Browse
Submit Data
Databases
API
Help

Dataset Information

38 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Polythiophenes inhibit prion propagation by stabilizing prion protein (PrP) aggregates.

ABSTRACT: Luminescent conjugated polymers (LCPs) interact with ordered protein aggregates and sensitively detect amyloids of many different proteins, suggesting that they may possess antiprion properties. Here, we show that a variety of anionic, cationic, and zwitterionic LCPs reduced the infectivity of prion-containing brain homogenates and of prion-infected cerebellar organotypic cultured slices and decreased the amount of scrapie isoform of PrP(C) (PrP(Sc)) oligomers that could be captured in an avidity assay. Paradoxically, treatment enhanced the resistance of PrP(Sc) to proteolysis, triggered the compaction, and enhanced the resistance to proteolysis of recombinant mouse PrP(23-231) fibers. These results suggest that LCPs act as antiprion agents by transitioning PrP aggregates into structures with reduced frangibility. Moreover, ELISA on cerebellar organotypic cultured slices and in vitro conversion assays with mouse PrP(23-231) indicated that poly(thiophene-3-acetic acid) may additionally interfere with the generation of PrP(Sc) by stabilizing the conformation of PrP(C) or of a transition intermediate. Therefore, LCPs represent a novel class of antiprion agents whose mode of action appears to rely on hyperstabilization, rather than destabilization, of PrP(Sc) deposits.

SUBMITTER: Margalith I

PROVIDER: S-EPMC3365923 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Soluble A? aggregates can inhibit prion propagation.

Project description:Mammalian prions cause lethal neurodegenerative diseases such as Creutzfeldt-Jakob disease (CJD) and consist of multi-chain assemblies of misfolded cellular prion protein (PrPC). Ligands that bind to PrPC can inhibit prion propagation and neurotoxicity. Extensive prior work established that certain soluble assemblies of the Alzheimer's disease (AD)-associated amyloid ?-protein (A?) can tightly bind to PrPC, and that this interaction may be relevant to their toxicity in AD. Here, we investigated whether such soluble A? assemblies might, conversely, have an inhibitory effect on prion propagation. Using cellular models of prion infection and propagation and distinct A? preparations, we found that the form of A? assemblies which most avidly bound to PrP in vitro also inhibited prion infection and propagation. By contrast, forms of A? which exhibit little or no binding to PrP were unable to attenuate prion propagation. These data suggest that soluble aggregates of A? can compete with prions for binding to PrPC and emphasize the bidirectional nature of the interplay between A? and PrPC in Alzheimer's and prion diseases. Such inhibitory effects of A? on prion propagation may contribute to the apparent fall-off in the incidence of sporadic CJD at advanced age where cerebral A? deposition is common.

| S-EPMC5717343 | biostudies-literature

Mammalian prion propagation in PrP transgenic Drosophila.

Project description:Mammalian prions propagate by template-directed misfolding and aggregation of normal cellular prion related protein PrPC as it converts into disease-associated conformers collectively referred to as PrPSc. Mammalian species may be permissive for prion disease because these hosts have co-evolved specific co-factors that assist PrPC conformational change and prion propagation. We have tested this hypothesis by examining whether faithful prion propagation occurs in the normally PrPC-null invertebrate host Drosophila melanogaster. Ovine PrP transgenic Drosophila exposed at the larval stage to ovine scrapie showed a progressive accumulation of transmissible prions in adult flies. Strikingly, the biological properties of distinct ovine prion strains were maintained during their propagation in Drosophila. Our observations show that the co-factors necessary for strain-specific prion propagation are not unique to mammalian species. Our studies establish Drosophila as a novel host for the study of transmissible mammalian prions.

| S-EPMC6113635 | biostudies-literature

Mammalian prion protein (PrP) forms conformationally different amyloid intracellular aggregates in bacteria.

Project description:An increasing number of proteins are being shown to assemble into amyloid structures that lead to pathological states. Among them, mammalian prions outstand due to their ability to transmit the pathogenic conformation, becoming thus infectious. The structural conversion of the cellular prion protein (PrP(C)), into its misfolded pathogenic form (PrP(Sc)) is the central event of prion-driven pathologies. The study of the structural properties of intracellular amyloid aggregates in general and of prion-like ones in particular is a challenging task. In this context, the evidence that the inclusion bodies formed by amyloid proteins in bacteria display amyloid-like structural and functional properties make them a privileged system to model intracellular amyloid aggregation.Here we provide the first demonstration that recombinant murine PrP and its C-terminal domain (90-231) attain amyloid conformations inside bacteria. Moreover, the inclusions formed by these two PrP proteins display conformational diversity, since they differ in fibril morphology, binding affinity to amyloid dyes, stability, resistance to proteinase K digestion and neurotoxicity.Overall, our results suggest that modelling PrP amyloid formation in microbial cell factories might open an avenue for a better understanding of the structural features modulating the pathogenic impact of this intriguing protein.

| S-EPMC4634817 | biostudies-literature

Anti-prion Protein Antibody 6D11 Restores Cellular Proteostasis of Prion Protein Through Disrupting Recycling Propagation of PrP<sup>Sc</sup> and Targeting PrP<sup>Sc</sup> for Lysosomal Degradation.

Project description:PrPSc is an infectious and disease-specific conformer of the prion protein, which accumulation in the CNS underlies the pathology of prion diseases. PrPSc replicates by binding to the cellular conformer of the prion protein (PrPC) expressed by host cells and rendering its secondary structure a likeness of itself. PrPC is a plasma membrane anchored protein, which constitutively recirculates between the cell surface and the endocytic compartment. Since PrPSc engages PrPC along this trafficking pathway, its replication process is often referred to as "recycling propagation." Certain monoclonal antibodies (mAbs) directed against prion protein can abrogate the presence of PrPSc from prion-infected cells. However, the precise mechanism(s) underlying their therapeutic propensities remains obscure. Using N2A murine neuroblastoma cell line stably infected with 22L mouse-adapted scrapie strain (N2A/22L), we investigated here the modus operandi of the 6D11 clone, which was raised against the PrPSc conformer and has been shown to permanently clear prion-infected cells from PrPSc presence. We determined that 6D11 mAb engages and sequesters PrPC and PrPSc at the cell surface. PrPC/6D11 and PrPSc/6D11 complexes are then endocytosed from the plasma membrane and are directed to lysosomes, therefore precluding recirculation of nascent PrPSc back to the cell surface. Targeting PrPSc by 6D11 mAb to the lysosomal compartment facilitates its proteolysis and eventually shifts the balance between PrPSc formation and degradation. Ongoing translation of PrPC allows maintaining the steady-state level of prion protein within the cells, which was not depleted under 6D11 mAb treatment. Our findings demonstrate that through disrupting recycling propagation of PrPSc and promoting its degradation, 6D11 mAb restores cellular proteostasis of prion protein.

| S-EPMC6326903 | biostudies-literature

Prion protein-Semisynthetic prion protein (PrP) variants with posttranslational modifications.

Project description:Deciphering the pathophysiologic events in prion diseases is challenging, and the role of posttranslational modifications (PTMs) such as glypidation and glycosylation remains elusive due to the lack of homogeneous protein preparations. So far, experimental studies have been limited in directly analyzing the earliest events of the conformational change of cellular prion protein (PrPC ) into scrapie prion protein (PrPSc ) that further propagates PrPC misfolding and aggregation at the cellular membrane, the initial site of prion infection, and PrP misfolding, by a lack of suitably modified PrP variants. PTMs of PrP, especially attachment of the glycosylphosphatidylinositol (GPI) anchor, have been shown to be crucially involved in the PrPSc formation. To this end, semisynthesis offers a unique possibility to understand PrP behavior invitro and invivo as it provides access to defined site-selectively modified PrP variants. This approach relies on the production and chemoselective linkage of peptide segments, amenable to chemical modifications, with recombinantly produced protein segments. In this article, advances in understanding PrP conversion using semisynthesis as a tool to obtain homogeneous posttranslationally modified PrP will be discussed.

| S-EPMC6899880 | biostudies-literature

Ovine recombinant PrP as an inhibitor of ruminant prion propagation in vitro.

Project description:Prion diseases are fatal and incurable neurodegenerative diseases of humans and animals. Despite years of research, no therapeutic agents have been developed that can effectively manage or reverse disease progression. Recently it has been identified that recombinant prion proteins (rPrP) expressed in bacteria can act as inhibitors of prion replication within the in vitro prion replication system protein misfolding cyclic amplification (PMCA). Here, within PMCA reactions amplifying a range of ruminant prions including distinct Prnp genotypes/host species and distinct prion strains, recombinant ovine VRQ PrP displayed consistent inhibition of prion replication and produced IC50 values of 122 and 171 nM for ovine scrapie and bovine BSE replication, respectively. These findings illustrate the therapeutic potential of rPrPs with distinct TSE diseases.

| S-EPMC5553304 | biostudies-other

Mouse prion protein (PrP) segment 100 to 104 regulates conversion of PrP(C) to PrP(Sc) in prion-infected neuroblastoma cells.

Project description:Prion diseases are characterized by the replicative propagation of disease-associated forms of prion protein (PrP(Sc); PrP refers to prion protein). The propagation is believed to proceed via two steps; the initial binding of the normal form of PrP (PrP(C)) to PrP(Sc) and the subsequent conversion of PrP(C) to PrP(Sc). We have explored the two-step model in prion-infected mouse neuroblastoma (ScN2a) cells by focusing on the mouse PrP (MoPrP) segment 92-GGTHNQWNKPSKPKTN-107, which is within a region previously suggested to be part of the binding interface or shown to differ in its accessibility to anti-PrP antibodies between PrP(C) and PrP(Sc). Exchanging the MoPrP segment with the corresponding chicken PrP segment (106-GGSYHNQKPWKPPKTN-121) revealed the necessity of MoPrP residues 99 to 104 for the chimeras to achieve the PrP(Sc) state, while segment 95 to 98 was replaceable with the chicken sequence. An alanine substitution at position 100, 102, 103, or 104 of MoPrP gave rise to nonconvertible mutants that associated with MoPrP(Sc) and interfered with the conversion of endogenous MoPrP(C). The interference was not evoked by a chimera (designated MCM2) in which MoPrP segment 95 to 104 was changed to the chicken sequence, though MCM2 associated with MoPrP(Sc). Incubation of the cells with a synthetic peptide composed of MoPrP residues 93 to 107 or alanine-substituted cognates did not inhibit the conversion, whereas an anti-P8 antibody recognizing the above sequence in PrP(C) reduced the accumulation of PrP(Sc) after 10 days of incubation of the cells. These results suggest the segment 100 to 104 of MoPrP(C) plays a key role in conversion after binding to MoPrP(Sc).

| S-EPMC3347255 | biostudies-literature

Prion-like propagation of ?-amyloid aggregates in the absence of APP overexpression.

Project description:The amyloid cascade hypothesis posits that the initiating event in Alzheimer's disease (AD) is the aggregation and deposition of the ?-amyloid (A?) peptide, which is a proteolytic cleavage product of the amyloid precursor protein (APP). Mounting evidence suggests that the formation and spread of prion-like A? aggregates during AD may contribute to disease progression. Inoculation of transgenic mice that overexpress APP with pre-formed A? aggregates results in the prion-like induction of cerebral A? deposition. To determine whether A? deposition can also be induced when physiological APP levels are present in the brain, we inoculated AppNL-F mice, a knock-in model of AD that avoids potential artifacts associated with APP overexpression, with A? aggregates derived from the brains of AD patients or transgenic mice. In all cases, induced A? deposition was apparent in the corpus callosum, olfactory bulb, and meningeal blood vessels of inoculated mice at 130-150 days post-inoculation, whereas uninoculated and buffer-inoculated animals exhibited minimal or no A? deposits at these ages. Interestingly, despite being predominantly composed of protease-resistant A?42 aggregates, the induced parenchymal A? deposits were largely diffuse and were unreactive to an amyloid-binding dye. These results demonstrate that APP overexpression is not a prerequisite for the prion-like induction of cerebral A? deposition. Accordingly, spreading of A? deposition may contribute to disease progression in AD patients.

| S-EPMC5883524 | biostudies-literature

Paracrine diffusion of PrP(C) and propagation of prion infectivity by plasma membrane-derived microvesicles.

Project description:Cellular prion protein (PrP(C)) is a physiological constituent of eukaryotic cells. The cellular pathways underlying prions spread from the sites of prions infection/peripheral replication to the central nervous system are still not elucidated. Membrane-derived microvesicles (MVs) are submicron (0.1-1 microm) particles, that are released by cells during plasma membrane shedding processes. They are usually liberated from different cell types, mainly upon activation as well as apoptosis, in this case, one of their hallmarks is the exposure of phosphatidylserine in the outer leaflet of the membrane. MVs are also characterized by the presence of adhesion molecules, MHC I molecules, as well as of membrane antigens typical of their cell of origin. Evidence exists that MVs shedding provide vehicles to transfer molecules among cells, and that MVs are important modulators of cell-to-cell communication. In this study we therefore analyzed the potential role of membrane-derived MVs in the mechanism(s) of PrP(C) diffusion and prion infectivity transmission. We first identified PrP(C) in association with the lipid raft components Fyn, flotillin-2, GM1 and GM3 in MVs from plasma of healthy human donors. Similar findings were found in MVs from cell culture supernatants of murine neuronal cells. Furthermore we demonstrated that PrP(Sc) is released from infected murine neuronal cells in association with plasma membrane-derived MVs and that PrP(Sc)-bearing MVs are infectious both in vitro and in vivo. The data suggest that MVs may contribute both to the intercellular mechanism(s) of PrP(C) diffusion and signaling as well as to the process of prion spread and neuroinvasion.

| S-EPMC2659799 | biostudies-literature

Recombinant human prion protein inhibits prion propagation in vitro.

Project description:Prion diseases are associated with the conformational conversion of the cellular prion protein (PrP(C)) into the pathological scrapie isoform (PrP(Sc)) in the brain. Both the in vivo and in vitro conversion of PrP(C) into PrP(Sc) is significantly inhibited by differences in amino acid sequence between the two molecules. Using protein misfolding cyclic amplification (PMCA), we now report that the recombinant full-length human PrP (rHuPrP23-231) (that is unglycosylated and lacks the glycophosphatidylinositol anchor) is a strong inhibitor of human prion propagation. Furthermore, rHuPrP23-231 also inhibits mouse prion propagation in a scrapie-infected mouse cell line. Notably, it binds to PrP(Sc), but not PrP(C), suggesting that the inhibitory effect of recombinant PrP results from blocking the interaction of brain PrP(C) with PrP(Sc). Our findings suggest a new avenue for treating prion diseases, in which a patient's own unglycosylated and anchorless PrP is used to inhibit PrP(Sc) propagation without inducing immune response side effects.

| S-EPMC3793212 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data