Inhibition of Protease-Resistant Prion Protein Accumulation In Vitro by Curcumin

ABSTRACT Inhibition of the accumulation of protease-resistant prion protein (PrP-res) is a prime strategy in the development of potential transmissible spongiform encephalopathy (TSE) therapeutics. Here we show that curcumin (diferoylmethane), a major component of the spice turmeric, potently inhibits PrP-res accumulation in scrapie agent-infected neuroblastoma cells (50% inhibitory concentration, ∼10 nM) and partially inhibits the cell-free conversion of PrP to PrP-res. In vivo studies showed that dietary administration of curcumin had no significant effect on the onset of scrapie in hamsters. Nonetheless, other studies have shown that curcumin is nontoxic and can penetrate the brain, properties that give curcumin advantages over inhibitors previously identified as potential prophylactic and/or therapeutic anti-TSE compounds.

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PrP P102L and Nearby Lysine Mutations Promote Spontaneous In Vitro Formation of Transmissible Prions

Journal of Virology ◽

10.1128/jvi.01276-17 ◽

2017 ◽

Vol 91 (21) ◽

Cited By ~ 6

Author(s):

Allison Kraus ◽

Gregory J. Raymond ◽

Brent Race ◽

Katrina J. Campbell ◽

Andrew G. Hughson ◽

...

Keyword(s):

Prion Protein ◽

Prion Diseases ◽

Transmissible Spongiform Encephalopathy ◽

Clinical Signs ◽

Protein Aggregates ◽

Structural Features ◽

Spongiform Encephalopathy ◽

Specific Sequence

ABSTRACT Accumulation of fibrillar protein aggregates is a hallmark of many diseases. While numerous proteins form fibrils by prion-like seeded polymerization in vitro, only some are transmissible and pathogenic in vivo. To probe the structural features that confer transmissibility to prion protein (PrP) fibrils, we have analyzed synthetic PrP amyloids with or without the human prion disease-associated P102L mutation. The formation of infectious prions from PrP molecules in vitro has required cofactors and/or unphysiological denaturing conditions. Here, we demonstrate that, under physiologically compatible conditions without cofactors, the P102L mutation in recombinant hamster PrP promoted prion formation when seeded by minute amounts of scrapie prions in vitro. Surprisingly, combination of the P102L mutation with charge-neutralizing substitutions of four nearby lysines promoted spontaneous prion formation. When inoculated into hamsters, both of these types of synthetic prions initiated substantial accumulation of prion seeding activity and protease-resistant PrP without transmissible spongiform encephalopathy (TSE) clinical signs or notable glial activation. Our evidence suggests that PrP's centrally located proline and lysine residues act as conformational switches in the in vitro formation of transmissible PrP amyloids. IMPORTANCE Many diseases involve the damaging accumulation of specific misfolded proteins in thread-like aggregates. These threads (fibrils) are capable of growing on the ends by seeding the refolding and incorporation of the normal form of the given protein. In many cases such aggregates can be infectious and propagate like prions when transmitted from one individual host to another. Some transmitted aggregates can cause fatal disease, as with human iatrogenic prion diseases, while other aggregates appear to be relatively innocuous. The factors that distinguish infectious and pathogenic protein aggregates from more innocuous ones are poorly understood. Here we have compared the combined effects of prion seeding and mutations of prion protein (PrP) on the structure and transmission properties of synthetic PrP aggregates. Our results highlight the influence of specific sequence features in the normally unstructured region of PrP that influence the infectious and neuropathogenic properties of PrP-derived aggregates.

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Evaluation of Quinacrine Treatment for Prion Diseases

Journal of Virology ◽

10.1128/jvi.77.15.8462-8469.2003 ◽

2003 ◽

Vol 77 (15) ◽

pp. 8462-8469 ◽

Cited By ~ 145

Author(s):

A. Barret ◽

F. Tagliavini ◽

G. Forloni ◽

C. Bate ◽

M. Salmona ◽

...

Keyword(s):

Prion Protein ◽

De Novo ◽

Neuroblastoma Cells ◽

Animal Origin ◽

Detectable Effect ◽

Spongiform Encephalopathy ◽

Protease Resistance ◽

New Variant

ABSTRACT Based on in vitro observations in scrapie-infected neuroblastoma cells, quinacrine has recently been proposed as a treatment for Creutzfeldt-Jakob disease (CJD), including a new variant CJD which is linked to contamination of food by the bovine spongiform encephalopathy (BSE) agent. The present study investigated possible mechanisms of action of quinacrine on prions. The ability of quinacrine to interact with and to reduce the protease resistance of PrP peptide aggregates and PrPres of human and animal origin were analyzed, together with its ability to inhibit the in vitro conversion of the normal prion protein (PrPc) to the abnormal form (PrPres). Furthermore, the efficiencies of quinacrine and chlorpromazine, another tricyclic compound, were examined in different in vitro models and in an experimental murine model of BSE. Quinacrine efficiently hampered de novo generation of fibrillogenic prion protein and PrPres accumulation in ScN2a cells. However, it was unable to affect the protease resistance of preexisting PrP fibrils and PrPres from brain homogenates, and a “curing” effect was obtained in ScGT1 cells only after lengthy treatment. In vivo, no detectable effect was observed in the animal model used, consistent with other recent studies and preliminary observations in humans. Despite its ability to cross the blood-brain barrier, the use of quinacrine for the treatment of CJD is questionable, at least as a monotherapy. The multistep experimental approach employed here could be used to test new therapeutic regimes before their use in human trials.

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Characterization and polyanion-binding properties of purified recombinant prion protein

Biochemical Journal ◽

10.1042/bj3420605 ◽

1999 ◽

Vol 342 (3) ◽

pp. 605-613 ◽

Cited By ~ 20

Author(s):

Debbie B. BRIMACOMBE ◽

Alan D. BENNETT ◽

Fred S. WUSTEMAN ◽

Andrew C. GILL ◽

Janine C. DANN ◽

...

Keyword(s):

Prion Protein ◽

Mammalian Cells ◽

Metal Ion ◽

Transmissible Spongiform Encephalopathy ◽

Spongiform Encephalopathy ◽

Divalent Metal Ions ◽

Dissociation Kinetics ◽

Recombinant Prion Protein

Certain polysulphated polyanions have been shown to have prophylactic effects on the progression of transmissible spongiform encephalopathy disease, presumably because they bind to prion protein (PrP). Until now, the difficulty of obtaining large quantities of native PrP has precluded detailed studies of these interactions. We have over-expressed murine recombinant PrP (recPrP), lacking its glycophosphoinositol membrane anchor, in modified mammalian cells. Milligram quantities of secreted, soluble and partially glycosylated protein were purified under non-denaturing conditions and the identities of mature-length aglycosyl recPrP and two cleavage fragments were determined by electrospray MS. Binding was assessed by surface plasmon resonance techniques using both direct and competitive ligand-binding approaches. recPrP binding to immobilized polyanions was enhanced by divalent metal ions. Polyanion binding was strong and showed complex association and dissociation kinetics that were consistent with ligand-directed recPrP aggregation. The differences in the binding strengths of recPrP to pentosan polysulphate and to other sulphated polyanions were found to parallel their in vivo anti-scrapie and in vitro anti-scrapie-specific PrP formation potencies. When recPrP was immobilized by capture on metal-ion chelates it was found, contrary to expectation, that the addition of polyanions promoted the dissociation of the protein.

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Electromagnetic field in Alzheimer’s disease: a literature review of recent preclinical and clinical studies

Current Alzheimer Research ◽

10.2174/1567205017666201130085853 ◽

2020 ◽

Vol 17 ◽

Author(s):

Reem Habib Mohamad Ali Ahmad ◽

Marc Fakhoury ◽

Nada Lawand

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Neurodegenerative Disorder ◽

In Vivo Studies ◽

Key Factors ◽

Potential Benefits ◽

Preclinical And Clinical Studies ◽

The Brain

: Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the progressive loss of neurons leading to cognitive and memory decay. The main signs of AD include the irregular extracellular accumulation of amyloidbeta (Aβ) protein in the brain and the hyper-phosphorylation of tau protein inside neurons. Changes in Aβ expression or aggregation are considered key factors in the pathophysiology of sporadic and early-onset AD and correlate with the cognitive decline seen in patients with AD. Despite decades of research, current approaches in the treatment of AD are only symptomatic in nature and are not effective in slowing or reversing the course of the disease. Encouragingly, recent evidence revealed that exposure to electromagnetic fields (EMF) can delay the development of AD and improve memory. This review paper discusses findings from in vitro and in vivo studies that investigate the link between EMF and AD at the cellular and behavioural level, and highlights the potential benefits of EMF as an innovative approach for the treatment of AD.

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Development of an LDL Receptor-Targeted Peptide Susceptible to Facilitate the Brain Access of Diagnostic or Therapeutic Agents

Biology ◽

10.3390/biology9070161 ◽

2020 ◽

Vol 9 (7) ◽

pp. 161

Author(s):

Séverine André ◽

Lionel Larbanoix ◽

Sébastien Verteneuil ◽

Dimitri Stanicki ◽

Denis Nonclercq ◽

...

Keyword(s):

Ldl Receptor ◽

Density Lipoprotein ◽

Therapeutic Agents ◽

In Vivo Studies ◽

Phage Display Technology ◽

Brain Penetration ◽

Wide Range ◽

The Brain

Blood-brain barrier (BBB) crossing and brain penetration are really challenging for the delivery of therapeutic agents and imaging probes. The development of new crossing strategies is needed, and a wide range of approaches (invasive or not) have been proposed so far. The receptor-mediated transcytosis is an attractive mechanism, allowing the non-invasive penetration of the BBB. Among available targets, the low-density lipoprotein (LDL) receptor (LDLR) shows favorable characteristics mainly because of the lysosome-bypassed pathway of LDL delivery to the brain, allowing an intact discharge of the carried ligand to the brain targets. The phage display technology was employed to identify a dodecapeptide targeted to the extracellular domain of LDLR (ED-LDLR). This peptide was able to bind the ED-LDLR in the presence of natural ligands and dissociated at acidic pH and in the absence of calcium, in a similar manner as the LDL. In vitro, our peptide was endocytosed by endothelial cells through the caveolae-dependent pathway, proper to the LDLR route in BBB, suggesting the prevention of its lysosomal degradation. The in vivo studies performed by magnetic resonance imaging and fluorescent lifetime imaging suggested the brain penetration of this ED-LDLR-targeted peptide.

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Boosting GSH Using the Co-Drug Approach: I-152, a Conjugate of N-acetyl-cysteine and β-mercaptoethylamine

Nutrients ◽

10.3390/nu11061291 ◽

2019 ◽

Vol 11 (6) ◽

pp. 1291 ◽

Cited By ~ 5

Author(s):

Rita Crinelli ◽

Carolina Zara ◽

Michaël Smietana ◽

Michele Retini ◽

Mauro Magnani ◽

...

Keyword(s):

Cell Cultures ◽

In Vivo Studies ◽

In Vivo Metabolism ◽

Pharmacokinetic Properties ◽

Immunomodulatory Properties ◽

Acetyl Cysteine ◽

High Doses ◽

The Brain

Glutathione (GSH) has poor pharmacokinetic properties; thus, several derivatives and biosynthetic precursors have been proposed as GSH-boosting drugs. I-152 is a conjugate of N-acetyl-cysteine (NAC) and S-acetyl-β-mercaptoethylamine (SMEA) designed to release the parent drugs (i.e., NAC and β-mercaptoethylamine or cysteamine, MEA). NAC is a precursor of L-cysteine, while MEA is an aminothiol able to increase GSH content; thus, I-152 represents the very first attempt to combine two pro-GSH molecules. In this review, the in-vitro and in-vivo metabolism, pro-GSH activity and antiviral and immunomodulatory properties of I-152 are discussed. Under physiological GSH conditions, low I-152 doses increase cellular GSH content; by contrast, high doses cause GSH depletion but yield a high content of NAC, MEA and I-152, which can be used to resynthesize GSH. Preliminary in-vivo studies suggest that the molecule reaches mouse organs, including the brain, where its metabolites, NAC and MEA, are detected. In cell cultures, I-152 replenishes experimentally depleted GSH levels. Moreover, administration of I-152 to C57BL/6 mice infected with the retroviral complex LP-BM5 is effective in contrasting virus-induced GSH depletion, exerting at the same time antiviral and immunomodulatory functions. I-152 acts as a pro-GSH agent; however, GSH derivatives and NAC cannot completely replicate its effects. The co-delivery of different thiol species may lead to unpredictable outcomes, which warrant further investigation.

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Factors affecting interactions between prion protein isoforms

Biochemical Society Transactions ◽

10.1042/bst0300565 ◽

2002 ◽

Vol 30 (4) ◽

pp. 565-569 ◽

Cited By ~ 8

Author(s):

B. Caughey ◽

G. S. Baron

Keyword(s):

Prion Protein ◽

Recipient Cell ◽

Transmissible Spongiform Encephalopathy ◽

Heparan Sulphate ◽

Protein Isoforms ◽

Spongiform Encephalopathy ◽

Factors Affecting ◽

C Terminus ◽

Low Concentrations

Interactions between normal, protease-sensitive prion protein (PrP-sen or PrPc) and its protease-resistant isoform (PrP-res or PrPsc) are critical in transmissible spongiform encephalopathy (TSE) diseases. To investigate the propagation of PrP-res between cells we tested whether PrP-res in scrapie brain microsomes can induce the conversion of PrP-sen to PrP-res if the PrP-sen is bound to uninfected raft membranes. Surprisingly, no conversion was observed unless the microsomal and raft membranes were fused or PrP-sen was released from raft membranes. These results suggest that the propagation of infection between cells requires transfer of PrP-res into the membranes of the recipient cell. To assess potential cofactors in PrP conversion, we used cell-free PrP conversion assays to show that heparan sulphate can stimulate PrP-res formation, supporting the idea that endogenous sulphated glycosaminoglycans can act as important cofactors or modulators of PrP-res formation in vivo. In an effort to develop therapeutics, the antimalarial drug quinacrine was identified as an inhibitor of PrP-res formation in scrapie-infected cell cultures. Confirmation of the latter result by others has led to the initiation of human clinical trials as a treatment for Creutzfeldt-Jakob disease. PrP-res formation can also be inhibited using a variety of other types of small molecule, specific synthetic PrP peptides, and an antiserum directed at the C-terminus of PrP-sen. The latter results help to localize the sites of interaction between PrP-sen and PrP-res. Disruption of those interactions with antibodies or peptidomimetic drugs may be an attractive therapeutic strategy. The likelihood that PrP-res inhibitors can rid TSE-infected tissues of PrP-res would presumably be enhanced if PrP-res formation were reversible. However, our attempts to measure dissociation of PrP-sen from PrP-res have failed under non-denaturing conditions. Finally, we have attempted to induce the spontaneous conversion of PrP-sen into PrP-res using low concentrations of detergents. A conformational conversion from α-helical monomers into high-β-sheet aggregates and fibrils was induced by low concentrations of the detergent sarkosyl; however, the aggregates had neither infectivity nor the characteristic protease-resistance of PrP-res.

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Stretchable multichannel antennas in soft wireless optoelectronic implants for optogenetics

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1611769113 ◽

2016 ◽

Vol 113 (50) ◽

pp. E8169-E8177 ◽

Cited By ~ 59

Author(s):

Sung Il Park ◽

Gunchul Shin ◽

Jordan G. McCall ◽

Ream Al-Hasani ◽

Aaron Norris ◽

...

Keyword(s):

Radio Frequency ◽

Antenna Arrays ◽

Capacitive Coupling ◽

Radio Frequency Power ◽

In Vivo Studies ◽

Active Motion ◽

The Brain ◽

Frequency Power

Optogenetic methods to modulate cells and signaling pathways via targeted expression and activation of light-sensitive proteins have greatly accelerated the process of mapping complex neural circuits and defining their roles in physiological and pathological contexts. Recently demonstrated technologies based on injectable, microscale inorganic light-emitting diodes (μ-ILEDs) with wireless control and power delivery strategies offer important functionality in such experiments, by eliminating the external tethers associated with traditional fiber optic approaches. Existing wireless μ-ILED embodiments allow, however, illumination only at a single targeted region of the brain with a single optical wavelength and over spatial ranges of operation that are constrained by the radio frequency power transmission hardware. Here we report stretchable, multiresonance antennas and battery-free schemes for multichannel wireless operation of independently addressable, multicolor μ-ILEDs with fully implantable, miniaturized platforms. This advance, as demonstrated through in vitro and in vivo studies using thin, mechanically soft systems that separately control as many as three different μ-ILEDs, relies on specially designed stretchable antennas in which parallel capacitive coupling circuits yield several independent, well-separated operating frequencies, as verified through experimental and modeling results. When used in combination with active motion-tracking antenna arrays, these devices enable multichannel optogenetic research on complex behavioral responses in groups of animals over large areas at low levels of radio frequency power (<1 W). Studies of the regions of the brain that are involved in sleep arousal (locus coeruleus) and preference/aversion (nucleus accumbens) demonstrate the unique capabilities of these technologies.

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Inhibition of Protease-Resistant Prion Protein Formation in a Transformed Deer Cell Line Infected with Chronic Wasting Disease

Journal of Virology ◽

10.1128/jvi.80.2.596-604.2006 ◽

2006 ◽

Vol 80 (2) ◽

pp. 596-604 ◽

Cited By ~ 48

Author(s):

Gregory J. Raymond ◽

Emily A. Olsen ◽

Kil Sun Lee ◽

Lynne D. Raymond ◽

P. Kruger Bryant ◽

...

Keyword(s):

Cell Line ◽

Prion Protein ◽

Chronic Wasting Disease ◽

Transmissible Spongiform Encephalopathy ◽

Mule Deer ◽

Simian Virus 40 ◽

Spongiform Encephalopathy ◽

Wasting Disease ◽

Neuronal Marker

ABSTRACT Chronic wasting disease (CWD) is an emerging transmissible spongiform encephalopathy (prion disease) of North American cervids, i.e., mule deer, white-tailed deer, and elk (wapiti). To facilitate in vitro studies of CWD, we have developed a transformed deer cell line that is persistently infected with CWD. Primary cultures derived from uninfected mule deer brain tissue were transformed by transfection with a plasmid containing the simian virus 40 genome. A transformed cell line (MDB) was exposed to microsomes prepared from the brainstem of a CWD-affected mule deer. CWD-associated, protease-resistant prion protein (PrPCWD) was used as an indicator of CWD infection. Although no PrPCWD was detected in any of these cultures after two passes, dilution cloning of cells yielded one PrPCWD-positive clone out of 51. This clone, designated MDBCWD, has maintained stable PrPCWD production through 32 serial passes thus far. A second round of dilution cloning yielded 20 PrPCWD-positive subclones out of 30, one of which was designated MDBCWD2. The MDBCWD2 cell line was positive for fibronectin and negative for microtubule-associated protein 2 (a neuronal marker) and glial fibrillary acidic protein (an activated astrocyte marker), consistent with derivation from brain fibroblasts (e.g., meningeal fibroblasts). Two inhibitors of rodent scrapie protease-resistant PrP accumulation, pentosan polysulfate and a porphyrin compound, indium (III) meso-tetra(4-sulfonatophenyl)porphine chloride, potently blocked PrPCWD accumulation in MDBCWD cells. This demonstrates the utility of these cells in a rapid in vitro screening assay for PrPCWD inhibitors and suggests that these compounds have potential to be active against CWD in vivo.

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