Animals ; PrPSc Proteins ; metabolism ; pathogenicity ; Prion Diseases ; transmission ; Prions ; physiology

Objective: The definite diagnosis of human and animal prion diseases depends on the examination of special pathological changes and/or detection of PrP in the brain tissues of suspected cases. Thus, developing methods to obtain PrP antibody with good specificity and sensitivity is fundamental for prion identification. Methods: We prepared a PrP-specific polyclonal antibody (pAb P54) in a -knockout mouse model immunization with recombinant full-length human PrP protein residues 23-231. Thereafter, we verified that pAb in Western blot, immunohistochemistry (IHC), and immunofluorescent (IFA) assays. Results: Western blot illustrated that the newly prepared pAb P54 could react with recombinant PrP protein, normal brain PrP from healthy rodents and humans, and pathological PrP in the brains of experimental rodents infected with scrapie and humans infected with different types of prion diseases. The electrophoretic patterns of brain PrP and PrP observed after their reaction with pAb P54 were nearly identical to those produced by commercial PrP monoclonal antibodies. Three glycosylated PrP molecules in the brain homogenates were clearly demonstrated in the reactions of these molecules with pAb P54. IHC assay revealed apparent PrP deposits in the GdnCl-treated brain slices of 139A-infected mice and 263K-infected hamsters. IFA tests with pAb P54 also showed clear green signals surrounding blue-stained cell nuclei. Conclusion The newly prepared pAb P54 demonstrated reliable specificity and sensitivity and, thus, may have potential applications not only in studies of prion biology but also in the diagnosis of human and experimental rodent prion diseases.
Animals ; Antibodies ; immunology ; Blotting, Western ; Fluorescent Antibody Technique ; Immunization ; Immunohistochemistry ; Mice ; Mice, Knockout ; PrPC Proteins ; immunology ; PrPSc Proteins ; immunology ; Prion Proteins ; immunology ; Recombinant Proteins ; immunology

OBJECTIVETo expatiate dynamic changes in hamsters infected with scrapie strain 263K, to observe the presence and aggravation of various forms of PrP and PrP(Sc) during incubation period, and to probe primarily the relationship between the onset of clinic manifestations and the presence of different PrP(Sc) forms.

METHODSHamster-adapted scrapie strain 263K was intracerebrally inoculated into hamsters. Different forms of PrP and PrP(Sc) were monitored dynamically by Western blot and immuno-histochemical assays. The presence of scrapie-associated fibril (SAF) was assayed by electron microscopy analysis (EM) and immuno-golden EM.

RESULTSPrP(Sc) was initially detected in the brain tissues of the animals in 20 days post-inoculation by immunohistochemistry and 40 days with Western blot. Quantitative evaluations revealed that the amounts of PrP and PrP(Sc) in brain tissues increased along with the incubation. Several high and low molecular masses of PrP were seen in the brains of the long-life span infected animals. Deglycosylation assays identified that the truncated PrP in the infected brains showed similar glycosylation patterns as the full-length PrP. The presence of short fragments was seemed to relate with the onset of clinical conditions.

CONCLUSIONThese results indicate that infectious agents exist and accumulate in central nerve system prior to the onset of the illness. Various molecular patterns of PrP(Sc) may indwell in brain tissues during the infection.

Animals ; Blotting, Western ; Brain ; metabolism ; ultrastructure ; Cricetinae ; Disease Models, Animal ; Female ; Glycosylation ; Immunohistochemistry ; Mesocricetus ; Microscopy, Electron ; PrP 27-30 Protein ; analysis ; metabolism ; PrPC Proteins ; analysis ; metabolism ; PrPSc Proteins ; analysis ; metabolism ; Scrapie ; metabolism ; pathology

Misfolded isoform of prion protein (PrP), termed scrapie PrP (PrP(Sc)), tends to aggregate into various fibril forms. Previously, we reported various conditions that affect aggregation of recombinant PrP into amyloids. Because amyloidogenesis of PrP is closely associated with transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease in humans, we investigated infectivity of recombinant PrP amyloids generated in vitro. Using cultured cell lines which overexpress cellular PrP of different species, we measured the level of de novo synthesized PrP(Sc) in cells inoculated with recombinant mouse PrP amyloids. While PrP-overexpressing cells were susceptible to mouse-adapted scrapie prions used as the positive control, demonstrating the species barrier effect, infection with amyloids made of truncated recombinant PrP (PrP[89-230]) failed to form and propagate PrP(Sc) even in the cells that express mouse cellular PrP. This suggests that infectivity of PrP amyloids generated in vitro is different from that of natural prions. Recombinant PrP (89-230) amyloids tested in the current study retain no or a minute level, if any, of prion infectivity.
Animals ; Cell Line ; Kidney/*metabolism/*pathology ; Mice ; PrPSc Proteins/*metabolism ; Prion Diseases/*metabolism/*pathology ; Prions/*metabolism ; Rabbits ; Recombinant Proteins/*metabolism ; Up-Regulation

Human genetic prion diseases (gPrDs) are directly associated with mutations and insertions in the PRNP (Prion Protein) gene. We collected and analyzed the data of 218 Chinese gPrD patients identified between Jan 2006 and June 2020. Nineteen different subtypes were identified and gPrDs accounted for 10.9% of all diagnosed PrDs within the same period. Some subtypes of gPrDs showed a degree of geographic association. The age at onset of Chinese gPrDs peaked in the 50-59 year group. Gerstmann-Sträussler-Scheinker syndrome (GSS) and fatal familial insomnia (FFI) cases usually displayed clinical symptoms earlier than genetic Creutzfeldt-Jakob disease (gCJD) patients with point mutations. A family history was more frequently recalled in P105L GSS and D178N FFI patients than T188K and E200K patients. None of the E196A gCJD patients reported a family history. The gCJD cases with point mutations always developed clinical manifestations typical of sporadic CJD (sCJD). EEG examination was not sensitive for gPrDs. sCJD-associated abnormalities on MRI were found in high proportions of GSS and gCJD patients. CSF 14-3-3 positivity was frequently detected in gCJD patients. Increased CSF tau was found in more than half of FFI and T188K gCJD cases, and an even higher proportion of E196A and E200K gCJD patients. 63.6% of P105L GSS cases showed a positive reaction in cerebrospinal fluid RT-QuIC. GSS and FFI cases had longer durations than most subtypes of gCJD. This is one of the largest studies of gPrDs in East Asians, and the illness profile of Chinese gPrDs is clearly distinct. Extremely high proportions of T188K and E196A occur among Chinese gPrDs; these mutations are rarely reported in Caucasians and Japanese.
14-3-3 Proteins/cerebrospinal fluid* ; China ; Creutzfeldt-Jakob Syndrome/genetics* ; Humans ; Mutation/genetics* ; Prion Diseases/genetics* ; Prion Proteins/genetics* ; Prions/genetics* ; tau Proteins/cerebrospinal fluid*

In order to establish an amplification system in vitro with which the PrP(Sc) is able to convert PrP(C) into proteinase K-resistant isoform infinitely and whether this system is more efficient than conventional protein misfolding cyclic amplification (PMCA), scrapie strain 263K-infected hamster's brain homogenate and homologous normal brain homogenate were prepared, respectively. A new methodology, namely serial PMCA, was utilized to reveal the continuous propagation ability of PrP(Sc). Totally 8 rounds of serial PMCA were proceeded and each round contained 48 cycles of alternative sonication and incubation. Simultaneously 144 cycles of conventional PMCA was used as a control. The results showed the PrP(Sc) from hamsters' brain tissues of scrapie agent 263K could replicate efficiently and infinitely with serial PMCA compared with finite propagation of PrP(Sc) with conventional PMCA system. The study of PrP(Sc) continuous propagation in brain homogenate with serial PMCA may further provide insight into the unsettled mechanism of prions misfolding and replication and apply to detect trace amount of PrP(Sc).
Animals ; Brain ; metabolism ; Cricetinae ; PrPC Proteins ; chemistry ; PrPSc Proteins ; chemistry ; Protein Folding

OBJECTIVETo obtain monoclonal antibodies (McAbs) which can be widely used to detect mammalian prions (PrP) and to develop diagnostic tests for screening transmissile spongiform encephalopathies (TSE) as well as for studying pathogenesis of prion-related diseases.

METHODSBALB/c mice were immunized separately with bovine PrP peptide 29-48 (BoP1) and 89-108 (BoP2) coupled to keyhole limpt hemocyan. Two hybridoma cell lines secreting monoclonal antibodies against these peptides were established by cell fusion and 2 to 3 rounds of cell cloning. The reactions of the McAbs to the recombinant bovine (Bo)PrP(25-242), human (Hu)PrP(23-231) and hamster (Ha) PrP (23?231) were tested separately by Western blotting.

RESULTSThrough cell fusion, two hybridoma cell lines secreting McAbs against BoP1 and BoP2, designated D11 and D8 accordingly, were identified by ELISA and cell cloning. The McAbs produced by these cell lines reacted well with the recombinant PrP proteins; (Bo) PrP (25-242), (Hu) PrP (23-231), and (Ha) PrP (23-231), respectively.

CONCLUSIONSTwo McAbs reacting with bovine, human and hamster PrPs were successfully generated, they are potential to be used to detect PrPs in mammals and to study the mechanism of pathogenesis of TSE.

Animals ; Antibodies, Monoclonal ; biosynthesis ; Antibodies, Viral ; biosynthesis ; immunology ; Antibody Specificity ; Cattle ; Cricetinae ; Cross Reactions ; Encephalopathy, Bovine Spongiform ; prevention & control ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Hybridomas ; secretion ; Male ; Mice ; Mice, Inbred BALB C ; PrPSc Proteins ; immunology ; Prion Diseases ; prevention & control ; Prions ; immunology ; Recombinant Fusion Proteins ; biosynthesis ; immunology

To explore the possible molecular interaction between CK2 and PrP, the full length sequences of human CK2alpha and CK2beta genes were amplified with RT-PCR using the mRNA from cell line SH-SY5Y as the template, and then the fusion proteins HIS-CK2alpha and GST-HIS-CK2beta were expressed in E. coli. The interaction between CK2 and PrP was evaluated with immunoprecipitation and pull-down assays. The results demonstrated that recombinant PrP bound specifically with CK2alpha, but not with CK2beta. The native CK2 and PrP in the hamster brains interacted each other, forming protein complexes. The domain responsible for interacting with CK2alpha was located at the C-terminal segment of PrP (residues 90-231). This study proposed reliable experimental data for the molecular interaction between PrP and CK2alpha, both in recombinant and native categories. These results supply scientific clues for further assessing the potential biological significance of the interaction of PrP with CK2 and possible role of CK2 in the pathogenesis of prion diseases.
Animals ; Casein Kinase II ; chemistry ; physiology ; Cricetinae ; Humans ; Immunoprecipitation ; Phosphorylation ; Prion Diseases ; etiology ; Prions ; chemistry ; Recombinant Proteins ; chemistry

OBJECTIVETo investigate epidemiological, clinical and genetic features of the first Chinese case of Creutzfeldt-Jakob disease (CJD ) with mutation of E200K in PRNP.

METHODSThe general epidemiological and clinical data were collected; CSF 14-3-3 protein was analyzed by Western blot; The PRNP was amplified by PCR and analyzed.

RESULTSA missense mutation in codon 200 (E200K) of the PRNP was identified in this patient; CSF 14-3-3 protein was positive; sleep disturbance was the initial sign and the other symptoms gradually appeared, including memory loss, dizziness and ataxia.

CONCLUSIONThe CJD patient who was first reported in China has a missense mutation in codon 200 (E200K) of the PRNP, and the codon 129 is a methionine homozygous genotype.

Asian Continental Ancestry Group ; China ; Creutzfeldt-Jakob Syndrome ; genetics ; Humans ; Male ; Middle Aged ; Mutation, Missense ; Prion Proteins ; Prions ; genetics

OBJECTIVETo create transgenic mice expressing hamster- and human-PRNP as a model for understanding the physiological function and pathology of prion protein (PrP), as well as the mechanism of cross-species transmission of transmissible spongiform encephalopathies (TSEs).

METHODSHamster and human-PRNP transgenic mice were established by conventional methods. The copy number of integrated PRNP in various mouse lines was mapped by real-time PCR. PRNP mRNA and protein levels were determined by semi-quantitative RT-PCR, real-time RT-PCR, and western blot analysis. Histological analyses of transgenic mice were performed by hematoxylin and eosin (H & E) staining and immunohistochemical (IHC) methods.

RESULTSIntegrated PRNP copy number in various mouse lines was 53 (Tg-haPrP1), 18 (Tg-huPrP1), 3 (Tg-huPrP2), and 16 (Tg-huPrP5), respectively. Exogenous PrPs were expressed at both the transcriptional and translational level. Histological assays did not detect any abnormalities in brain or other organs.

CONCLUSIONWe have established one hamster-PRNP transgenic mouse line and three human-PRNP transgenic mouse lines. These four transgenic mouse lines provide ideal models for additional research.

Animals ; Blotting, Western ; Cricetinae ; DNA ; genetics ; Disease Models, Animal ; Humans ; Immunohistochemistry ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Organ Specificity ; Plasmids ; Prion Diseases ; genetics ; Prion Proteins ; Prions ; genetics ; Real-Time Polymerase Chain Reaction ; Transcription, Genetic