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1.
Emerg Infect Dis ; 30(6): 1193-1202, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38781931

RESUMO

Chronic wasting disease (CWD) is a cervid prion disease with unknown zoonotic potential that might pose a risk to humans who are exposed. To assess the potential of CWD to infect human neural tissue, we used human cerebral organoids with 2 different prion genotypes, 1 of which has previously been associated with susceptibility to zoonotic prion disease. We exposed organoids from both genotypes to high concentrations of CWD inocula from 3 different sources for 7 days, then screened for infection periodically for up to 180 days. No de novo CWD propagation or deposition of protease-resistant forms of human prions was evident in CWD-exposed organoids. Some persistence of the original inoculum was detected, which was equivalent in prion gene knockout organoids and thus not attributable to human prion propagation. Overall, the unsuccessful propagation of CWD in cerebral organoids supports a strong species barrier to transmission of CWD prions to humans.


Assuntos
Organoides , Príons , Doença de Emaciação Crônica , Doença de Emaciação Crônica/transmissão , Humanos , Príons/metabolismo , Animais , Encéfalo/patologia , Genótipo
2.
Vet Res ; 55(1): 62, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750594

RESUMO

The first case of CWD in a Norwegian red deer was detected by a routine ELISA test and confirmed by western blotting and immunohistochemistry in the brain stem of the animal. Two different western blotting tests were conducted independently in two different laboratories, showing that the red deer glycoprofile was different from the Norwegian CWD reindeer and CWD moose and from North American CWD. The isolate showed nevertheless features similar to the classical BSE (BSE-C) strain. Furthermore, BSE-C could not be excluded based on the PrPSc immunohistochemistry staining in the brainstem and the absence of detectable PrPSc in the lymphoid tissues. Because of the known ability of BSE-C to cross species barriers as well as its zoonotic potential, the CWD red deer isolate was submitted to the EURL Strain Typing Expert Group (STEG) as a BSE-C suspect for further investigation. In addition, different strain typing in vivo and in vitro strategies aiming at identifying the BSE-C strain in the red deer isolate were performed independently in three research groups and BSE-C was not found in it. These results suggest that the Norwegian CWD red deer case was infected with a previously unknown CWD type and further investigation is needed to determine the characteristics of this potential new CWD strain.


Assuntos
Cervos , Encefalopatia Espongiforme Bovina , Doença de Emaciação Crônica , Animais , Noruega , Western Blotting/veterinária , Ensaio de Imunoadsorção Enzimática/veterinária , Príons/metabolismo , Bovinos , Imuno-Histoquímica/veterinária , Proteínas PrPSc/metabolismo
4.
Cells ; 13(10)2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38786054

RESUMO

Prion diseases are rare and neurodegenerative diseases that are characterized by the misfolding and infectious spread of the prion protein in the brain, causing progressive and irreversible neuronal loss and associated clinical and behavioral manifestations in humans and animals, ultimately leading to death. The brain has a complex network of neurons and glial cells whose crosstalk is critical for function and homeostasis. Although it is established that prion infection of neurons is necessary for clinical disease to occur, debate remains in the field as to the role played by glial cells, namely astrocytes and microglia, and whether these cells are beneficial to the host or further accelerate disease. Here, we review the current literature assessing the complex morphologies of astrocytes and microglia, and the crosstalk between these two cell types, in the prion-infected brain.


Assuntos
Neuroglia , Doenças Priônicas , Humanos , Doenças Priônicas/patologia , Doenças Priônicas/metabolismo , Animais , Neuroglia/patologia , Neuroglia/metabolismo , Astrócitos/patologia , Astrócitos/metabolismo , Encéfalo/patologia , Encéfalo/metabolismo , Neurobiologia , Microglia/patologia , Microglia/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Neuropatologia , Príons/metabolismo
5.
Viruses ; 16(5)2024 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-38793671

RESUMO

The key postulate of the prion paradigm is that some proteins can take on unconventional conformations and pass these conformations to newly synthesized protein molecules with the same primary structure [...].


Assuntos
Príons , Príons/metabolismo , Príons/química , Animais , Humanos , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Doenças Priônicas/metabolismo , Conformação Proteica , Mamíferos/metabolismo
6.
Prion ; 18(1): 72-86, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38676289

RESUMO

Infectious prions are resistant to degradation and remain infectious in the environment for several years. Chronic wasting disease (CWD) has been detected in cervids inhabiting North America, the Nordic countries, and South Korea. CWD-prion spread is partially attributed to carcass transport and disposal. We employed a forensic approach to investigate an illegal carcass dump site connected with a CWD-positive herd. We integrated anatomic, genetic, and prion amplification methods to discover CWD-positive remains from six white-tailed deer (Odocoileus virginianus) and, using microsatellite markers, confirmed a portion originated from the CWD-infected herd. This approach provides a foundation for future studies of carcass prion transmission risk.


Assuntos
Cervos , Príons , Doença de Emaciação Crônica , Animais , Doença de Emaciação Crônica/transmissão , Príons/genética , Príons/metabolismo , Repetições de Microssatélites/genética
7.
Mov Disord ; 39(5): 766-767, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38627965

RESUMO

Sinus infection of Saccharomyces cerevisiae accelerates the aggregation of α-synuclein (α-syn) in A53T mice, which was caused by prion protein Sup35. Sup35 promotes α-syn aggregation in vitro and in vivo and leads to Parkinson's disease (PD)-like motor impairment in wildtype mice, suggesting that the yeast Sup35 triggers α-syn pathology in PD.


Assuntos
Doença de Parkinson , Fatores de Terminação de Peptídeos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , alfa-Sinucleína , alfa-Sinucleína/metabolismo , alfa-Sinucleína/genética , Animais , Camundongos , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Fatores de Terminação de Peptídeos/metabolismo , Fatores de Terminação de Peptídeos/genética , Saccharomyces cerevisiae/metabolismo , Camundongos Transgênicos , Humanos , Modelos Animais de Doenças , Príons/metabolismo , Príons/genética
8.
Prion ; 18(1): 68-71, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38651736

RESUMO

The history of human prion diseases began with the original description, by Hans Gerhard Creutzfeldt and by Alfons Maria Jakob, of patients with a severe brain disease that included speech abnormalities, confusion, and myoclonus, in a disease that was then named Creutzfeldt Jakob disease (CJD). Later, in Papua New Guinea, a disease characterized by trembling was identified, and given the name "Kuru". Neuropathological examination of the brains from CJD and Kuru patients, and of brains of sheep with scrapie disease revealed significant similarities and suggested a possible common mode of infection that, at the time, was thought to derive from an unknown virus that caused slow infections. John Stanley Griffith hypothesized that the agent causing these diseases was "probably a protein without nucleic acid" and, in 1982, Stanley Prusiner reported the identification of a proteinaceous infectious particle (coining the term prion) that was resistant to inactivation methods that were at the time standard for nucleic acids, and identified PrP as the major protein component of the infectious agent in scrapie and in Creutzfeldt-Jakob disease, classifying this also as a prion disease. Interestingly, the prion concept had been previously expanded to yeast proteins capable of replicating their conformation, seeding their own aggregation and transmitting phenotypic information. The prion concept has been more recently expanded to refer to misfolded proteins that are capable of converting a normal form of a protein into an abnormal form. The quest to understand and treat prion diseases has united a specific research community around the topic, and regular meetings (Prion Meetings) have taken place over the years to enable discussions, train junior researchers, and inspire research in the field.


Assuntos
Doenças Priônicas , Príons , Humanos , Doenças Priônicas/patologia , Doenças Priônicas/metabolismo , Animais , Príons/metabolismo , Síndrome de Creutzfeldt-Jakob/patologia , Síndrome de Creutzfeldt-Jakob/metabolismo , Kuru/patologia
9.
Viruses ; 16(4)2024 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-38675927

RESUMO

Located 50 miles west of Fort Collins, Colorado, Colorado State University's Mountain Campus in Pingree Park hosted the 23rd annual Rocky Mountain Virology Association meeting in 2023 with 116 participants. The 3-day event at the end of September consisted of 28 talks and 43 posters that covered the topics of viral evolution and surveillance, developments in prion research, arboviruses and vector biology, host-virus interactions, and viral immunity and vaccines. This year's Randall Jay Cohrs keynote presentation covered the topic of One Health and emerging coronaviruses. This timely discussion covered the importance of global disease surveillance, international collaboration, and trans-disciplinary research teams to prevent and control future pandemics. Peak fall colors flanked the campus and glowed along the multiple mountain peaks, allowing for pristine views while discussing science and networking, or engaging in mountain activities like fly fishing and hiking. On behalf of the Rocky Mountain Virology Association, this report summarizes select presentations from the 23rd annual meeting.


Assuntos
Virologia , Humanos , Colorado , Animais , Viroses/virologia , Vírus/genética , Vírus/classificação , Príons , Arbovírus , Saúde Única
10.
J Mol Biol ; 436(11): 168576, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38641239

RESUMO

Prions, the misfolding form of prion proteins, are contagious proteinaceous macromolecules. Recent studies have shown that infectious prion fibrils formed in the brain and non-infectious fibrils formed from recombinant prion protein in a partially denaturing condition have distinct structures. The amyloid core of the in vitro-prepared non-infectious fibrils starts at about residue 160, while that of infectious prion fibrils formed in the brain involves a longer sequence (residues ∼90-230) of structural conversion. The C-terminal truncated prion protein PrP(23-144) can form infectious fibrils under certain conditions and cause disease in animals. In this study, we used cryogenic electron microscopy (cryo-EM) to resolve the structure of hamster sHaPrP(23-144) fibrils prepared at pH 3.7. This 2.88 Å cryo-EM structure has an amyloid core covering residues 94-144. It comprises two protofilaments, each containing five ß-strands arranged as a long hairpin plus an N-terminal ß-strand. This N-terminal ß-strand resides in a positively charged cluster region (named PCC2; sequence 96-111), which interacts with the turn region of the opposite protofilaments' hairpin to stabilize the fibril structure. Interestingly, this sHaPrP(23-144) fibril structure differs from a recently reported structure formed by the human or mouse counterpart at pH 6.5. Moreover, sHaPrP(23-144) fibrils have many structural features in common with infectious prions. Whether this structure is infectious remains to be determined. More importantly, the sHaPrP(23-144) structure is different from the sHaPrP(108-144) fibrils prepared in the same fibrillization buffer, indicating that the N-terminal disordered region, possibly the positively charged cluster, influences the misfolding pathway of the prion protein.


Assuntos
Amiloide , Microscopia Crioeletrônica , Proteínas Priônicas , Dobramento de Proteína , Microscopia Crioeletrônica/métodos , Animais , Amiloide/química , Amiloide/metabolismo , Amiloide/ultraestrutura , Cricetinae , Proteínas Priônicas/química , Proteínas Priônicas/metabolismo , Proteínas Priônicas/genética , Modelos Moleculares , Príons/química , Príons/metabolismo , Príons/ultraestrutura , Conformação Proteica
11.
PLoS Pathog ; 20(4): e1012175, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38640117

RESUMO

Prions or prion-like aggregates such as those composed of PrP, α-synuclein, and tau are key features of proteinopathies such as prion, Parkinson's and Alzheimer's diseases, respectively. Their presence on solid surfaces may be biohazardous under some circumstances. PrP prions bound to solids are detectable by ultrasensitive real-time quaking-induced conversion (RT-QuIC) assays if the solids can be immersed in assay wells or the prions transferred to pads. Here we show that prion-like seeds can remain detectable on steel wires for at least a year, or even after enzymatic cleaning and sterilization. We also show that contamination of larger objects with pathological seeds of α-synuclein, tau, and PrP can be detected by simply assaying a sampling medium that has been transiently applied to the surface. Human α-synuclein seeds in dementia with Lewy bodies brain tissue were detected by α-synuclein RT-QuIC after drying of tissue dilutions with concentrations as low as 10-6 onto stainless steel. Tau RT-QuIC detected tau seeding activity on steel exposed to Alzheimer's disease brain tissue diluted as much as a billion fold. Prion RT-QuIC assays detected seeding activity on plates exposed to brain dilutions as extreme as 10-5-10-8 from prion-affected humans, sheep, cattle and cervids. Sampling medium collected from surgical instruments used in necropsies of sporadic Creutzfeldt-Jakob disease-infected transgenic mice was positive down to 10-6 dilution. Sensitivity for prion detection was not sacrificed by omitting the recombinant PrP substrate from the sampling medium during its application to a surface and subsequent storage as long as the substrate was added prior to performing the assay reaction. Our findings demonstrate practical prototypic surface RT-QuIC protocols for the highly sensitive detection of pathologic seeds of α-synuclein, tau, and PrP on solid objects.


Assuntos
Proteínas Priônicas , alfa-Sinucleína , Proteínas tau , Proteínas tau/metabolismo , alfa-Sinucleína/metabolismo , alfa-Sinucleína/análise , Humanos , Proteínas Priônicas/metabolismo , Animais , Camundongos , Encéfalo/metabolismo , Encéfalo/patologia , Príons/metabolismo , Doença por Corpos de Lewy/metabolismo
12.
J Neurosci ; 44(20)2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38589228

RESUMO

Protein misfolding, aggregation, and spread through the brain are primary drivers of neurodegenerative disease pathogenesis. Phagocytic glia are responsible for regulating the load of pathological proteins in the brain, but emerging evidence suggests that glia may also act as vectors for aggregate spread. Accumulation of protein aggregates could compromise the ability of glia to eliminate toxic materials from the brain by disrupting efficient degradation in the phagolysosomal system. A better understanding of phagocytic glial cell deficiencies in the disease state could help to identify novel therapeutic targets for multiple neurological disorders. Here, we report that mutant huntingtin (mHTT) aggregates impair glial responsiveness to injury and capacity to degrade neuronal debris in male and female adult Drosophila expressing the gene that causes Huntington's disease (HD). mHTT aggregate formation in neurons impairs engulfment and clearance of injured axons and causes accumulation of phagolysosomes in glia. Neuronal mHTT expression induces upregulation of key innate immunity and phagocytic genes, some of which were found to regulate mHTT aggregate burden in the brain. A forward genetic screen revealed Rab10 as a novel component of Draper-dependent phagocytosis that regulates mHTT aggregate transmission from neurons to glia. These data suggest that glial phagocytic defects enable engulfed mHTT aggregates to evade lysosomal degradation and acquire prion-like characteristics. Together, our findings uncover new mechanisms that enhance our understanding of the beneficial and harmful effects of phagocytic glia in HD and other neurodegenerative diseases.


Assuntos
Modelos Animais de Doenças , Proteínas de Drosophila , Drosophila , Proteína Huntingtina , Doença de Huntington , Neuroglia , Animais , Doença de Huntington/metabolismo , Doença de Huntington/patologia , Doença de Huntington/genética , Neuroglia/metabolismo , Neuroglia/patologia , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Feminino , Masculino , Fagocitose/fisiologia , Lisossomos/metabolismo , Fagossomos/metabolismo , Animais Geneticamente Modificados , Príons/metabolismo , Príons/genética , Neurônios/metabolismo
14.
PLoS Pathog ; 20(4): e1012087, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38557815

RESUMO

Prion diseases uniquely manifest in three distinct forms: inherited, sporadic, and infectious. Wild-type prions are responsible for the sporadic and infectious versions, while mutant prions cause inherited variants like fatal familial insomnia (FFI) and familial Creutzfeldt-Jakob disease (fCJD). Although some drugs can prolong prion incubation times up to four-fold in rodent models of infectious prion diseases, no effective treatments for FFI and fCJD have been found. In this study, we evaluated the efficacy of various anti-prion drugs on newly-developed knock-in mouse models for FFI and fCJD. These models express bank vole prion protein (PrP) with the pathogenic D178N and E200K mutations. We applied various drug regimens known to be highly effective against wild-type prions in vivo as well as a brain-penetrant compound that inhibits mutant PrPSc propagation in vitro. None of the regimens tested (Anle138b, IND24, Anle138b + IND24, cellulose ether, and PSCMA) significantly extended disease-free survival or prevented mutant PrPSc accumulation in either knock-in mouse model, despite their ability to induce strain adaptation of mutant prions. Our results show that anti-prion drugs originally developed to treat infectious prion diseases do not necessarily work for inherited prion diseases, and that the recombinant sPMCA is not a reliable platform for identifying compounds that target mutant prions. This work underscores the need to develop therapies and validate screening assays specifically for mutant prions, as well as anti-prion strategies that are not strain-dependent.


Assuntos
Síndrome de Creutzfeldt-Jakob , Doenças Priônicas , Príons , Animais , Camundongos , Príons/metabolismo , Doenças Priônicas/tratamento farmacológico , Doenças Priônicas/genética , Doenças Priônicas/metabolismo , Síndrome de Creutzfeldt-Jakob/tratamento farmacológico , Síndrome de Creutzfeldt-Jakob/genética , Síndrome de Creutzfeldt-Jakob/metabolismo , Proteínas Priônicas/genética , Proteínas Priônicas/metabolismo , Encéfalo/patologia , Arvicolinae/metabolismo
15.
Life Sci Alliance ; 7(6)2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38570188

RESUMO

Mistargeting of secretory proteins in the cytosol can trigger their aggregation and subsequent proteostasis decline. We have identified a VCP/p97-dependent pathway that directs non-ER-imported prion protein (PrP) into the nucleus to prevent the formation of toxic aggregates in the cytosol. Upon impaired translocation into the ER, PrP interacts with VCP/p97, which facilitates nuclear import mediated by importin-ß. Notably, the cytosolic interaction of PrP with VCP/p97 and its nuclear import are independent of ubiquitination. In vitro experiments revealed that VCP/p97 binds non-ubiquitinated PrP and prevents its aggregation. Inhibiting binding of PrP to VCP/p97, or transient proteotoxic stress, promotes the formation of self-perpetuating and partially proteinase resistant PrP aggregates in the cytosol, which compromised cellular proteostasis and disrupted further nuclear targeting of PrP. In the nucleus, RNAs keep PrP in a soluble and non-toxic conformation. Our study revealed a novel ubiquitin-independent role of VCP/p97 in the nuclear targeting of non-imported secretory proteins and highlights the impact of the chemical milieu in triggering protein misfolding.


Assuntos
Proteínas Priônicas , Príons , Proteínas Priônicas/metabolismo , Proteína com Valosina/metabolismo , Adenosina Trifosfatases/metabolismo , Proteostase , Ubiquitina/metabolismo , Príons/metabolismo
16.
BMC Vet Res ; 20(1): 152, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38654224

RESUMO

BACKGROUND: Chronic wasting disease (CWD) is a prion disease of captive and free-ranging cervids. Currently, a definitive diagnosis of CWD relies on immunohistochemistry detection of PrPSc in the obex and retropharyngeal lymph node (RPLN) of the affected cervids. For high-throughput screening of CWD in wild cervids, RPLN samples are tested by ELISA followed by IHC confirmation of positive results. Recently, real-time quacking-induced conversion (RT-QuIC) has been used to detect CWD positivity in various types of samples. To develop a blood RT-QuIC assay suitable for CWD diagnosis, this study evaluated the assay sensitivity and specificity with and without ASR1-based preanalytical enrichment and NaI as the main ionic component in assay buffer. RESULTS: A total of 23 platelet samples derived from CWD-positive deer (ELISA + /IHC +) and 30 platelet samples from CWD-negative (ELISA-) deer were tested. The diagnostic sensitivity was 43.48% (NaCl), 65.22% (NaI), 60.87% (NaCl-ASR1) or 82.61% (NaI-ASR1). The diagnostic specificity was 96.67% (NaCl), 100% (NaI), 100% (NaCl-ASR1), or 96.67% (NaI-ASR1). The probability of detecting CWD prion in platelet samples derived from CWD-positive deer was 0.924 (95% CRI: 0.714, 0.989) under NaI-ASR1 experimental condition and 0.530 (95% CRI: 0.156, 0.890) under NaCl alone condition. The rate of amyloid formation (RFA) was greatest under the NaI-ASR1 condition at 10-2 (0.01491, 95% CRI: 0.00675, 0.03384) and 10-3 (0.00629, 95% CRI: 0.00283, 0.01410) sample dilution levels. CONCLUSIONS: Incorporation of ASR1-based preanalytical enrichment and NaI as the main ionic component significantly improved the sensitivity of CWD RT-QuIC on deer platelet samples. Blood test by the improved RT-QuIC assay may be used for antemortem and postmortem diagnosis of CWD.


Assuntos
Plaquetas , Cervos , Sensibilidade e Especificidade , Doença de Emaciação Crônica , Animais , Cervos/sangue , Doença de Emaciação Crônica/diagnóstico , Doença de Emaciação Crônica/sangue , Plaquetas/química , Ensaio de Imunoadsorção Enzimática/veterinária , Príons/sangue
17.
Prion ; 18(1): 40-53, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38627365

RESUMO

Prion disease is an infectious and fatal neurodegenerative disease. Western blotting (WB)-based identification of proteinase K (PK)-resistant prion protein (PrPres) is considered a definitive diagnosis of prion diseases. In this study, we aimed to detect PrPres using formalin-fixed paraffin-embedded (FFPE) specimens from cases of sporadic Creutzfeldt-Jakob disease (sCJD), Gerstmann-Sträussler-Scheinker disease (GSS), glycosylphosphatidylinositol-anchorless prion disease (GPIALP), and V180I CJD. FFPE samples were prepared after formic acid treatment to inactivate infectivity. After deparaffinization, PK digestion was performed, and the protein was extracted. In sCJD, a pronounced PrPres signal was observed, with antibodies specific for type 1 and type 2 PrPres exhibited a strong or weak signals depending on the case. Histological examination of serial sections revealed that the histological changes were compatible with the biochemical characteristics. In GSS and GPIALP, prion protein core-specific antibodies presented as PrPres bands at 8-9 kDa and smear bands, respectively. However, an antibody specific for the C-terminus presented as smears in GSS, with no PrPres detected in GPIALP. It was difficult to detect PrPres in V180I CJD. Collectively, our findings demonstrate the possibility of detecting PrPres in FFPE and classifying the prion disease types. This approach facilitates histopathological and biochemical evaluation in the same sample and is safe owing to the inactivation of infectivity. Therefore, it may be valuable for the diagnosis and research of prion diseases.


Assuntos
Síndrome de Creutzfeldt-Jakob , Doença de Gerstmann-Straussler-Scheinker , Doenças Neurodegenerativas , Doenças Priônicas , Príons , Humanos , Proteínas Priônicas , Proteínas PrPSc/metabolismo , Inclusão em Parafina , Doenças Priônicas/diagnóstico , Doenças Priônicas/metabolismo , Síndrome de Creutzfeldt-Jakob/patologia , Príons/metabolismo , Doença de Gerstmann-Straussler-Scheinker/metabolismo , Endopeptidase K , Anticorpos , Formaldeído
18.
Proc Natl Acad Sci U S A ; 121(15): e2320456121, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38568974

RESUMO

Prion-like spread of disease-specific tau conformers is a hallmark of all tauopathies. A 19-residue probe peptide containing a P301L mutation and spanning the R2/R3 splice junction of tau folds and stacks into seeding-competent fibrils and induces aggregation of 4R, but not 3R tau. These tau peptide fibrils propagate aggregated intracellular tau over multiple generations, have a high ß-sheet content, a colocalized lipid signal, and adopt a well-defined U-shaped fold found in 4R tauopathy brain-derived fibrils. Fully atomistic replica exchange molecular dynamics (MD) simulations were used to compute the free energy landscapes of the conformational ensemble of the peptide monomers. These identified an aggregation-prohibiting ß-hairpin structure and an aggregation-competent U-fold unique to 4R tauopathy fibrils. Guided by MD simulations, we identified that the N-terminal-flanking residues to PHF6, which slightly vary between 4R and 3R isoforms, modulate seeding. Strikingly, when a single amino acid switch at position 305 replaced the serine of 4R tau with a lysine from the corresponding position in the first repeat of 3R tau, the seeding induced by the 19-residue peptide was markedly reduced. Conversely, a 4R tau mimic with three repeats, prepared by replacing those amino acids in the first repeat with those amino acids uniquely present in the second repeat, recovered aggregation when exposed to the 19-residue peptide. These peptide fibrils function as partial prions to recruit naive 4R tau-ten times the length of the peptide-and serve as a critical template for 4R tauopathy propagation. These results hint at opportunities for tau isoform-specific therapeutic interventions.


Assuntos
Príons , Tauopatias , Humanos , Proteínas tau/metabolismo , Tauopatias/metabolismo , Isoformas de Proteínas/metabolismo , Príons/metabolismo , Peptídeos , Aminoácidos
20.
BMC Neurol ; 24(1): 92, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38468258

RESUMO

BACKGROUND: Human prion diseases (HPDs) are fatal neurodegenerative disorders characterized by abnormal prion proteins (PrPSc). However, the detection of prion seeding activity in patients with high sensitivity remains challenging. Even though real-time quaking-induced conversion (RT-QuIC) assay is suitable for detecting prion seeding activity in a variety of specimens, it shows lower accuracy when whole blood, blood plasma, and blood-contaminated tissue samples are used. In this study, we developed a novel technology for the in vitro amplification of abnormal prion proteins in HPD to the end of enabling their detection with high sensitivity known as the enhanced quaking-induced conversion (eQuIC) assay. METHODS: Three antibodies were used to develop the novel eQUIC method. Thereafter, SD50 seed activity was analyzed using brain tissue samples from patients with prion disease using the conventional RT-QUIC assay and the novel eQUIC assay. In addition, blood samples from six patients with solitary prion disease were analyzed using the novel eQuIC assay. RESULTS: The eQuIC assay, involving the use of three types of human monoclonal antibodies, showed approximately 1000-fold higher sensitivity than the original RT-QuIC assay. However, when this assay was used to analyze blood samples from six patients with sporadic human prion disease, no prion activity was detected. CONCLUSION: The detection of prion seeding activity in blood samples from patients with sporadic prion disease remains challenging. Thus, the development of alternative methods other than RT-QuIC and eQuIC will be necessary for future research.


Assuntos
Síndrome de Creutzfeldt-Jakob , Doenças Priônicas , Príons , Humanos , Príons/metabolismo , Proteínas Priônicas , Doenças Priônicas/diagnóstico , Doenças Priônicas/metabolismo , Encéfalo/metabolismo , Plasma/metabolismo , Síndrome de Creutzfeldt-Jakob/diagnóstico
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