scholarly journals Toxicological Evaluation of Anti-Scrapie Trimethoxychalcones and Oxadiazoles

2015 ◽  
Vol 87 (2 suppl) ◽  
pp. 1421-1434 ◽  
Author(s):  
CLAUDIA P. FIGUEIREDO ◽  
NATALIA C. FERREIRA ◽  
GISELLE F. PASSOS ◽  
ROBSON DA COSTA ◽  
FERNANDA S. NEVES ◽  
...  
Keyword(s):  
Prion Protein ◽  
Aromatic Compounds ◽  
Prion Diseases ◽  
Intraperitoneal Administration ◽  
Neuroblastoma Cells ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Toxicological Evaluation ◽  
Spongiform Encephalopathies

An altered form of the cellular prion protein, the PrPScor PrPRes, is implicated in the occurrence of the still untreatable transmissible spongiform encephalopathies. We have previously synthesized and characterized aromatic compounds that inhibit protease-resistant prion protein (PrPRes) accumulation in scrapie-infected cells. These compounds belong to different chemical classes, including acylhydrazones, chalcones and oxadiazoles. Some of the active compounds were non-toxic to neuroblastoma cells in culture and seem to possess drugable properties, since they are in agreement with the Lipinski´s rule of 5 and present desirable pharmacokinetic profiles as predicted in silico. Before the evaluation of the in vivo efficacy of the aromatic compounds in scrapie-infected mice, safety assessment in healthy mice is needed. Here we used Swiss mice to evaluate the acute toxicity profile of the six most promising anti-prionic compounds, the 2,4,5-trimethoxychalcones (J1, J8, J20 and J35) and the 1,3,4-oxadiazoles (Y13 and Y17). One single oral administration (300 mg/kg) of J1, J8, J20, J35, Y13 and Y17 or repeated intraperitoneal administration (10 mg/kg, 3 times a week, for 4 weeks) of J1, J8 and J35, did not elicit toxicity in mice. We strongly believe that the investigated trimethoxychalcones and oxadiazoles are interesting compounds to be further analyzed in vivo against prion diseases.

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 Cells Expressing Anchorless Prion Protein Are Resistant to Scrapie Infection

2009 ◽  
Vol 83 (9) ◽  
pp. 4469-4475 ◽  
Author(s):  
Kristin L. McNally ◽  
Anne E. Ward ◽  
Suzette A. Priola
Keyword(s):  
Transgenic Mice ◽  
Prion Protein ◽  
Prion Diseases ◽  
Transmitted Disease ◽  
Transmissible Spongiform Encephalopathies ◽  
Gpi Anchor ◽  
Spongiform Encephalopathies ◽  
Infected Cells

ABSTRACT The hallmark of transmissible spongiform encephalopathies (TSEs or prion diseases) is the accumulation of an abnormally folded, partially protease-resistant form (PrP-res) of the normal protease-sensitive prion protein (PrP-sen). PrP-sen is attached to the cell membrane by a glycosylphosphatidylinositol (GPI) anchor. In vitro, the anchor and the local membrane environment are important for the conversion of PrP-sen to PrP-res. In vivo, however, the anchor is not necessary because transgenic mice expressing anchorless PrP-sen accumulate PrP-res and replicate infectivity. To clarify the role of the GPI anchor in TSE infection, cells expressing GPI-anchored PrP-sen, anchorless PrP-sen, or both forms of PrP-sen were exposed to the mouse scrapie strain 22L. Cells expressing anchored PrP-sen produced PrP-res after exposure to 22L. Surprisingly, while cells expressing anchorless PrP-sen made anchorless PrP-res in the first 96 h postinfection, no PrP-res was detected at later passes. In contrast, when cells expressing both forms of PrP-sen were exposed to 22L, both anchored and anchorless PrP-res were detected over multiple passes. Consistent with the in vitro data, scrapie-infected cells expressing anchored PrP-sen transmitted disease to mice whereas cells expressing anchorless PrP-sen alone did not. These results demonstrate that the GPI anchor on PrP-sen is important for the persistent infection of cells in vitro. Our data suggest that cells expressing anchorless PrP-sen are not directly infected with scrapie. Thus, PrP-res formation in transgenic mice expressing anchorless PrP-sen may be occurring extracellularly.

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 Prion disease and endoplasmic reticulum stress pathway correlations and treatment pursuits

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Tarah Satterfield ◽  
Jessica Pritchett ◽  
Sarah Cruz ◽  
Kyeorda Kemp
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Prion Protein ◽  
Prion Disease ◽  
Prion Diseases ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Protein Accumulation ◽  
Spongiform Encephalopathies ◽  
Unfolded Protein

AbstractBackground: Transmissible spongiform encephalopathies are a collection of rare neurodegenerative disorders characterized by loss of neuronal cells, astrocytosis, and plaque formation. The causative agent of these diseases is thought to be abnormally folded prions and is characterized by a conformational change from normal, cellular prion protein (PrPc) to the abnormal form (PrPTSE). Although, there is evidence that normal prion protein can contribute to these disorders. The unfolded protein response, a conserved series of pathways involved in resolving stress associated with unfolded protein accumulation in the Endoplasmic Reticulum (ER), has been shown to play a role in regulating the development of prion diseases. Methods: This review chose papers based on their relevance to current studies involved in prion protein synthesis and transformation, identifies various links between prion diseases and ER stress, and reports on current and potential treatments as they relate to ER stress and prion diseases. Conclusion: For the advancement of prion disease treatment, it is important to understand the mechanisms involved in prion formation, and ER stress is implicated in prion disease progression. Therefore, targeting the ER or pathways involved in response to stress in the ER may help us treat prion diseases.

scholarly journals Backbone NMR assignments of the C-terminal domain of the human prion protein and its disease‐associated T183A variant

2021 ◽  
Vol 15 (1) ◽  
pp. 193-196
Author(s):  
Máximo Sanz-Hernández ◽  
Alfonso De Simone
Keyword(s):  
Prion Protein ◽  
Nmr Assignments ◽  
Chemical Shifts ◽  
Prion Diseases ◽  
Random Coil ◽  
Transmissible Spongiform Encephalopathies ◽  
Globular Domain ◽  
Structural Elements ◽  
Spongiform Encephalopathies ◽  
Human Prion Protein

AbstractTransmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders associated with the misfolding and aggregation of the human prion protein (huPrP). Despite efforts into investigating the process of huPrP aggregation, the mechanisms triggering its misfolding remain elusive. A number of TSE-associated mutations of huPrP have been identified, but their role at the onset and progression of prion diseases is unclear. Here we report the NMR assignments of the C-terminal globular domain of the wild type huPrP and the pathological mutant T183A. The differences in chemical shifts between the two variants reveal conformational alterations in some structural elements of the mutant, whereas the analyses of secondary shifts and random coil index provide indications on the putative mechanisms of misfolding of T183A huPrP.

scholarly journals Prion Disease Blood Test Using Immunoprecipitation and Improved Quaking-Induced Conversion

mBio ◽  
2011 ◽  
Vol 2 (3) ◽  
Author(s):  
Christina D. Orrú ◽  
Jason M. Wilham ◽  
Lynne D. Raymond ◽  
Franziska Kuhn ◽  
Björn Schroeder ◽  
...  
Keyword(s):  
Real Time ◽  
Blood Test ◽  
Prion Diseases ◽  
Proteinase K ◽  
Transmissible Spongiform Encephalopathies ◽  
Serum Samples ◽  
Spongiform Encephalopathies ◽  
Jakob Disease

ABSTRACT A key challenge in managing transmissible spongiform encephalopathies (TSEs) or prion diseases in medicine, agriculture, and wildlife biology is the development of practical tests for prions that are at or below infectious levels. Of particular interest are tests capable of detecting prions in blood components such as plasma, but blood typically has extremely low prion concentrations and contains inhibitors of the most sensitive prion tests. One of the latter tests is quaking-induced conversion (QuIC), which can be as sensitive as in vivo bioassays, but much more rapid, higher throughput, and less expensive. Now we have integrated antibody 15B3-based immunoprecipitation with QuIC reactions to increase sensitivity and isolate prions from inhibitors such as those in plasma samples. Coupling of immunoprecipitation and an improved real-time QuIC reaction dramatically enhanced detection of variant Creutzfeldt-Jakob disease (vCJD) brain tissue diluted into human plasma. Dilutions of 1014-fold, containing ~2 attogram (ag) per ml of proteinase K-resistant prion protein, were readily detected, indicating ~10,000-fold greater sensitivity for vCJD brain than has previously been reported. We also discriminated between plasma and serum samples from scrapie-infected and uninfected hamsters, even in early preclinical stages. This combined assay, which we call “enhanced QuIC” (eQuIC), markedly improves prospects for routine detection of low levels of prions in tissues, fluids, or environmental samples. IMPORTANCE Transmissible spongiform encephalopathies (TSEs) are largely untreatable and are difficult to diagnose definitively prior to irreversible clinical decline or death. The transmissibility of TSEs within and between species highlights the need for practical tests for even the smallest amounts of infectivity. A few sufficiently sensitive in vitro methods have been reported, but most have major limitations that would preclude their use in routine diagnostic or screening applications. Our new assay improves the outlook for such critical applications. We focused initially on blood plasma because a practical blood test for prions would be especially valuable for TSE diagnostics and risk reduction. Variant Creutzfeldt-Jakob disease (vCJD) in particular has been transmitted between humans via blood transfusions. Enhanced real-time quaking-induced conversion (eRTQ) provides by far the most sensitive detection of vCJD to date. The 15B3 antibody binds prions of multiple species, suggesting that our assay may be useful for clinical and fundamental studies of a variety of TSEs of humans and animals.

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 Gene-Based Antibody Strategies for Prion Diseases

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Alessio Cardinale ◽  
Silvia Biocca
Keyword(s):  
Therapeutic Potential ◽  
Prion Diseases ◽  
Recombinant Antibody ◽  
Cellular Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Diagnostic Tools ◽  
Spongiform Encephalopathies ◽  
Interaction Sites

Prion diseases or transmissible spongiform encephalopathies (TSE) are a group of neurodegenerative and infectious disorders characterized by the conversion of a normal cellular protein PrPCinto a pathological abnormally folded form, termed PrPSc. There are neither available therapies nor diagnostic tools for an early identification of individuals affected by these diseases. New gene-based antibody strategies are emerging as valuable therapeutic tools. Among these, intrabodies are chimeric molecules composed by recombinant antibody fragments fused to intracellular trafficking sequences, aimed at inhibiting,in vivo, the function of specific therapeutic targets. The advantage of intrabodies is that they can be selected against a precise epitope of target proteins, including protein-protein interaction sites and cytotoxic conformers (i.e., oligomeric and fibrillar assemblies). Herein, we address and discussin vitroandin vivoapplications of intrabodies in prion diseases, focussing on their therapeutic potential.

scholarly journals Dimerization of the cellular prion protein inhibits propagation of scrapie prions

2018 ◽  
Vol 293 (21) ◽  
pp. 8020-8031 ◽  
Author(s):  
Anna D. Engelke ◽  
Anika Gonsberg ◽  
Simrika Thapa ◽  
Sebastian Jung ◽  
Sarah Ulbrich ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Prion Protein ◽  
Conformational Transition ◽  
Prion Diseases ◽  
Neuroblastoma Cells ◽  
Direct Interaction ◽  
Cellular Prion Protein ◽  
Dominant Negative ◽  
Dimerization Domain ◽  
Hydrophobic Domain

A central step in the pathogenesis of prion diseases is the conformational transition of the cellular prion protein (PrPC) into the scrapie isoform, denoted PrPSc. Studies in transgenic mice have indicated that this conversion requires a direct interaction between PrPC and PrPSc; however, insights into the underlying mechanisms are still missing. Interestingly, only a subfraction of PrPC is converted in scrapie-infected cells, suggesting that not all PrPC species are suitable substrates for the conversion. On the basis of the observation that PrPC can form homodimers under physiological conditions with the internal hydrophobic domain (HD) serving as a putative dimerization domain, we wondered whether PrP dimerization is involved in the formation of neurotoxic and/or infectious PrP conformers. Here, we analyzed the possible impact on dimerization of pathogenic mutations in the HD that induce a spontaneous neurodegenerative disease in transgenic mice. Similarly to wildtype (WT) PrPC, the neurotoxic variant PrP(AV3) formed homodimers as well as heterodimers with WTPrPC. Notably, forced PrP dimerization via an intermolecular disulfide bond did not interfere with its maturation and intracellular trafficking. Covalently linked PrP dimers were complex glycosylated, GPI-anchored, and sorted to the outer leaflet of the plasma membrane. However, forced PrPC dimerization completely blocked its conversion into PrPSc in chronically scrapie-infected mouse neuroblastoma cells. Moreover, PrPC dimers had a dominant-negative inhibition effect on the conversion of monomeric PrPC. Our findings suggest that PrPC monomers are the major substrates for PrPSc propagation and that it may be possible to halt prion formation by stabilizing PrPC dimers.

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.

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