scholarly journals Do Bovine Lymphocytes Express a Peculiar Prion Protein?

2002 ◽  
Vol 9 (4) ◽  
pp. 245-252 ◽  
Author(s):  
France Mélot ◽  
Caroline Thielen ◽  
Thouraya Labiet ◽  
Sabine Eisher ◽  
Olivier Jolois ◽  
...  
Keyword(s):  
Prion Protein ◽  
Immune Cells ◽  
Surface Protein ◽  
In Vitro Study ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Lymphoid Tissues ◽  
Spongiform Encephalopathies ◽  
Bovine Lymphocytes

The cellular prion protein (PrPc) is a glycolipid-anchored cell surface protein that usually exhibits three glycosylation states. Its post-translationally modified isoform, PrPsc, is involved in the pathogenesis of various transmissible spongiform encephalopathies (TSEs). In bovine species, BSE infectivity appears to be restricted to the central nervous system; few or no detectable infectivity is found in lymphoid tissues in contrast to scrapie or variant CJD. Since expression of PrPc is a prerequisite for prion replication, we have investigated PrPc expression by bovine immune cells. Lymphocytes from blood and five different lymph organs were isolated from the same animal to assess intra- and interindividual variability of PrPc expression, considering six individuals. As shown by flow cytometry, this expression is absent or weak on granulocytes but is measurable on monocytes, B and T cells from blood and lymph organs. The activation of the bovine cells produces an upregulation of PrPc. The results of our in vitro study of PrPc biosynthesis are consistent with previous studies in other species. Interestingly, western blotting experiments showed only one form of the protein, the diglycosylated band. We propose that the glycosylation state could explain the lack of infectivity of the bovine immune cells.

scholarly journals A Promising Antiprion Trimethoxychalcone Binds to the Globular Domain of the Cellular Prion Protein and Changes Its Cellular Location

2017 ◽  
Vol 62 (2) ◽  
Author(s):  
N. C. Ferreira ◽  
L. M. Ascari ◽  
A. G. Hughson ◽  
G. R. Cavalheiro ◽  
C. F. Góes ◽  
...  
Keyword(s):  
Cell Surface ◽  
Real Time ◽  
Prion Protein ◽  
Molecular Mechanisms ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Globular Domain ◽  
Mrna Levels ◽  
Spongiform Encephalopathies

ABSTRACTThe search for antiprion compounds has been encouraged by the fact that transmissible spongiform encephalopathies (TSEs) share molecular mechanisms with more prevalent neurodegenerative pathologies, such as Parkinson's and Alzheimer's diseases. Cellular prion protein (PrPC) conversion into protease-resistant forms (protease-resistant PrP [PrPRes] or the scrapie form of PrP [PrPSc]) is a critical step in the development of TSEs and is thus one of the main targets in the screening for antiprion compounds. In this work, three trimethoxychalcones (compounds J1, J8, and J20) and one oxadiazole (compound Y17), previously identifiedin vitroto be potential antiprion compounds, were evaluated through different approaches in order to gain inferences about their mechanisms of action. None of them changed PrPCmRNA levels in N2a cells, as shown by reverse transcription-quantitative real-time PCR. Among them, J8 and Y17 were effective in real-time quaking-induced conversion reactions using rodent recombinant PrP (rPrP) from residues 23 to 231 (rPrP23–231) as the substrate and PrPScseeds from hamster and human brain. However, when rPrP from residues 90 to 231 (rPrP90–231), which lacks the N-terminal domain, was used as the substrate, only J8 remained effective, indicating that this region is important for Y17 activity, while J8 seems to interact with the PrPCglobular domain. J8 also reduced the fibrillation of mouse rPrP23–231seeded within vitro-produced fibrils. Furthermore, most of the compounds decreased the amount of PrPCon the N2a cell surface by trapping this protein in the endoplasmic reticulum. On the basis of these results, we hypothesize that J8, a nontoxic compound previously shown to be a promising antiprion agent, may act by different mechanisms, since its efficacy is attributable not only to PrP conversion inhibition but also to a reduction of the PrPCcontent on the cell surface.

scholarly journals Neuroprotective role of PrPC against kainate-induced epileptic seizures and cell death depends on the modulation of JNK3 activation by GluR6/7–PSD-95 binding

2011 ◽  
Vol 22 (17) ◽  
pp. 3041-3054 ◽  
Author(s):  
Patricia Carulla ◽  
Ana Bribián ◽  
Alejandra Rangel ◽  
Rosalina Gavín ◽  
Isidro Ferrer ◽  
...  
Keyword(s):  
Prion Protein ◽  
Knockout Mice ◽  
Neuronal Excitability ◽  
Epileptic Seizures ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathies ◽  
Glycosyl Phosphatidylinositol

Cellular prion protein (PrPC) is a glycosyl-phosphatidylinositol–anchored glycoprotein. When mutated or misfolded, the pathogenic form (PrPSC) induces transmissible spongiform encephalopathies. In contrast, PrPC has a number of physiological functions in several neural processes. Several lines of evidence implicate PrPC in synaptic transmission and neuroprotection since its absence results in an increase in neuronal excitability and enhanced excitotoxicity in vitro and in vivo. Furthermore, PrPC has been implicated in the inhibition of N-methyl-d-aspartic acid (NMDA)–mediated neurotransmission, and prion protein gene (Prnp) knockout mice show enhanced neuronal death in response to NMDA and kainate (KA). In this study, we demonstrate that neurotoxicity induced by KA in Prnp knockout mice depends on the c-Jun N-terminal kinase 3 (JNK3) pathway since Prnpo/oJnk3o/o mice were not affected by KA. Pharmacological blockage of JNK3 activity impaired PrPC-dependent neurotoxicity. Furthermore, our results indicate that JNK3 activation depends on the interaction of PrPC with postsynaptic density 95 protein (PSD-95) and glutamate receptor 6/7 (GluR6/7). Indeed, GluR6–PSD-95 interaction after KA injections was favored by the absence of PrPC. Finally, neurotoxicity in Prnp knockout mice was reversed by an AMPA/KA inhibitor (6,7-dinitroquinoxaline-2,3-dione) and the GluR6 antagonist NS-102. We conclude that the protection afforded by PrPC against KA is due to its ability to modulate GluR6/7-mediated neurotransmission and hence JNK3 activation.

scholarly journals New inhibitors of prion replication that target the amyloid precursor

2009 ◽  
Vol 90 (5) ◽  
pp. 1294-1301 ◽  
Author(s):  
Mathieu Charvériat ◽  
Marlène Reboul ◽  
Qian Wang ◽  
Christèle Picoli ◽  
Natacha Lenuzza ◽  
...  
Keyword(s):  
Protein Stability ◽  
Prion Protein ◽  
Prion Diseases ◽  
Direct Interaction ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathies ◽  
Regulatory Pathways ◽  
Erythromycin A

At present, there is no effective therapy for any of the neurodegenerative amyloidoses, despite renewed efforts to identify compounds active against the various implicated pathogenetic molecules. We have screened a library of 2960 natural and synthetic compounds in two cell lines chronically infected with mouse prions, and have identified eight new inhibitors of prion replication in vitro. They belong to two distinct chemical families that have not previously been recognised as effective in the field of transmissible spongiform encephalopathies: seven are 3-aminosteroids and one is a derivative of erythromycin A with an oxime functionality. Our results suggest that these aminosteroids inhibit prion replication by triggering a common target, possibly implicated in the regulatory pathways of cellular prion protein metabolism. Furthermore, using a quantitative approach for the study of protein stability, it was shown that the erythromycin A derivative altered prion protein stability by direct interaction. Such direct targeting of this amyloid precursor might provide new clues for the understanding of prion diseases and, more importantly, help to define new molecules that are active against prion diseases.

scholarly journals In Vitro Approach To Identify Key Amino Acids in Low Susceptibility of Rabbit Prion Protein to Misfolding

2017 ◽  
Vol 91 (24) ◽  
Author(s):  
Hasier Eraña ◽  
Natalia Fernández-Borges ◽  
Saioa R. Elezgarai ◽  
Chafik Harrathi ◽  
Jorge M. Charco ◽  
...  
Keyword(s):  
Amino Acid ◽  
Prion Protein ◽  
Amino Acid Residue ◽  
Cellular Prion Protein ◽  
Single Amino Acid ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Experimental Conditions ◽  
Spongiform Encephalopathies

ABSTRACT Prion diseases, or transmissible spongiform encephalopathies (TSEs), are a group of rare progressive neurodegenerative disorders caused by an abnormally folded prion protein (PrPSc). This is capable of transforming the normal cellular prion protein (PrPC) into new infectious PrPSc. Interspecies prion transmissibility studies performed by experimental challenge and the outbreak of bovine spongiform encephalopathy that occurred in the late 1980s and 1990s showed that while some species (sheep, mice, and cats) are readily susceptible to TSEs, others are apparently resistant (rabbits, dogs, and horses) to the same agent. To study the mechanisms of low susceptibility to TSEs of certain species, the mouse-rabbit transmission barrier was used as a model. To identify which specific amino acid residues determine high or low susceptibility to PrPSc propagation, protein misfolding cyclic amplification (PMCA), which mimics PrPC-to-PrPSc conversion with accelerated kinetics, was used. This allowed amino acid substitutions in rabbit PrP and accurate analysis of misfolding propensities. Wild-type rabbit recombinant PrP could not be misfolded into a protease-resistant self-propagating isoform in vitro despite seeding with at least 12 different infectious prions from diverse origins. Therefore, rabbit recombinant PrP mutants were designed to contain every single amino acid substitution that distinguishes rabbit recombinant PrP from mouse recombinant PrP. Key amino acid residue substitutions were identified that make rabbit recombinant PrP susceptible to misfolding, and using these, protease-resistant misfolded recombinant rabbit PrP was generated. Additional studies characterized the mechanisms by which these critical amino acid residue substitutions increased the misfolding susceptibility of rabbit PrP. IMPORTANCE Prion disorders are invariably fatal, untreatable diseases typically associated with long incubation periods and characteristic spongiform changes associated with neuronal loss in the brain. Development of any treatment or preventative measure is dependent upon a detailed understanding of the pathogenesis of these diseases, and understanding the mechanism by which certain species appear to be resistant to TSEs is critical. Rabbits are highly resistant to naturally acquired TSEs, and even under experimental conditions, induction of clinical disease is not easy. Using recombinant rabbit PrP as a model, this study describes critical molecular determinants that confer this high resistance to transmissible spongiform encephalopathies.

scholarly journals Characterization of the role of dendritic cells in prion transfer to primary neurons

2010 ◽  
Vol 431 (2) ◽  
pp. 189-198 ◽  
Author(s):  
Christelle Langevin ◽  
Karine Gousset ◽  
Maddalena Costanzo ◽  
Odile Richard-Le Goff ◽  
Chiara Zurzolo
Keyword(s):  
Nervous System ◽  
Dendritic Cells ◽  
Prion Protein ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Cell Contact ◽  
Neuronal Cultures ◽  
Lymphoid Tissues ◽  
Spongiform Encephalopathies

TSEs (transmissible spongiform encephalopathies) are neurodegenerative diseases caused by pathogenic isoforms (PrPSc) of the host-encoded PrPc (cellular prion protein). After consumption of contaminated food, PrPSc deposits rapidly accumulate in lymphoid tissues before invasion of the CNS (central nervous system). However, the mechanisms of prion spreading from the periphery to the nervous system are still unclear. In the present study, we investigated the role of DCs (dendritic cells) in the spreading of prion infection to neuronal cells. First, we determined that BMDCs (bone-marrow-derived DCs) rapidly uptake PrPSc after exposure to infected brain homogenate. Next, we observed a progressive catabolism of the internalized prion aggregates. Similar experiments performed with BMDCs isolated from KO (knockout) mice or mice overexpressing PrP (tga20) indicate that both PrPSc uptake and catabolism are independent of PrPc expression in these cells. Finally, using co-cultures of prion-loaded BMDCs and cerebellar neurons, we characterized the transfer of the prion protein and the resulting infection of the neuronal cultures. Interestingly, the transfer of PrPSc was triggered by direct cell–cell contact. As a consequence, BMDCs retained the prion protein when cultured alone, and no transfer to the recipient neurons was observed when a filter separated the two cultures or when neurons were exposed to the BMDC-conditioned medium. Additionally, fixed BMDCs also failed to transfer prion infectivity to neurons, suggesting an active transport of prion aggregates, in accordance with a role of TNTs (tunnelling nanotubes) observed in the co-cultures.

scholarly journals Effect of Scrapie Prion Infection in Ovine Bone Marrow-Derived Mesenchymal Stem Cells and Ovine Mesenchymal Stem Cell-Derived Neurons

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1137
Author(s):  
Laura García-Mendívil ◽  
Diego R. Mediano ◽  
Adelaida Hernaiz ◽  
David Sanz-Rubio ◽  
Francisco J. Vázquez ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Post Inoculation ◽  
Spongiform Encephalopathies ◽  
Prion Infection ◽  
Over Time

Scrapie is a prion disease affecting sheep and goats and it is considered a prototype of transmissible spongiform encephalopathies (TSEs). Mesenchymal stem cells (MSCs) have been proposed as candidates for developing in vitro models of prion diseases. Murine MSCs are able to propagate prions after previous mouse-adaptation of prion strains and, although ovine MSCs express the cellular prion protein (PrPC), their susceptibility to prion infection has never been investigated. Here, we analyze the potential of ovine bone marrow-derived MSCs (oBM-MSCs), in growth and neurogenic conditions, to be infected by natural scrapie and propagate prion particles (PrPSc) in vitro, as well as the effect of this infection on cell viability and proliferation. Cultures were kept for 48–72 h in contact with homogenates of central nervous system (CNS) samples from scrapie or control sheep. In growth conditions, oBM-MSCs initially maintained detectable levels of PrPSc post-inoculation, as determined by Western blotting and ELISA. However, the PrPSc signal weakened and was lost over time. oBM-MSCs infected with scrapie displayed lower cell doubling and higher doubling times than those infected with control inocula. On the other hand, in neurogenic conditions, oBM-MSCs not only maintained detectable levels of PrPSc post-inoculation, as determined by ELISA, but this PrPSc signal also increased progressively over time. Finally, inoculation with CNS extracts seems to induce the proliferation of oBM-MSCs in both growth and neurogenic conditions. Our results suggest that oBM-MSCs respond to prion infection by decreasing their proliferation capacity and thus might not be permissive to prion replication, whereas ovine MSC-derived neuron-like cells seem to maintain and replicate PrPSc.

scholarly journals The Prion Protein Octarepeat Domain Forms Transient β-sheet Structures Upon Residue-Specific Cu(II) and Zn(II) Binding

2021 ◽  
Author(s):  
Maciej Gielnik ◽  
Aneta Szymanska ◽  
Xiaolin Dong ◽  
Jyri Jarvet ◽  
Zeljko M. Svedruzic ◽  
...  
Keyword(s):  
Metal Ions ◽  
Prion Protein ◽  
Metal Binding ◽  
Cd Spectroscopy ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Amyloid Formation ◽  
Spectroscopy Data ◽  
Spongiform Encephalopathies ◽  
Β Sheet

Misfolding of the cellular prion protein (PrPC) is associated with the development of fatal neurodegenerative diseases called transmissible spongiform encephalopathies (TSEs). Metal ions appear to play a crucial role in the protein misfolding, and metal imbalance may be part of TSE pathologies. PrPC is a combined Cu(II) and Zn(II) metal binding protein, where the main metal binding site is located in the octarepeat (OR) region. Here, we used biophysical methods to characterize Cu(II) and Zn(II) binding to the isolated OR region. Circular dichroism (CD) spectroscopy data suggest that the OR domain binds up to four Cu(II) ions or two Zn(II) ions. Upon metal binding, the OR region seems to adopt a transient antiparallel β-sheet hairpin structure. Fluorescence spectroscopy data indicates that under neutral conditions, the OR region can bind both Cu(II) and Zn(II) ions, whereas under acidic conditions it binds only Cu(II) ions. Molecular dynamics simulations suggest that binding of both metal ions to the OR region results in formation of β-hairpin structures. As formation of β-sheet structures is a first step towards amyloid formation, we propose that high concentrations of either Cu(II) or Zn(II) ions may have a pro-amyloid effect in TSEs.

scholarly journals Zn(II) binding causes interdomain changes in the structure and flexibility of the human prion protein

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maciej Gielnik ◽  
Michał Taube ◽  
Lilia Zhukova ◽  
Igor Zhukov ◽  
Sebastian K. T. S. Wärmländer ◽  
...  
Keyword(s):  
Prion Protein ◽  
Metal Ion ◽  
Structural Transition ◽  
Cellular Prion Protein ◽  
Zinc Homeostasis ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathies ◽  
Structural Conversion ◽  
Protein Size ◽  
Dynamics Simulations

AbstractThe cellular prion protein (PrPC) is a mainly α-helical 208-residue protein located in the pre- and postsynaptic membranes. For unknown reasons, PrPC can undergo a structural transition into a toxic, β-sheet rich scrapie isoform (PrPSc) that is responsible for transmissible spongiform encephalopathies (TSEs). Metal ions seem to play an important role in the structural conversion. PrPC binds Zn(II) ions and may be involved in metal ion transport and zinc homeostasis. Here, we use multiple biophysical techniques including optical and NMR spectroscopy, molecular dynamics simulations, and small angle X-ray scattering to characterize interactions between human PrPC and Zn(II) ions. Binding of a single Zn(II) ion to the PrPC N-terminal domain via four His residues from the octarepeat region induces a structural transition in the C-terminal α-helices 2 and 3, promotes interaction between the N-terminal and C-terminal domains, reduces the folded protein size, and modifies the internal structural dynamics. As our results suggest that PrPC can bind Zn(II) under physiological conditions, these effects could be important for the physiological function of PrPC.

scholarly journals Sulphated glycosaminoglycans prevent the neurotoxicity of a human prion protein fragment

1998 ◽  
Vol 335 (2) ◽  
pp. 369-374 ◽  
Author(s):  
Mar PÉREZ ◽  
Francisco WANDOSELL ◽  
Camilo COLAÇO ◽  
Jesús AVILA
Keyword(s):  
Prion Protein ◽  
Amyloid Fibrils ◽  
Transmissible Spongiform Encephalopathies ◽  
Therapeutic Effects ◽  
Protein Fragment ◽  
Spongiform Encephalopathies ◽  
Sulphated Polysaccharides ◽  
Human Prion Protein ◽  
Sulphated Glycosaminoglycans

Although a number of features distinguish the disease isoform of the prion protein (PrPSc) from its normal cellular counterpart (PrPC) in the transmissible spongiform encephalopathies (TSEs), the neuropathogenesis of these diseases remains an enigma. The amyloid fibrils formed by fragments of human PrP have, however, been shown to be directly neurotoxic in vitro. We show here that sulphated polysaccharides (heparin, keratan and chondroitin) inhibit the neurotoxicity of these amyloid fibrils and this appears to be mediated via inhibition of the polymerization of the PrP peptide into fibrils. This provides a rationale for the therapeutic effects of sulphated polysaccharides and suggests a rapid in vitro functional screen for TSE therapeutics.

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