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Schmitt-Ulms G, Mehrabian M, Williams D, Ehsani S. The IDIP framework for assessing protein function and its application to the prion protein. Biol Rev Camb Philos Soc 2021; 96:1907-1932. [PMID: 33960099 DOI: 10.1111/brv.12731] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 01/06/2023]
Abstract
The quest to determine the function of a protein can represent a profound challenge. Although this task is the mandate of countless research groups, a general framework for how it can be approached is conspicuously lacking. Moreover, even expectations for when the function of a protein can be considered to be 'known' are not well defined. In this review, we begin by introducing concepts pertinent to the challenge of protein function assignments. We then propose a framework for inferring a protein's function from four data categories: 'inheritance', 'distribution', 'interactions' and 'phenotypes' (IDIP). We document that the functions of proteins emerge at the intersection of inferences drawn from these data categories and emphasise the benefit of considering them in an evolutionary context. We then apply this approach to the cellular prion protein (PrPC ), well known for its central role in prion diseases, whose function continues to be considered elusive by many investigators. We document that available data converge on the conclusion that the function of the prion protein is to control a critical post-translational modification of the neural cell adhesion molecule in the context of epithelial-to-mesenchymal transition and related plasticity programmes. Finally, we argue that this proposed function of PrPC has already passed the test of time and is concordant with the IDIP framework in a way that other functions considered for this protein fail to achieve. We anticipate that the IDIP framework and the concepts analysed herein will aid the investigation of other proteins whose primary functional assignments have thus far been intractable.
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Affiliation(s)
- Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, M5T 0S8, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | | | - Declan Williams
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, M5T 0S8, Canada
| | - Sepehr Ehsani
- Theoretical and Philosophical Biology, Department of Philosophy, University College London, Bloomsbury, London, WC1E 6BT, U.K.,Ronin Institute for Independent Scholarship, Montclair, NJ, 07043, U.S.A
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2
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Prado MB, Melo Escobar MI, Alves RN, Coelho BP, Fernandes CFDL, Boccacino JM, Iglesia RP, Lopes MH. Prion Protein at the Leading Edge: Its Role in Cell Motility. Int J Mol Sci 2020; 21:E6677. [PMID: 32932634 PMCID: PMC7555277 DOI: 10.3390/ijms21186677] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 02/06/2023] Open
Abstract
Cell motility is a central process involved in fundamental biological phenomena during embryonic development, wound healing, immune surveillance, and cancer spreading. Cell movement is complex and dynamic and requires the coordinated activity of cytoskeletal, membrane, adhesion and extracellular proteins. Cellular prion protein (PrPC) has been implicated in distinct aspects of cell motility, including axonal growth, transendothelial migration, epithelial-mesenchymal transition, formation of lamellipodia, and tumor migration and invasion. The preferential location of PrPC on cell membrane favors its function as a pivotal molecule in cell motile phenotype, being able to serve as a scaffold protein for extracellular matrix proteins, cell surface receptors, and cytoskeletal multiprotein complexes to modulate their activities in cellular movement. Evidence points to PrPC mediating interactions of multiple key elements of cell motility at the intra- and extracellular levels, such as integrins and matrix proteins, also regulating cell adhesion molecule stability and cell adhesion cytoskeleton dynamics. Understanding the molecular mechanisms that govern cell motility is critical for tissue homeostasis, since uncontrolled cell movement results in pathological conditions such as developmental diseases and tumor dissemination. In this review, we discuss the relevant contribution of PrPC in several aspects of cell motility, unveiling new insights into both PrPC function and mechanism in a multifaceted manner either in physiological or pathological contexts.
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Affiliation(s)
| | | | | | | | | | | | | | - Marilene Hohmuth Lopes
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil; (M.B.P.); (M.I.M.E.); (R.N.A.); (B.P.C.); (C.F.d.L.F.); (J.M.B.); (R.P.I.)
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Lipid Reshaping and Lipophagy Are Induced in a Modeled Ischemia-Reperfusion Injury of Blood Brain Barrier. Int J Mol Sci 2019; 20:ijms20153752. [PMID: 31370282 PMCID: PMC6696511 DOI: 10.3390/ijms20153752] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/26/2019] [Accepted: 07/29/2019] [Indexed: 02/07/2023] Open
Abstract
Ischemic-reperfusion (I/R) injury induced a remodeling of protein and lipid homeostasis, under oxidative stress and inflammatory status. Starvation occurring during I/R is a condition leading to autophagy activation, which allows abnormal material clearance or amino acid, or both, and fatty acid (FA) recycling essential for survival. This study investigated the lipid reshaping, peroxidation, and related-signaling pathways, in rat brain endothelial cells (RBE4) subjected to 3 h of oxygen and glucose deprivation (OGD) and restoration of standard condition (I/R in vitro model). Lipids and proteins were analyzed after 1 or 24 h of oxygen and nutrient restoration. Together with the oxidative stress and inflammatory status, I/R injury induced a reshaping of neutral lipids and biogenesis of lipid droplets (LD) with excessive lipid storage. The increase of LC3-II/LC3-I ratio, an autophagy marker, and LC3 co-localization with LD suggest the activation of lipophagy machinery to counteract the cell engulfment. Lipophagy leads to cholesterol ester (CE) hydrolysis, increasing free cholesterol (FC) secretion, which occurred by specific transporters or unconventional exocytosis pathways, or both. Here, we propose that an unconventional spreading of FC and other lipid metabolites may influence the neurovascular unit (NVU) cells, contributing to Blood brain barrier (BBB) alteration or adaptation, or both, to the cumulative effects of several transient ischemia.
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Megra BW, Eugenin EA, Berman JW. Inflammatory mediators reduce surface PrP c on human BMVEC resulting in decreased barrier integrity. J Transl Med 2018; 98:1347-1359. [PMID: 29959417 PMCID: PMC6163073 DOI: 10.1038/s41374-018-0090-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 05/03/2018] [Accepted: 05/05/2018] [Indexed: 12/18/2022] Open
Abstract
The cellular prion protein (PrPc) is a surface adhesion molecule expressed at junctions of various cell types including brain microvascular endothelial cells (BMVEC) that are important components of the blood-brain barrier (BBB). PrPc is involved in several physiological processes including regulation of epithelial cell barrier function and monocyte migration across BMVEC. BBB dysfunction and disruption are significant events in central nervous system (CNS) inflammatory processes including HIV neuropathogenesis. Tumor necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF) are two inflammatory factors that have been implicated in the processes that affect BBB integrity. To examine the effect of inflammation on PrPc expression in BMVEC, we used these mediators and found that TNF-α and VEGF decrease surface PrPc on primary human BMVEC. We also showed that these factors decrease total PrPc protein as well as mRNA, indicating that they regulate expression of this protein by de novo synthesis. To determine the effect of PrPc loss from the surface of BMVEC on barrier integrity, we used small hairpin RNAs to knockdown PrPc. We found that the absence of PrPc from BMVEC causes increased permeability as determined by a fluorescein isothiocyanate (FITC)-dextran permeability assay. This suggests that cell surface PrPc is essential for endothelial monolayer integrity. To determine the mechanism by which PrPc downregulation leads to increased permeability of an endothelial monolayer, we examined changes in expression and localization of tight junction proteins, occludin and claudin-5, and found that decreased PrPc leads to decreased total and membrane-associated occludin and claudin-5. We propose that an additional mechanism by which inflammatory factors affect endothelial monolayer permeability is by decreasing cell-associated PrPc. This increase in permeability may have subsequent consequences that lead to CNS damage.
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Affiliation(s)
- Bezawit W. Megra
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Eliseo A. Eugenin
- Public Health Research Institute (PHRI), Newark, NJ 07103,Department of Microbiology and Molecular Genetics, Rutgers New Jersey Medical School, Rutgers The State University of New Jersey, Newark, NJ 07103
| | - Joan W. Berman
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461,Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461
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Li N, Hu P, Xu T, Chen H, Chen X, Hu J, Yang X, Shi L, Luo JH, Xu J. iTRAQ-based Proteomic Analysis of APPSw,Ind Mice Provides Insights into the Early Changes in Alzheimer's Disease. Curr Alzheimer Res 2018; 14:1109-1122. [PMID: 28730955 PMCID: PMC5676024 DOI: 10.2174/1567205014666170719165745] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/13/2017] [Accepted: 06/29/2017] [Indexed: 01/17/2023]
Abstract
BACKGROUND Several proteins have been identified as potential diagnostic biomarkers in imaging, genetic, or proteomic studies in Alzheimer disease (AD) patients and mouse models. However, biomarkers for presymptom diagnosis of AD are still under investigation, as are the presymptom molecular changes in AD pathogenesis. OBJECTIVE In this study, we aim to analyzed the early proteomic changes in APPSw,Ind mice and to conduct further functional studies on interesting proteins. METHODS We used the isobaric tags for relative and absolute quantitation (iTRAQ) approach combined with mass spectrometry to examine the early proteomic changes in hippocampi of APPSw,Ind mice. Quantitative reverse transcription polymerase chain reaction (RT-PCR) and immuno-blotting were performed for further validation. Finally, the functions of interesting proteins β-spectrin and Rab3a in APP trafficking and processing were tested by shRNA knockdown, in N2A cells stably expressing β-amyloid precursor protein (APP). RESULTS The iTRAQ and RT-PCR results revealed the detailed molecular changes in oxidative stress, myelination, astrocyte activation, mTOR signaling and Rab3-dependent APP trafficking in the early stage of AD progression. Knock down of β -spectrin and Rab3a finally led to increased APP fragment production, indicating key roles of β-spectrin and Rab3a in regulating APP processing. CONCLUSION Our study provides the first insights into the proteomic changes that occur in the hippocampus in the early stages of the AD mouse model. In addition to improving the understanding of molecular alterations and functional cascades involved in early AD pathogenesis, our findings raise the possibility of developing potential biomarkers and therapeutic targets for early AD.
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Affiliation(s)
- Nan Li
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Pinghong Hu
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Tiantian Xu
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Huan Chen
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Xiaoying Chen
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Jianwen Hu
- Shanghai Applied Protein Technology Co., Ltd., Shanghai. China
| | - Xifei Yang
- Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen. China
| | - Lei Shi
- Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen. China
| | - Jian-Hong Luo
- Center of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058. China
| | - Junyu Xu
- Center of Neuroscience, Zhejiang University, 866 Yuhangtang Road, Hangzhou. China
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Mehrabian M, Hildebrandt H, Schmitt-Ulms G. NCAM1 Polysialylation: The Prion Protein's Elusive Reason for Being? ASN Neuro 2016; 8:8/6/1759091416679074. [PMID: 27879349 PMCID: PMC5122176 DOI: 10.1177/1759091416679074] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 09/08/2016] [Accepted: 10/02/2016] [Indexed: 01/06/2023] Open
Abstract
Much confusion surrounds the physiological function of the cellular prion protein (PrPC). It is, however, anticipated that knowledge of its function will shed light on its contribution to neurodegenerative diseases and suggest ways to interfere with the cellular toxicity central to them. Consequently, efforts to elucidate its function have been all but exhaustive. Building on earlier work that uncovered the evolutionary descent of the prion founder gene from an ancestral ZIP zinc transporter, we recently investigated a possible role of PrPC in a morphogenetic program referred to as epithelial-to-mesenchymal transition (EMT). By capitalizing on PrPC knockout cell clones in a mammalian cell model of EMT and using a comparative proteomics discovery strategy, neural cell adhesion molecule-1 emerged as a protein whose upregulation during EMT was perturbed in PrPC knockout cells. Follow-up work led us to observe that PrPC regulates the polysialylation of the neural cell adhesion molecule NCAM1 in cells undergoing morphogenetic reprogramming. In addition to governing cellular migration, polysialylation modulates several other cellular plasticity programs PrPC has been phenotypically linked to. These include neurogenesis in the subventricular zone, controlled mossy fiber sprouting and trimming in the hippocampal formation, hematopoietic stem cell renewal, myelin repair and maintenance, integrity of the circadian rhythm, and glutamatergic signaling. This review revisits this body of literature and attempts to present it in light of this novel contextual framework. When approached in this manner, a coherent model of PrPC acting as a regulator of polysialylation during specific cell and tissue morphogenesis events comes into focus.
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Affiliation(s)
- Mohadeseh Mehrabian
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Herbert Hildebrandt
- Institute for Cellular Chemistry, Hannover Medical School, Hannover, Germany
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada .,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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7
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Brambillaa A, Lonati E, Milani C, Rizzo AM, Farina F, Botto L, Masserini M, Palestini P, Bulbarelli A. Ischemic conditions and ß-secretase activation: The impact of membrane cholesterol enrichment as triggering factor in rat brain endothelial cells. Int J Biochem Cell Biol 2016; 69:95-104. [PMID: 27022655 DOI: 10.1016/j.biocel.2015.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Among harmful conditions damaging the blood–brain barrier, cerebral stroke and reperfusion injuries were proposed as contributing factors to Alzheimer's disease etiology. Indeed it was reported that ischemic conditions promote β-amyloid peptide production in brain endothelial cells, although implicated mechanisms are yet not fully understood.Oxidative injury related to ischemia affects membrane-lipids profile by altering their biochemical properties and structural dynamics, which are also believed to play significant role in the amyloid precursor protein processing, suggesting a link between alterations in lipid membrane composition and β-amyloid peptide production enhancement.Using brain microvascular endothelial cells, here we demonstrate how oxygen and glucose deprivation followed by normal conditions restoration, mimicking ischemic environment, increases cell cholesterol amount (+20%), reduces membrane fluidity and results in strong activation (+40%) of β-secretase 1 enzymatic activity. Moreover, we observed an increase of amyloid precursor protein and β-secretase 1 protein levels with altered localization in non-discrete (Triton X-100 soluble) membrane domains, leading to an enhanced production of amyloid precursor protein β-carboxyl-terminal fragment. Therefore, lipid alterations induced by oxygen and glucose deprivation enhance β-secretase 1 activity, favor its proximity to amyloid precursor protein and may concur to increased amyloidogenic cleavage. The latter, represents a detrimental event that may contribute to β-amyloid homeostasis impairment in the brain and to Alzheimer's disease-related BBB dysfunctions.
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Dall'Ara P, Iulini B, Botto L, Filipe J, Martino PA, Pintore MD, Gazzuola P, Mazza M, Dagrada M, Ingravalle F, Casalone C, Palestini P, Poli G. Diets with different lipid contents do not modify the neuronal membrane lipid raft profile in a scrapie murine model. Life Sci 2016; 144:226-33. [PMID: 26655166 DOI: 10.1016/j.lfs.2015.12.008] [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: 04/17/2015] [Revised: 11/26/2015] [Accepted: 12/02/2015] [Indexed: 10/22/2022]
Abstract
UNLABELLED In Transmissible Spongiform Encephalopathies (TSEs), the localization of the prion protein in the neuronal membrane lipid rafts (LR) seems to play a role in sustaining the protein misfolding. Changes in membrane properties, due to altered lipid composition, affect their organization and interaction between lipids and protein therein, and consequently also membrane resident protein functionality; dietary polyunsaturated fatty acids (PUFAs), gangliosides and cholesterol seem to influence these processes. AIMS In this work, the influence of administration of different feed, able to change the composition of lipid membrane, on the clinical progression of prion disease was studied. MAIN METHODS The activity of three diets (hyperlipidic with 6% fats; hypolipidic with 0.1% fats; and purified with 4% fats) was tested in CD1 mouse model experimentally infected with RML scrapie strain. Presence and distribution of typical central nervous system (CNS) lesions and deposits of PrP(sc) were evaluated by histopathological analysis and immunohistochemistry. Analysis of lipids was performed in homogenate and insoluble brain fraction of the neuronal membrane rich in LR. KEY FINDINGS Results show that a diet with a different lipid level has not a significant role in the development of the scrapie disease. All infected mice fed with different diets died in the same time span. Histology, immunohistochemistry, and neuropathological analyses of the infected brains did not show significant differences between animals subjected to different diets. SIGNIFICANCE Independently of the diet, the infection induced a significant modification of the lipid composition in homogenates, and a less noticeable one in insoluble brain fraction.
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Affiliation(s)
- Paola Dall'Ara
- Department of Veterinary Science and Public Health, University of Milan, Milan, Italy.
| | - Barbara Iulini
- CEA, Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Turin, Italy
| | - Laura Botto
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Joel Filipe
- Department of Veterinary Science and Public Health, University of Milan, Milan, Italy
| | - Piera Anna Martino
- Department of Veterinary Science and Public Health, University of Milan, Milan, Italy
| | - Maria Domenica Pintore
- CEA, Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Turin, Italy
| | - Paola Gazzuola
- CEA, Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Turin, Italy
| | - Maria Mazza
- CEA, Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Turin, Italy
| | - Massimo Dagrada
- Department of Veterinary Science and Public Health, University of Milan, Milan, Italy
| | - Francesco Ingravalle
- CEA, Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Turin, Italy
| | - Cristina Casalone
- CEA, Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Turin, Italy
| | - Paola Palestini
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Giorgio Poli
- Department of Veterinary Science and Public Health, University of Milan, Milan, Italy
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Botto L, Cunati D, Coco S, Sesana S, Bulbarelli A, Biasini E, Colombo L, Negro A, Chiesa R, Masserini M, Palestini P. Role of lipid rafts and GM1 in the segregation and processing of prion protein. PLoS One 2014; 9:e98344. [PMID: 24859148 PMCID: PMC4032283 DOI: 10.1371/journal.pone.0098344] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 05/01/2014] [Indexed: 12/04/2022] Open
Abstract
The prion protein (PrPC) is highly expressed within the nervous system. Similar to other GPI-anchored proteins, PrPC is found in lipid rafts, membrane domains enriched in cholesterol and sphingolipids. PrPC raft association, together with raft lipid composition, appears essential for the conversion of PrPC into the scrapie isoform PrPSc, and the development of prion disease. Controversial findings were reported on the nature of PrPC-containing rafts, as well as on the distribution of PrPC between rafts and non-raft membranes. We investigated PrPC/ganglioside relationships and their influence on PrPC localization in a neuronal cellular model, cerebellar granule cells. Our findings argue that in these cells at least two PrPC conformations coexist: in lipid rafts PrPC is present in the native folding (α-helical), stabilized by chemico-physical condition, while it is mainly present in other membrane compartments in a PrPSc-like conformation. We verified, by means of antibody reactivity and circular dichroism spectroscopy, that changes in lipid raft-ganglioside content alters PrPC conformation and interaction with lipid bilayers, without modifying PrPC distribution or cleavage. Our data provide new insights into the cellular mechanism of prion conversion and suggest that GM1-prion protein interaction at the cell surface could play a significant role in the mechanism predisposing to pathology.
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Affiliation(s)
- Laura Botto
- Department of Health Science - Medical School, University of Milano-Bicocca, Monza, Italy
- * E-mail:
| | - Diana Cunati
- Department of Health Science - Medical School, University of Milano-Bicocca, Monza, Italy
| | - Silvia Coco
- Department of Health Science - Medical School, University of Milano-Bicocca, Monza, Italy
| | - Silvia Sesana
- Department of Health Science - Medical School, University of Milano-Bicocca, Monza, Italy
| | - Alessandra Bulbarelli
- Department of Health Science - Medical School, University of Milano-Bicocca, Monza, Italy
| | - Emiliano Biasini
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Laura Colombo
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Alessandro Negro
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Roberto Chiesa
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Massimo Masserini
- Department of Health Science - Medical School, University of Milano-Bicocca, Monza, Italy
| | - Paola Palestini
- Department of Health Science - Medical School, University of Milano-Bicocca, Monza, Italy
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10
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Campisi E, Cardone F, Graziano S, Galeno R, Pocchiari M. Role of proteomics in understanding prion infection. Expert Rev Proteomics 2013; 9:649-66. [PMID: 23256675 DOI: 10.1586/epr.12.58] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Transmissible spongiform encephalopathies or prion diseases are fatal neurodegenerative pathologies characterized by the autocatalytic misfolding and polymerization of a cellular glycoprotein (cellular prion protein [PrP(C)]) that accumulates in the CNS and leads to neurodegeneration. The detailed mechanics of PrP(C) conversion to its pathological isoform (PrP(TSE)) are unclear but one or more exogenous factors are likely involved in the process of PrP misfolding. In the last 20 years, proteomic investigations have identified several endogenous proteins that interact with PrP(C), PrP(TSE) or both, which are possibly involved in the prion pathogenetic process. However, current approaches have not yet produced convincing conclusions on the biological value of such PrP interactors. Future advancements in the comprehension of the molecular pathogenesis of prion diseases, in experimental techniques and in data analysis procedures, together with a boost in more productive international collaborations, are therefore needed to improve the understanding on the role of PrP interactors. Finally, the advancement of 'omics' techniques in prion diseases will contribute to the development of novel diagnostic tests and effective drugs.
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Affiliation(s)
- Edmondo Campisi
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
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Llorens F, Del Río JA. Unraveling the neuroprotective mechanisms of PrP (C) in excitotoxicity. Prion 2012; 6:245-51. [PMID: 22437735 DOI: 10.4161/pri.19639] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Knowledge of the natural roles of cellular prion protein (PrP (C) ) is essential to an understanding of the molecular basis of prion pathologies. This GPI-anchored protein has been described in synaptic contacts, and loss of its synaptic function in complex systems may contribute to the synaptic loss and neuronal degeneration observed in prionopathy. In addition, Prnp knockout mice show enhanced susceptibility to several excitotoxic insults, GABAA receptor-mediated fast inhibition was weakened, LTP was modified and cellular stress increased. Although little is known about how PrP (C) exerts its function at the synapse or the downstream events leading to PrP (C) -mediated neuroprotection against excitotoxic insults, PrP (C) has recently been reported to interact with two glutamate receptor subunits (NR2D and GluR6/7). In both cases the presence of PrP (C) blocks the neurotoxicity induced by NMDA and Kainate respectively. Furthermore, signals for seizure and neuronal cell death in response to Kainate in Prnp knockout mouse are associated with JNK3 activity, through enhancing the interaction of GluR6 with PSD-95. In combination with previous data, these results shed light on the molecular mechanisms behind the role of PrP (C) in excitotoxicity. Future experimental approaches are suggested and discussed.
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Affiliation(s)
- Franc Llorens
- Molecular and Cellular Neurobiotechnology Group, Institut de Bioenginyeria de Catalunya (IBEC), Parc Científic de Barcelona, Barcelona, Spain.
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