybasic region, the octapeptide repeat (OR) region consisting of five repeats of an octapeptide sequence, and the post-OR region with another positively charged residue-rich polybasic region followed by a stretch of hydrophobic residues. We discuss the normal functions of PrPC, the conversion of PrPC to PrPSc, and the neurotoxicity of PrPSc by focusing on the roles of the N-terminal regions in these topics.
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10
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Banwarth-Kuhn M, Sindi S. How and why to build a mathematical model: A case study using prion aggregation. J Biol Chem 2020; 295:5022-5035. [PMID: 32005659 PMCID: PMC7152750 DOI: 10.1074/jbc.rev119.009851] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Biological systems are inherently complex, and the increasing level of detail with which we are able to experimentally probe such systems continually reveals new complexity. Fortunately, mathematical models are uniquely positioned to provide a tool suitable for rigorous analysis, hypothesis generation, and connecting results from isolated in vitro experiments with results from in vivo and whole-organism studies. However, developing useful mathematical models is challenging because of the often different domains of knowledge required in both math and biology. In this work, we endeavor to provide a useful guide for researchers interested in incorporating mathematical modeling into their scientific process. We advocate for the use of conceptual diagrams as a starting place to anchor researchers from both domains. These diagrams are useful for simplifying the biological process in question and distinguishing the essential components. Not only do they serve as the basis for developing a variety of mathematical models, but they ensure that any mathematical formulation of the biological system is led primarily by scientific questions. We provide a specific example of this process from our own work in studying prion aggregation to show the power of mathematical models to synergistically interact with experiments and push forward biological understanding. Choosing the most suitable model also depends on many different factors, and we consider how to make these choices based on different scales of biological organization and available data. We close by discussing the many opportunities that abound for both experimentalists and modelers to take advantage of collaborative work in this field.
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Affiliation(s)
- Mikahl Banwarth-Kuhn
- Department of Applied Mathematics, School of Natural Sciences, University of California, Merced, California 95343
| | - Suzanne Sindi
- Department of Applied Mathematics, School of Natural Sciences, University of California, Merced, California 95343
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11
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Mathews PM, Levy E. Exosome Production Is Key to Neuronal Endosomal Pathway Integrity in Neurodegenerative Diseases. Front Neurosci 2019; 13:1347. [PMID: 31911768 PMCID: PMC6920185 DOI: 10.3389/fnins.2019.01347] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/29/2019] [Indexed: 12/28/2022] Open
Abstract
Dysfunction of the endosomal–lysosomal system is a prominent pathogenic factor in Alzheimer’s disease (AD) and other neurodevelopmental and neurodegenerative disorders. We and others have extensively characterized the neuronal endosomal pathway pathology that results from either triplication of the amyloid-β precursor protein (APP) gene in Down syndrome (DS) or from expression of the apolipoprotein E ε4 allele (APOE4), the greatest genetic risk factor for late-onset AD. More recently brain exosomes, extracellular vesicles that are generated within and released from endosomal compartments, have been shown to be altered in DS and by APOE4 expression. In this review, we discuss the emerging data arguing for an interdependence between exosome production and endosomal pathway integrity in the brain. In vitro and in vivo studies indicate that altered trafficking through the endosomal pathway or compromised cargo turnover within lysosomes can affect the production, secretion, and content of exosomes. Conversely, exosome biogenesis can affect the endosomal–lysosomal system. Indeed, we propose that efficient exosome release helps to modulate flux through the neuronal endosomal pathway by decompressing potential “traffic jams.” Exosome secretion may have the added benefit of unburdening the neuron’s lysosomal system by delivering endosomal–lysosomal material into the extracellular space, where other cell types may contribute to the degradation of neuronal debris. Thus, maintaining robust neuronal exosome production may prevent or mitigate endosomal and lysosomal abnormalities linked to aging and neurodegenerative diseases. While the current evidence suggests that the exosomal system in the brain can be modulated both by membrane lipid composition and the expression of key proteins that contribute to the formation and secretion of exosomes, how exosomal pathway-regulatory elements sense and respond to perturbations in the endosomal pathway is not well understood. Based upon findings from the extensively studied DS and APOE4 models, we propose that enhanced neuronal exosome secretion can be a protective response, reducing pathological disruption of the endosomal–lysosomal system in disease-vulnerable neurons. Developing therapeutic approaches that help to maintain or enhance neuronal exosome biogenesis and release may be beneficial in a range of disorders of the central nervous system.
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Affiliation(s)
- Paul M Mathews
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, United States.,Department of Psychiatry, New York University Langone Health, New York, NY, United States.,NYU Neuroscience Institute, New York University Langone Health, New York, NY, United States
| | - Efrat Levy
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, United States.,Department of Psychiatry, New York University Langone Health, New York, NY, United States.,NYU Neuroscience Institute, New York University Langone Health, New York, NY, United States.,Department of Biochemistry and Molecular Pharmacology, New York University Langone Health, New York, NY, United States
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12
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Coudert L, Nonaka T, Bernard E, Hasegawa M, Schaeffer L, Leblanc P. Phosphorylated and aggregated TDP-43 with seeding properties are induced upon mutant Huntingtin (mHtt) polyglutamine expression in human cellular models. Cell Mol Life Sci 2019; 76:2615-2632. [PMID: 30863908 PMCID: PMC11105362 DOI: 10.1007/s00018-019-03059-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 02/06/2019] [Accepted: 03/01/2019] [Indexed: 12/14/2022]
Abstract
The Tar DNA-Binding Protein 43 (TDP-43) and its phosphorylated isoform (pTDP-43) are the major components associated with ubiquitin positive/Tau-negative inclusions found in neurons and glial cells of patients suffering of amyotrophic lateral sclerosis (ALS) or frontotemporal lobar degeneration-TDP-43 (FTLD-TDP). Many studies have revealed that TDP-43 is also in the protein inclusions associated with neurodegenerative conditions other than ALS and FTLD-TDP, thus suggesting that this protein may be involved in the pathogenesis of a variety of neurological disorders. In brains of Huntington-affected patients, pTDP-43 aggregates were shown to co-localize with mutant Huntingtin (mHtt) inclusions. Here, we show that expression of mHtt carrying 80-97 polyglutamines repeats in human cell cultures induces the aggregation and the phosphorylation of endogenous TDP-43, whereas non-pathological Htt with 25 polyglutamines repeats has no effect. Mutant Htt aggregation precedes accumulation of pTDP-43 and pTDP-43 co-localizes with mHtt inclusions reminding what it was previously described in brains of Huntington-affected patients. Detergent-insoluble fractions from cells expressing mHtt and containing mHtt-pTDP-43 co-aggregates can function as seeds for further TDP-43 aggregation in human cell culture. The human cellular prion protein PrPC was previously identified as a negative modulator of mHtt aggregation; here, we show that PrPC-mediated reduction of mHtt aggregation is tightly correlated with a decrease of TDP-43 aggregation and phosphorylation, thus confirming the close relationships between TDP-43 and mHtt.
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Affiliation(s)
- Laurent Coudert
- Institut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon I, 8 Avenue Rockefeller, 69373, Lyon Cedex 08, France
| | - Takashi Nonaka
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan
| | - Emilien Bernard
- Hospices Civils de Lyon, Hôpital Neurologique Pierre-Wertheimer, Service de Neurologie C et Centre SLA de Lyon, Bron, France
- Université de Lyon, Faculté de Médecine Lyon Sud Charles Mérieux, Lyon, France
| | - Masato Hasegawa
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan
| | - Laurent Schaeffer
- Institut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon I, 8 Avenue Rockefeller, 69373, Lyon Cedex 08, France
| | - Pascal Leblanc
- Institut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon I, 8 Avenue Rockefeller, 69373, Lyon Cedex 08, France.
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13
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You Y, Ikezu T. Emerging roles of extracellular vesicles in neurodegenerative disorders. Neurobiol Dis 2019; 130:104512. [PMID: 31229685 DOI: 10.1016/j.nbd.2019.104512] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 06/17/2019] [Indexed: 12/11/2022] Open
Abstract
Extracellular vesicles (EVs) are heterogeneous cell-derived membranous vesicles which carry a large diversity of molecules such as proteins and RNA species. They are now considered to be a general mode of intercellular communication by direct transfer of biomolecules. Emerging evidence demonstrates that EVs are involved in multiple pathological processes of brain diseases including neurodegenerative disorders. In this review, we investigate the current knowledge about EV biology. We also provide an overview of the roles of EVs in related brain diseases, particularly in neurodegenerative disorders. Finally, we discuss their potential applications as novel biomarkers as well as the developments of EV-based therapies.
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Affiliation(s)
- Yang You
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Tsuneya Ikezu
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA; Neurology, Boston University School of Medicine, Boston, MA, USA.
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14
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Feng T, Zhang P, Sun Y, Wang Y, Tong J, Dai H, Hua Z. High throughput sequencing identifies breast cancer-secreted exosomal LncRNAs initiating pulmonary pre-metastatic niche formation. Gene 2019; 710:258-264. [PMID: 31176731 DOI: 10.1016/j.gene.2019.06.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 06/03/2019] [Accepted: 06/05/2019] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Increasing evidence indicated that cancer-secreted exosomes played an important role in tumor metastasis. However, the function of exosomes in breast cancer pulmonary metastasis remains unknown. The aim of the study was to investigate the role of exosome-derived from breast cancer-secreted long non-coding RNAs (LncRNAs) on pre-metastatic niche formation in pulmonary metastasis. METHODS Exosomes-derived from breast cancer were separated by ultracentrifugation. The high-throughput sequencing, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were used to detect and evaluate the differential expression of LncRNAs in lung fibroblasts with exosomes treated. And quantitative real-time polymerase chain reaction (qRT-PCR) was performed to verify candidate LncRNAs expression. RESULTS We found that exosomes-derived from breast cancer induced lung fibroblasts proliferation and migration. In addition, a large number of LncRNAs expression abnormalities were involved in the breast cancer lung metastasis microenvironment. CONCLUSION Our findings suggested that exosomal LncRNAs facilitated tumor pre-metastatic niche formation and represented a novel mechanistic insight into the molecular mechanism of cancer metastasis microenvironment.
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Affiliation(s)
- Tongbao Feng
- The State Key Laboratory of Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing, PR China; Department of Clinical Laboratory, the Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University, Changzhou, PR China; Department of General Surgery, the Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University, Changzhou, PR China
| | - Ping Zhang
- Department of Clinical Laboratory, the Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University, Changzhou, PR China
| | - Yingxin Sun
- Department of Clinical Laboratory, the Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University, Changzhou, PR China
| | - Yan Wang
- Department of Clinical Laboratory, the Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University, Changzhou, PR China
| | - Jichun Tong
- Department of Cardiac Surgery, the Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University, Changzhou, PR China
| | - Hong Dai
- Department of General Surgery, the Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University, Changzhou, PR China.
| | - Zichun Hua
- The State Key Laboratory of Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing, PR China; Changzhou High-Tech Research Institute of Nanjing University and Jiangsu Target Pharma Laboratories Inc., Changzhou, PR China.
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15
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Abdelaziz DH, Abdulrahman BA, Gilch S, Schatzl HM. Autophagy pathways in the treatment of prion diseases. Curr Opin Pharmacol 2019; 44:46-52. [PMID: 31096117 DOI: 10.1016/j.coph.2019.04.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/12/2019] [Accepted: 04/15/2019] [Indexed: 01/04/2023]
Abstract
Prions use cellular machineries for autocatalytic propagation by conformational conversion of the cellular prion protein into the pathological isoform PrPSc. Autophagy is a basic cellular degradation and recycling machinery that delivers cargo to lysosomes. Increase of autophagic flux in cells results in enhanced delivery of PrPSc in late endosomes to lysosomal degradation, providing a therapeutic target for prion diseases. Application of chemical enhancers of autophagy to cell or mouse models of prion infection provided a solid experimental proof-of-concept for this anti-prion strategy. In addition, increasing autophagy also reduces exosomal release of prions and transfer of prion infectivity between cells. Taken together, pharmacological induction of autophagy is a promising target for containing prion diseases, and ideal candidate for future combination therapies.
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Affiliation(s)
- Dalia H Abdelaziz
- Calgary Prion Research Unit, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Department of Comparative Biology & Experimental Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Basant A Abdulrahman
- Calgary Prion Research Unit, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Department of Comparative Biology & Experimental Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sabine Gilch
- Calgary Prion Research Unit, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Department of Ecosystem and Public Health, University of Calgary, Calgary, Alberta, Canada
| | - Hermann M Schatzl
- Calgary Prion Research Unit, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Department of Comparative Biology & Experimental Medicine, University of Calgary, Calgary, Alberta, Canada.
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16
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Bistaffa E, Rossi M, De Luca CMG, Cazzaniga F, Carletta O, Campagnani I, Tagliavini F, Legname G, Giaccone G, Moda F. Prion Efficiently Replicates in α-Synuclein Knockout Mice. Mol Neurobiol 2019; 56:7448-7457. [PMID: 31041657 DOI: 10.1007/s12035-019-1602-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/09/2019] [Indexed: 10/26/2022]
Abstract
Prion diseases are a group of neurodegenerative disorders associated with the conformational conversion of the cellular prion protein (PrPC) into an abnormal misfolded form named PrPSc. Other than accumulating in the brain, PrPSc can bind PrPC and force it to change conformation to PrPSc. The exact mechanism which underlies the process of PrPC/PrPSc conversion still needs to be defined and many molecules or cofactors might be involved. Several studies have documented an important role of PrPC to act as receptor for abnormally folded forms of α-synuclein which are responsible of a group of diseases known as synucleinopathies. The presence of PrPC was required to promote efficient internalization and spreading of abnormal α-synuclein between cells. In this work, we have assessed whether α-synuclein exerts any role in PrPSc conversion and propagation either in vitro or in vivo. Indeed, understanding the mechanism of PrPC/PrPSc conversion and the identification of cofactors involved in this process is crucial for developing new therapeutic strategies. Our results showed that PrPSc was able to efficiently propagate in the brain of animals even in the absence of α-synuclein thus suggesting that this protein did not act as key modulator of prion propagation. Thus, α-synuclein might take part in this process but is not specifically required for sustaining prion conversion and propagation.
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Affiliation(s)
- Edoardo Bistaffa
- Unit of Neuropathology and Neurology 5, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Martina Rossi
- Department of Neuroscience, Laboratory of Prion Biology, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Chiara Maria Giulia De Luca
- Unit of Neuropathology and Neurology 5, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.,Department of Neuroscience, Laboratory of Prion Biology, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Federico Cazzaniga
- Unit of Neuropathology and Neurology 5, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Olga Carletta
- Unit of Neuropathology and Neurology 5, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Ilaria Campagnani
- Unit of Neuropathology and Neurology 5, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Fabrizio Tagliavini
- Unit of Neuropathology and Neurology 5, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Giuseppe Legname
- Department of Neuroscience, Laboratory of Prion Biology, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Giorgio Giaccone
- Unit of Neuropathology and Neurology 5, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Fabio Moda
- Unit of Neuropathology and Neurology 5, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
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17
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Vorberg IM. All the Same? The Secret Life of Prion Strains within Their Target Cells. Viruses 2019; 11:v11040334. [PMID: 30970585 DOI: 10.3390/v11040334] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/02/2019] [Accepted: 04/05/2019] [Indexed: 01/23/2023] Open
Abstract
Prions are infectious β-sheet-rich protein aggregates composed of misfolded prion protein (PrPSc) that do not possess coding nucleic acid. Prions replicate by recruiting and converting normal cellular PrPC into infectious isoforms. In the same host species, prion strains target distinct brain regions and cause different disease phenotypes. Prion strains are associated with biophysically distinct PrPSc conformers, suggesting that strain properties are enciphered within alternative PrPSc quaternary structures. So far it is unknown how prion strains target specific cells and initiate productive infections. Deeper mechanistic insight into the prion life cycle came from cell lines permissive to a range of different prion strains. Still, it is unknown why certain cell lines are refractory to infection by one strain but permissive to another. While pharmacologic and genetic manipulations revealed subcellular compartments involved in prion replication, little is known about strain-specific requirements for endocytic trafficking pathways. This review summarizes our knowledge on how prions replicate within their target cells and on strain-specific differences in prion cell biology.
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Affiliation(s)
- Ina M Vorberg
- German Center for Neurodegenerative Diseases (DZNE e.V.), Sigmund-Freud-Strasse 27, 53127 Bonn, Germany.
- Rheinische Friedrich-Wilhelms-Universität Bonn, 53127 Bonn, Germany.
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18
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Szepesi Z, Manouchehrian O, Bachiller S, Deierborg T. Bidirectional Microglia-Neuron Communication in Health and Disease. Front Cell Neurosci 2018; 12:323. [PMID: 30319362 PMCID: PMC6170615 DOI: 10.3389/fncel.2018.00323] [Citation(s) in RCA: 279] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/06/2018] [Indexed: 12/12/2022] Open
Abstract
Microglia are ramified cells that exhibit highly motile processes, which continuously survey the brain parenchyma and react to any insult to the CNS homeostasis. Although microglia have long been recognized as a crucial player in generating and maintaining inflammatory responses in the CNS, now it has become clear, that their function are much more diverse, particularly in the healthy brain. The innate immune response and phagocytosis represent only a little segment of microglia functional repertoire that also includes maintenance of biochemical homeostasis, neuronal circuit maturation during development and experience-dependent remodeling of neuronal circuits in the adult brain. Being equipped by numerous receptors and cell surface molecules microglia can perform bidirectional interactions with other cell types in the CNS. There is accumulating evidence showing that neurons inform microglia about their status and thus are capable of controlling microglial activation and motility while microglia also modulate neuronal activities. This review addresses the topic: how microglia communicate with other cell types in the brain, including fractalkine signaling, secreted soluble factors and extracellular vesicles. We summarize the current state of knowledge of physiological role and function of microglia during brain development and in the mature brain and further highlight microglial contribution to brain pathologies such as Alzheimer’s and Parkinson’s disease, brain ischemia, traumatic brain injury, brain tumor as well as neuropsychiatric diseases (depression, bipolar disorder, and schizophrenia).
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Affiliation(s)
- Zsuzsanna Szepesi
- Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Oscar Manouchehrian
- Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Sara Bachiller
- Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Tomas Deierborg
- Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, Lund University, Lund, Sweden
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19
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Tang BL. Unconventional Secretion and Intercellular Transfer of Mutant Huntingtin. Cells 2018; 7:cells7060059. [PMID: 29904030 PMCID: PMC6025013 DOI: 10.3390/cells7060059] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 06/08/2018] [Accepted: 06/12/2018] [Indexed: 01/17/2023] Open
Abstract
The mechanism of intercellular transmission of pathological agents in neurodegenerative diseases has received much recent attention. Huntington’s disease (HD) is caused by a monogenic mutation in the gene encoding Huntingtin (HTT). Mutant HTT (mHTT) harbors a CAG repeat extension which encodes an abnormally long polyglutamine (polyQ) repeat at HTT’s N-terminus. Neuronal pathology in HD is largely due to the toxic gain-of-function by mHTT and its proteolytic products, which forms both nuclear and cytoplasmic aggregates that perturb nuclear gene transcription, RNA splicing and transport as well cellular membrane dynamics. The neuropathological effects of mHTT have been conventionally thought to be cell-autonomous in nature. Recent findings have, however, indicated that mHTT could be secreted by neurons, or transmitted from one neuronal cell to another via different modes of unconventional secretion, as well as via tunneling nanotubes (TNTs). These modes of transmission allow the intercellular spread of mHTT and its aggregates, thus plausibly promoting neuropathology within proximal neuronal populations and between neurons that are connected within neural circuits. Here, the various possible modes for mHTT’s neuronal cell exit and intercellular transmission are discussed.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, 117597 Singapore, Singapore.
- NUS Graduate School for Integrative Sciences and Engineering, 117456 Singapore, Singapore.
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