RESUMO
Variant Creutzfeldt-Jakob disease (vCJD) is a human prion disease resulting from zoonotic transmission of bovine spongiform encephalopathy (BSE). Documented cases of vCJD transmission by blood transfusion necessitate on-going risk reduction measures to protect blood supplies, such as leucodepletion (removal of white blood cells, WBCs). This study set out to determine the risks of prion transmission by transfusion of labile blood components (red blood cells, platelets, plasma) commonly used in human medicine, and the effectiveness of leucodepletion in preventing infection, using BSE-infected sheep as a model. All components were capable of transmitting prion disease when donors were in the preclinical phase of infection, with the highest rates of infection in recipients of whole blood and buffy coat, and the lowest in recipients of plasma. Leucodepletion of components (<106 WBCs/unit) resulted in significantly lower transmission rates, but did not completely prevent transmission by any component. Donor PRNP genotype at codon 141, which is associated with variation in incubation period, also had a significant effect on transfusion transmission rates. A sensitive protein misfolding cyclic amplification (PMCA) assay, applied to longitudinal series of blood samples, identified infected sheep from 4 months post infection. However, in donor sheep (orally infected), the onset of detection of PrPSc in blood was much more variable, and generally later, compared to recipients (intravenous infection). This shows that the route and method of infection may profoundly affect the period during which an individual is infectious, and the test sensitivity required for reliable preclinical diagnosis, both of which have important implications for disease control. Our results emphasize that blood transfusion can be a highly efficient route of transmission for prion diseases. Given current uncertainties over the prevalence of asymptomatic vCJD carriers, this argues for the maintenance and improvement of current measures to reduce the risk of transmission by blood products.
Assuntos
Doadores de Sangue/estatística & dados numéricos , Transfusão de Sangue/métodos , Encéfalo/metabolismo , Encefalopatia Espongiforme Bovina/genética , Encefalopatia Espongiforme Bovina/transmissão , Proteínas PrPSc/metabolismo , Príons/patogenicidade , Animais , Bovinos , Encefalopatia Espongiforme Bovina/sangue , Genótipo , Camundongos , Proteínas PrPSc/genética , Príons/genética , OvinosRESUMO
Among the numerous transmissible spongiform encephalopathies (TSEs), bovine spongiform encephalopathy (BSE) is the most well-known TSEs. It is a potential Creutzfeldt-Jakob (CJD) disease mutation that can be transferred through cattle to humans. In several animals, the prion protein gene (PRNP) is recognized to take active part in TSE vulnerability or tolerance. Previous studies have found indels polymorphism in PRNP gene promoter and intron1 region linked to BSE vulnerability. It's linked with 23 bp indels polymorphism in putative promoter and 12 bp indel in intron 1 of the PRNP gene. The aim of this study was to compare the allele, genotype and haplotype frequencies of PRNP indel polymorphisms in Zhongdian Yak (Bos grunniens) (YK), Zhongdian Yellow cattle (Bos taurus) (YC) and Zhongdian Yakow (Bos primigenius taurus × Bos grunniens) (PK) with worldwide reported healthy or affected BSE cattle, in order to assess their potential resistance to BSE. A comparison of Chinese bovine populations with healthy and BSE-affected German and Swiss cattle from globally was conducted, and result indicating significant difference (p < .001) between healthy and affected cattle. Additionally, as compared to prior studies with Chinese bovine population, the significant results were found. In this study, the allelic frequency D23 finding high deletion in all analyzed Chinese bovine species, and haplotype D12-D23 exhibited a less significant inclination toward susceptibility to BSE.
Assuntos
Doenças dos Bovinos , Encefalopatia Espongiforme Bovina , Príons , Animais , Bovinos/genética , Encefalopatia Espongiforme Bovina/genética , Frequência do Gene/genética , Polimorfismo Genético/genética , Proteínas Priônicas/genética , Príons/genéticaRESUMO
Susceptibility to classical bovine spongiform encephalopathy (BSE) has been linked to 23 bp indel in promoter and 12 bp indel in the first intron of cattle prion protein gene. This study aimed to investigate 23/12 bp indel polymorphisms in the polymorphisms in cattle prion protein (PRNP) gene to reveal the risk of BSE in Ethiopian cattle. Also, frequency of each polymorphism was compared to the other Bos taurus and Bos indicus breeds. According to results, the insertion variant was detected at a low frequency in all of the study populations at both loci. The 23 bp insertion allele in Fogera breed was relatively lower than Borona and Arsi and the same allele at the same locus in Afar breed was higher than the rest of the breeds (0.16). Due to high linkage disequilibrium (LD) of the deletion allele in Bos taurus, the frequencies of deletion allele at 23 bp (0.84) and 12 bp (0.86) loci in Afar breed were relatively closer than the rest of the breeds. In addition, DD/DD was found as the highly frequent diplotype in all of the breeds. The low frequency of insertion alleles at 23 and 12 bp indel sites demonstrate that Ethiopian cattle have a genetically high risk for BSE.
Assuntos
Doenças dos Bovinos , Encefalopatia Espongiforme Bovina , Príons , Bovinos/genética , Animais , Proteínas Priônicas/genética , Príons/genética , Encefalopatia Espongiforme Bovina/epidemiologia , Encefalopatia Espongiforme Bovina/genética , Polimorfismo Genético/genética , Regiões Promotoras Genéticas , Frequência do Gene , Doenças dos Bovinos/genéticaRESUMO
Mammalian prions, transmissible agents causing lethal neurodegenerative diseases, are composed of assemblies of misfolded cellular prion protein (PrP). A novel PrP variant, G127V, was under positive evolutionary selection during the epidemic of kuru--an acquired prion disease epidemic of the Fore population in Papua New Guinea--and appeared to provide strong protection against disease in the heterozygous state. Here we have investigated the protective role of this variant and its interaction with the common, worldwide M129V PrP polymorphism. V127 was seen exclusively on a M129 PRNP allele. We demonstrate that transgenic mice expressing both variant and wild-type human PrP are completely resistant to both kuru and classical Creutzfeldt-Jakob disease (CJD) prions (which are closely similar) but can be infected with variant CJD prions, a human prion strain resulting from exposure to bovine spongiform encephalopathy prions to which the Fore were not exposed. Notably, mice expressing only PrP V127 were completely resistant to all prion strains, demonstrating a different molecular mechanism to M129V, which provides its relative protection against classical CJD and kuru in the heterozygous state. Indeed, this single amino acid substitution (GâV) at a residue invariant in vertebrate evolution is as protective as deletion of the protein. Further study in transgenic mice expressing different ratios of variant and wild-type PrP indicates that not only is PrP V127 completely refractory to prion conversion but acts as a potent dose-dependent inhibitor of wild-type prion propagation.
Assuntos
Polimorfismo Genético/genética , Doenças Priônicas/genética , Doenças Priônicas/prevenção & controle , Príons/genética , Príons/metabolismo , Alelos , Substituição de Aminoácidos/genética , Animais , Bovinos , Síndrome de Creutzfeldt-Jakob/genética , Síndrome de Creutzfeldt-Jakob/prevenção & controle , Encefalopatia Espongiforme Bovina/genética , Feminino , Heterozigoto , Homozigoto , Humanos , Kuru/epidemiologia , Kuru/genética , Kuru/prevenção & controle , Camundongos , Camundongos Transgênicos , Papua Nova Guiné/epidemiologia , Proteínas PrPSc/química , Proteínas PrPSc/genética , Proteínas PrPSc/metabolismo , Doenças Priônicas/epidemiologia , Doenças Priônicas/transmissão , Príons/química , Príons/farmacologiaRESUMO
BACKGROUND: Transmissible mink encephalopathy (TME) is a fatal neurologic disease of farmed mink. Evidence indicates that TME and L-BSE are similar and may be linked in some outbreaks of TME. We previously transmitted bovine adapted TME (bTME) to sheep. The present study compared ovine passaged bTME (o-bTME) to C-BSE and L-BSE in transgenic mice expressing wild type bovine prion protein (TgBovXV). To directly compare the transmission efficiency of all prion strains in this study, we considered the attack rates and mean incubation periods. Additional methods for strain comparison were utilized including lesion profiles, fibril stability, and western blotting. RESULTS: Sheep donor genotype elicited variable disease phenotypes in bovinized mice. Inoculum derived from a sheep with the VRQ/VRQ genotype (o-bTMEVV) resulted in an attack rate, incubation period, western blot profile, and neuropathology most similar to bTME and L-BSE. Conversely, donor material from a sheep with the VRQ/ARQ genotype (o-bTMEAV) elicited a phenotype distinct from o-bTMEVV, bTME and L-BSE. The TSE with the highest transmission efficiency in bovinized mice was L-BSE. The tendency to efficiently transmit to TgBovXV mice decreased in the order bTME, C-BSE, o-bTMEVV, and o-bTMEAV. The transmission efficiency of L-BSE was approximately 1.3 times higher than o-bTMEVV and 3.2 times higher than o-bTMEAV. CONCLUSIONS: Our findings provide insight on how sheep host genotype modulates strain genesis and influences interspecies transmission characteristics. Given that the transmission efficiencies of L-BSE and bTME are higher than C-BSE, coupled with previous reports of L-BSE transmission to mice expressing the human prion protein, continued monitoring for atypical BSE is advisable in order to prevent occurrences of interspecies transmission that may affect humans or other species.
Assuntos
Doenças Priônicas/genética , Doenças Priônicas/transmissão , Proteínas Priônicas/genética , Príons/genética , Animais , Encéfalo/patologia , Bovinos , Encefalopatia Espongiforme Bovina/genética , Encefalopatia Espongiforme Bovina/patologia , Encefalopatia Espongiforme Bovina/transmissão , Camundongos Transgênicos , Proteínas PrPC/genética , Doenças Priônicas/patologiaRESUMO
Bovine spongiform encephalopathy (BSE) is a prion disease characterized by spongiform degeneration and astrocytosis in the brain. Unlike classical BSE, which is caused by prion-disease-contaminated meat and bone meal, the cause of atypical BSE has not been determined. Since previous studies have reported that the somatic mutation in the human prion protein gene (PRNP) has been linked to human prion disease, the somatic mutation of the PRNP gene was presumed to be one cause of prion disease. However, to the best of our knowledge, the somatic mutation of this gene in cattle has not been investigated to date. We investigated somatic mutations in a total of 58 samples, including peripheral blood; brain tissue including the medulla oblongata, cerebellum, cortex, and thalamus; and skin tissue in 20 individuals from each breed using pyrosequencing. In addition, we estimated the deleterious effect of the K211 somatic mutation on bovine prion protein by in silico evaluation tools, including PolyPhen-2 and PANTHER. We found a high rate of K211 somatic mutations of the bovine PRNP gene in the medulla oblongata of three Holsteins (10% ± 4.4%, 28% ± 2%, and 19.55% ± 3.1%). In addition, in silico programs showed that the K211 somatic mutation was damaging. To the best of our knowledge, this study is the first to investigate K211 somatic mutations of the bovine PRNP gene that are associated with potential BSE progression.
Assuntos
Encefalopatia Espongiforme Bovina/genética , Sequenciamento de Nucleotídeos em Larga Escala/veterinária , Mutação , Proteínas Priônicas/genética , Animais , Bovinos , Simulação por Computador , Progressão da Doença , Encefalopatia Espongiforme Bovina/metabolismo , Feminino , Predisposição Genética para Doença , Masculino , Bulbo/metabolismo , Taxa de Mutação , Proteínas Priônicas/metabolismo , Análise de Sequência de DNA/veterináriaRESUMO
Conformational conversion of the cellular prion protein, PrPC, into the abnormally folded isoform, PrPSc, is a key pathogenic event in prion diseases. However, the exact conversion mechanism remains largely unknown. Transgenic mice expressing PrP with a deletion of the central residues 91-106 were generated in the absence of endogenous PrPC, designated Tg(PrP∆91-106)/Prnp0/0 mice and intracerebrally inoculated with various prions. Tg(PrP∆91-106)/Prnp0/0 mice were resistant to RML, 22L and FK-1 prions, neither producing PrPSc∆91-106 or prions in the brain nor developing disease after inoculation. However, they remained marginally susceptible to bovine spongiform encephalopathy (BSE) prions, developing disease after elongated incubation times and accumulating PrPSc∆91-106 and prions in the brain after inoculation with BSE prions. Recombinant PrP∆91-104 converted into PrPSc∆91-104 after incubation with BSE-PrPSc-prions but not with RML- and 22L-PrPSc-prions, in a protein misfolding cyclic amplification assay. However, digitonin and heparin stimulated the conversion of PrP∆91-104 into PrPSc∆91-104 even after incubation with RML- and 22L-PrPSc-prions. These results suggest that residues 91-106 or 91-104 of PrPC are crucially involved in prion pathogenesis in a strain-dependent manner and may play a similar role to digitonin and heparin in the conversion of PrPC into PrPSc.
Assuntos
Encefalopatia Espongiforme Bovina/genética , Proteínas PrPC/genética , Proteínas PrPSc/genética , Deficiências na Proteostase/genética , Scrapie/genética , Deleção de Sequência , Animais , Baculoviridae/genética , Baculoviridae/metabolismo , Sequência de Bases , Encéfalo/metabolismo , Encéfalo/patologia , Bovinos , Clonagem Molecular , Suscetibilidade a Doenças , Encefalopatia Espongiforme Bovina/metabolismo , Encefalopatia Espongiforme Bovina/patologia , Expressão Gênica , Injeções Intraventriculares , Camundongos , Camundongos Transgênicos , Proteínas PrPC/química , Proteínas PrPC/metabolismo , Proteínas PrPSc/administração & dosagem , Proteínas PrPSc/química , Proteínas PrPSc/metabolismo , Deficiências na Proteostase/metabolismo , Deficiências na Proteostase/patologia , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Scrapie/metabolismo , Scrapie/patologia , Especificidade da EspécieRESUMO
The structure of the infectious prion protein (PrPSc), which is responsible for Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy, has escaped all attempts at elucidation due to its insolubility and propensity to aggregate. PrPSc replicates by converting the non-infectious, cellular prion protein (PrPC) into the misfolded, infectious conformer through an unknown mechanism. PrPSc and its N-terminally truncated variant, PrP 27-30, aggregate into amorphous aggregates, 2D crystals, and amyloid fibrils. The structure of these infectious conformers is essential to understanding prion replication and the development of structure-based therapeutic interventions. Here we used the repetitive organization inherent to GPI-anchorless PrP 27-30 amyloid fibrils to analyze their structure via electron cryomicroscopy. Fourier-transform analyses of averaged fibril segments indicate a repeating unit of 19.1 Å. 3D reconstructions of these fibrils revealed two distinct protofilaments, and, together with a molecular volume of 18,990 Å3, predicted the height of each PrP 27-30 molecule as ~17.7 Å. Together, the data indicate a four-rung ß-solenoid structure as a key feature for the architecture of infectious mammalian prions. Furthermore, they allow to formulate a molecular mechanism for the replication of prions. Knowledge of the prion structure will provide important insights into the self-propagation mechanisms of protein misfolding.
Assuntos
Amiloide/ultraestrutura , Proteínas PrPC/ultraestrutura , Proteínas PrPSc/ultraestrutura , Amiloide/genética , Animais , Bovinos , Síndrome de Creutzfeldt-Jakob/genética , Síndrome de Creutzfeldt-Jakob/metabolismo , Síndrome de Creutzfeldt-Jakob/patologia , Microscopia Crioeletrônica , Encefalopatia Espongiforme Bovina/genética , Encefalopatia Espongiforme Bovina/metabolismo , Encefalopatia Espongiforme Bovina/patologia , Humanos , Proteínas PrPC/genética , Proteínas PrPSc/genéticaRESUMO
In animal prion diseases, including bovine spongiform encephalopathy (BSE) in cattle, chronic wasting disease in cervids, and scrapie in sheep and goats, a disease-associated isoform of prion protein (PrPd) accumulates in the brains of affected animals. Although the CH1641 scrapie isolate was experimentally established in the UK, a few natural CH1641-like scrapie cases have been reported in France and the UK. The molecular mass of the unglycosylated protease-resistant core of PrPd (PrPres) is known to be similar between CH1641-like scrapie and experimental BSE in sheep. We previously established an experimental CH1641-like scrapie isolate (Sh294) from a natural classical scrapie case. Here, we demonstrated that the Sh294 isolate was independent of both classical and atypical BSEs by cross-species transmission to bovine PrP overexpressing (TgBoPrP) mice and wild-type mice. Interestingly, we found that the Sh294 isolate altered its host range by the transmission to TgBoPrP mice, and we succeeded in the first stable reproduction of CH1641-like scrapie specific PrPres banding patterns with the ~12-kDa small C-terminal fragment in wild-type mice. This study provides new insight into the relationship between CH1641-like scrapie isolates and BSEs. In addition, interspecies transmission models such as we have demonstrated here could be a great help to investigate the origin and host range of animal prions.
Assuntos
Encefalopatia Espongiforme Bovina/genética , Proteínas PrPSc/genética , Doenças Priônicas , Príons/genética , Scrapie/genética , Animais , Encéfalo/metabolismo , Bovinos , Encefalopatia Espongiforme Bovina/metabolismo , Camundongos , Camundongos Transgênicos , Proteínas Priônicas , Scrapie/metabolismo , OvinosRESUMO
Resistance to bovine spongiform encephalopathy (BSE) that is significantly associated with insertion/deletion (indel) polymorphisms at two loci (putative promoter and intron 1) on the prion protein gene (PRNP) in cattle has been well documented. Studies suggest that the insertion alleles are related to BSE resistance. Until recently, BSE has never been reported in water buffaloes (unlike cattle). Previous studies have demonstrated that the PRNP gene in water buffalo consists mostly of insertion alleles at both loci; nevertheless, whether or not water buffaloes are genetically resistant to BSE and the role of indel polymorphisms in their resistance status is not clear. We examined the coding region of PRNP to determine the nucleotide and octapeptide-repeat (octarepeats) variations of Anatolian, Murrah and Murrah × Anatolian (M × A) water buffaloes. Three synonymous single nucleotide polymorphisms (SNP) at positions 126, 234, and 285, and a non-synonymous SNP at position 322 (G108S) were detected. Triplet G/A/T base substitutions were observed at position 126 and two additional genotypes, T/A and T/G, at this position were determined. We also found six octarepeats that indicated the presence of the wild-type PRNP6 allele in the coding region. To the best of our knowledge, this is the first report of the T/A and T/G genotypes in water buffaloes.
Assuntos
Cruzamento , Cruzamentos Genéticos , Encefalopatia Espongiforme Bovina/genética , Polimorfismo de Nucleotídeo Único , Proteínas Priônicas/genética , Príons/genética , Alelos , Animais , Búfalos/genética , Bovinos , Éxons , Genótipo , Mutação INDEL , Íntrons , Nucleotídeos/genética , Fases de Leitura Aberta , Polimorfismo Genético , Regiões Promotoras Genéticas , Especificidade da EspécieRESUMO
Chronic wasting disease (CWD) in cervids and bovine spongiform encephalopathy (BSE) in cattle are prion diseases that are caused by the same protein-misfolding mechanism, but they appear to pose different risks to humans. We are interested in understanding the differences between the species barriers of CWD and BSE. We used real-time, quaking-induced conversion (RT-QuIC) to model the central molecular event in prion disease, the templated misfolding of the normal prion protein, PrPc, to a pathogenic, amyloid isoform, scrapie prion protein, PrPSc We examined the role of the PrPc amino-terminal domain (N-terminal domain [NTD], amino acids [aa] 23 to 90) in cross-species conversion by comparing the conversion efficiency of various prion seeds in either full-length (aa 23 to 231) or truncated (aa 90 to 231) PrPc We demonstrate that the presence of white-tailed deer and bovine NTDs hindered seeded conversion of PrPc, but human and bank vole NTDs did the opposite. Additionally, full-length human and bank vole PrPcs were more likely to be converted to amyloid by CWD prions than were their truncated forms. A chimera with replacement of the human NTD by the bovine NTD resembled human PrPc The requirement for an NTD, but not for the specific human sequence, suggests that the NTD interacts with other regions of the human PrPc to increase promiscuity. These data contribute to the evidence that, in addition to primary sequence, prion species barriers are controlled by interactions of the substrate NTD with the rest of the substrate PrPc molecule. IMPORTANCE: We demonstrate that the amino-terminal domain of the normal prion protein, PrPc, hinders seeded conversion of bovine and white-tailed deer PrPcs to the prion forms, but it facilitates conversion of the human and bank vole PrPcs to the prion forms. Additionally, we demonstrate that the amino-terminal domain of human and bank vole PrPcs requires interaction with the rest of the molecule to facilitate conversion by CWD prions. These data suggest that interactions of the amino-terminal domain with the rest of the PrPc molecule play an important role in the susceptibility of humans to CWD prions.
Assuntos
Proteínas PrPC/genética , Proteínas PrPC/patogenicidade , Doenças Priônicas/etiologia , Sequência de Aminoácidos , Animais , Arvicolinae , Encéfalo/metabolismo , Bovinos , Cervos , Suscetibilidade a Doenças , Encefalopatia Espongiforme Bovina/etiologia , Encefalopatia Espongiforme Bovina/genética , Encefalopatia Espongiforme Bovina/metabolismo , Especificidade de Hospedeiro/genética , Humanos , Proteínas PrPC/química , Doenças Priônicas/genética , Doenças Priônicas/metabolismo , Dobramento de Proteína , Domínios e Motivos de Interação entre Proteínas , Homologia de Sequência de Aminoácidos , Doença de Emaciação Crônica/etiologia , Doença de Emaciação Crônica/genética , Doença de Emaciação Crônica/metabolismoRESUMO
Prions are proteinaceous pathogens responsible for subacute spongiform encephalopathies in animals and humans. The prions responsible for bovine spongiform encephalopathy (BSE) are zoonotic agents, causing variant Creutzfeldt-Jakob disease (CJD) in humans. The transfer of prions between species is limited by a species barrier, which is thought to reflect structural incompatibilities between the host cellular prion protein (PrPC) and the infecting pathological PrP assemblies (PrPSc) constituting the prion. A BSE strain variant, designated L-BSE and responsible for atypical, supposedly spontaneous forms of prion diseases in aged cattle, demonstrates zoonotic potential, as evidenced by its capacity to propagate more easily than classical BSE in transgenic mice expressing human PrPC and in nonhuman primates. In humanized mice, L-BSE propagates without any apparent species barrier and shares similar biochemical PrPSc signatures with the CJD subtype designated MM2-cortical, thus opening the possibility that certain CJD cases classified as sporadic may actually originate from L-type BSE cross-transmission. To address this issue, we compared the biological properties of L-BSE and those of a panel of CJD subtypes representative of the human prion strain diversity using standard strain-typing criteria in human PrP transgenic mice. We found no evidence that L-BSE causes a known form of sporadic CJD. IMPORTANCE: Since the quasi-extinction of classical BSE, atypical BSE forms are the sole BSE variants circulating in cattle worldwide. They are observed in rare cases of old cattle, making them difficult to detect. Extrapolation of our results suggests that L-BSE may propagate in humans as an unrecognized form of CJD, and we urge both the continued utilization of precautionary measures to eliminate these agents from the human food chain and active surveillance for CJD phenotypes in the general population.
Assuntos
Síndrome de Creutzfeldt-Jakob/genética , Encefalopatia Espongiforme Bovina/genética , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Bovinos , Síndrome de Creutzfeldt-Jakob/etiologia , Síndrome de Creutzfeldt-Jakob/transmissão , Modelos Animais de Doenças , Encefalopatia Espongiforme Bovina/etiologia , Encefalopatia Espongiforme Bovina/transmissão , Variação Genética , Especificidade de Hospedeiro , Humanos , Camundongos , Camundongos Transgênicos , Proteínas PrPC/genética , Proteínas PrPC/patogenicidade , Proteínas PrPSc/genética , Proteínas PrPSc/patogenicidadeRESUMO
Breeding towards genetic resistance to prion disease is effective in eliminating scrapie. In sheep, classical forms of scrapie have been eradicated almost completely in several countries by breeding programs using a prion protein (PrP) gene (PRNP) amino acid polymorphism. For goats, field and experimental studies have provided evidence for several amino acid polymorphisms that are associated with resistance to scrapie, but only limited data are available concerning the susceptibility of caprine PRNP genotypes to BSE. In this study, goat kids representing five PRNP genotypes based on three polymorphisms (M142, Q211 and K222 and the wild type I142, R211 and Q222) were orally challenged with bovine or goat BSE. Wild type goats were killed with clinical signs between 24-28 months post inoculation (mpi) to both challenges, and goats with genotype R/Q211 succumbed between 29-36 mpi. I/M142 goats developed clinical signs at 44-45 mpi and M/M142 goats remained healthy until euthanasia at 48 mpi. None of the Q/K222 goats showed definite clinical signs. Taken together the highest attack ratios were seen in wild type and R/Q211 goats, and the lowest in I/M142, M/M142 and Q/K222. In all genotype groups, one or more goats remained healthy within the incubation period in both challenges and without detectable PrP deposition in the tissues. Our data show that both the K222 and M142 polymorphisms lengthen the incubation period significantly compared to wild type animals, but only K222 was associated with a significant increase in resistance to BSE infection after oral exposure to both BSE sources.
Assuntos
Resistência à Doença/genética , Encefalopatia Espongiforme Bovina/prevenção & controle , Doenças das Cabras/prevenção & controle , Príons/efeitos adversos , Animais , Cruzamento , Bovinos , Códon/genética , Encefalopatia Espongiforme Bovina/genética , Feminino , Doenças das Cabras/genética , Doenças das Cabras/patologia , Cabras , Masculino , Proteínas PriônicasRESUMO
Bovine spongiform encephalopathy (BSE) of the cattle is the outstanding disease among other transmissible spongiform encephalopathy (TSEs). It can be transmitted from the cattle to a human and causes a new variant of the Creutzfeldt-Jakob disease (CJD). It is known that prion protein coding gene (PRNP) plays a major role in the TSE susceptibility or resistance in some species. Recent researches demonstrated that the insertion (in) and deletion (del) polymorphisms within promoter and intron 1 region of the PRNP related to BSE susceptibility in cattle. In contrast to cattle, BSE has never been reported in water buffalo; hence, PRNP polymorphisms may be an explanation for buffalo resistance to BSE. The aim of this study was to evaluate allele, genotype, and haplotype frequencies of the PRNP promoter and intron 1 insertion/deletion (indel) polymorphism in healthy Anatolian, Murrah, and Murrah × Anatolian crossbred buffaloes. According to our findings, there were no deletion alleles at two mentioned loci. All studied buffaloes were monomorphic and have carried in/in haplotypes which are considered as the most resistant genotype to BSE.
Assuntos
Búfalos/genética , Encefalopatia Espongiforme Bovina/genética , Polimorfismo Genético , Proteínas Priônicas/genética , Alelos , Animais , Bovinos , Deleção de Genes , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Haplótipos , Mutação INDEL , Íntrons , Príons/genética , Regiões Promotoras GenéticasRESUMO
Bank voles are uniquely susceptible to a wide range of prion strains isolated from many different species. To determine if this enhanced susceptibility to interspecies prion transmission is encoded within the sequence of the bank vole prion protein (BVPrP), we inoculated Tg(M109) and Tg(I109) mice, which express BVPrP containing either methionine or isoleucine at polymorphic codon 109, with 16 prion isolates from 8 different species: humans, cattle, elk, sheep, guinea pigs, hamsters, mice, and meadow voles. Efficient disease transmission was observed in both Tg(M109) and Tg(I109) mice. For instance, inoculation of the most common human prion strain, sporadic Creutzfeldt-Jakob disease (sCJD) subtype MM1, into Tg(M109) mice gave incubation periods of â¼200 days that were shortened slightly on second passage. Chronic wasting disease prions exhibited an incubation time of â¼250 days, which shortened to â¼150 days upon second passage in Tg(M109) mice. Unexpectedly, bovine spongiform encephalopathy and variant CJD prions caused rapid neurological dysfunction in Tg(M109) mice upon second passage, with incubation periods of 64 and 40 days, respectively. Despite the rapid incubation periods, other strain-specified properties of many prion isolates--including the size of proteinase K-resistant PrPSc, the pattern of cerebral PrPSc deposition, and the conformational stability--were remarkably conserved upon serial passage in Tg(M109) mice. Our results demonstrate that expression of BVPrP is sufficient to engender enhanced susceptibility to a diverse range of prion isolates, suggesting that BVPrP may be a universal acceptor for prions.
Assuntos
Arvicolinae/metabolismo , Proteínas PrPSc/metabolismo , Animais , Arvicolinae/genética , Encéfalo/metabolismo , Encéfalo/patologia , Bovinos , Síndrome de Creutzfeldt-Jakob/genética , Síndrome de Creutzfeldt-Jakob/metabolismo , Síndrome de Creutzfeldt-Jakob/patologia , Cricetinae , Encefalopatia Espongiforme Bovina/genética , Encefalopatia Espongiforme Bovina/metabolismo , Encefalopatia Espongiforme Bovina/patologia , Cobaias , Humanos , Camundongos , Camundongos Transgênicos , Proteínas PrPSc/genética , OvinosRESUMO
Prion diseases are rare fatal neurological conditions of humans and animals, one of which (variant Creutzfeldt-Jakob disease) is known to be a zoonotic form of the cattle disease bovine spongiform encephalopathy (BSE). What makes one animal prion disease zoonotic and others not is poorly understood, but it appears to involve compatibility between the prion strain and the host prion protein sequence. Concerns have been raised that the United Kingdom sheep flock may have been exposed to BSE early in the cattle BSE epidemic and that serial BSE transmission in sheep might have resulted in adaptation of the agent, which may have come to phenotypically resemble scrapie while maintaining its pathogenicity for humans. We have modeled this scenario in vitro. Extrapolation from our results suggests that if BSE were to infect sheep in the field it may, with time and in some sheep genotypes, become scrapie-like at the molecular level. However, the results also suggest that if BSE in sheep were to come to resemble scrapie it would lose its ability to affect humans.
Assuntos
Encefalopatia Espongiforme Bovina/transmissão , Príons/genética , Scrapie/transmissão , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Bovinos , Encefalopatia Espongiforme Bovina/genética , Evolução Molecular , Genótipo , Glicosilação , Humanos , Príons/metabolismo , Dobramento de Proteína , Processamento de Proteína Pós-Traducional , Scrapie/genética , Carneiro Doméstico , ZoonosesRESUMO
UNLABELLED: The prion protein-encoding gene (prnp) strongly influences the susceptibility of small ruminants to transmissible spongiform encephalopathies (TSEs). Hence, selective breeding programs have been implemented to increase sheep resistance to scrapie. For goats, epidemiological and experimental studies have provided some association between certain polymorphisms of the cellular prion protein (PrP(C)) and resistance to TSEs. Among them, the Q/K polymorphism at PrP(C) codon 222 (Q/K222) yielded the most promising results. In this work, we investigated the individual effects of the K222-PrP(C) variant on the resistance/susceptibility of goats to TSEs. For that purpose, we generated two transgenic mouse lines, expressing either the Q222 (wild type) or K222 variant of goat PrP(C). Both mouse lines were challenged intracerebrally with a panel of TSE isolates. Transgenic mice expressing the wild-type (Q222) allele were fully susceptible to infection with all tested isolates, whereas transgenic mice expressing similar levels of the K222 allele were resistant to all goat scrapie and cattle BSE isolates but not to goat BSE isolates. Finally, heterozygous K/Q222 mice displayed a reduced susceptibility to the tested panel of scrapie isolates. These results demonstrate a highly protective effect of the K222 variant against a broad panel of different prion isolates and further reinforce the argument supporting the use of this variant in breeding programs to control TSEs in goat herds. IMPORTANCE: The objective of this study was to determine the role of the K222 variant of the prion protein (PrP) in the susceptibility/resistance of goats to transmissible spongiform encephalopathies (TSEs). Results showed that transgenic mice expressing the goat K222-PrP polymorphic variant are resistant to scrapie and bovine spongiform encephalopathy (BSE) agents. This protective effect was also observed in heterozygous Q/K222 animals. Therefore, the single amino acid exchange from Q to K at codon 222 of the cellular prion protein provides resistance against TSEs. All the results presented here support the view that the K222 polymorphic variant is a good candidate for selective breeding programs to control and eradicate scrapie in goat herds.
Assuntos
Resistência à Doença/genética , Polimorfismo Genético , Proteínas PrPC/genética , Scrapie/genética , Animais , Bovinos , Códon , Encefalopatia Espongiforme Bovina/genética , Encefalopatia Espongiforme Bovina/mortalidade , Encefalopatia Espongiforme Bovina/transmissão , Feminino , Expressão Gênica , Predisposição Genética para Doença , Genótipo , Cabras , Masculino , Camundongos , Camundongos Transgênicos , Proteínas PrPC/metabolismo , Scrapie/mortalidade , Scrapie/transmissão , OvinosRESUMO
We describe an atypical neuropathological phenotype of sporadic Creutzfeldt-Jakob disease in a 76-year-old man. The clinical symptoms were characterized by progressive dementia, gait ataxia, rigidity and urinary incontinence. The disease duration was 6 weeks. MRI did not show prominent atrophy or hyperintensities in cortical areas, striatum or thalamus. Biomarker examination of the cerebrospinal fluid deviated from that seen in pure Alzheimer's disease. Triphasic waves in the EEG were detected only later in the disease course, while 14-3-3 assay was positive. PRNP genotyping revealed methionine homozygosity (MM) at codon 129. Neuropathology showed classical CJD changes corresponding to the MM type 1 cases. However, a striking feature was the presence of abundant kuru-type plaques in the white matter. This rare morphology was associated with neuropathological signs of intranuclear inclusion body disease and advanced stage of argyrophilic grain disease. These alterations did not show correlation with each other, thus seemed to develop independently. This case further highlights the complexity of neuropathological alterations in the ageing brain.
Assuntos
Encéfalo/patologia , Síndrome de Creutzfeldt-Jakob/patologia , Encefalopatia Espongiforme Bovina/patologia , Kuru/patologia , Tauopatias/patologia , Substância Branca/patologia , Idoso , Síndrome de Creutzfeldt-Jakob/complicações , Síndrome de Creutzfeldt-Jakob/genética , Encefalopatia Espongiforme Bovina/complicações , Encefalopatia Espongiforme Bovina/genética , Humanos , Corpos de Inclusão Intranuclear/patologia , Kuru/complicações , Masculino , Metionina/genética , Fenótipo , Tauopatias/complicaçõesRESUMO
BACKGROUND: Sheep with prion protein (PrP) gene polymorphisms QQ171 and RQ171 were shown to be susceptible to the prion causing L-type bovine spongiform encephalopathy (L-BSE), although RQ171 sheep specifically propagated a distinctive prion molecular phenotype in their brains, characterized by a high molecular mass protease-resistant PrP fragment (HMM PrPres), distinct from L-BSE in QQ171 sheep. METHODS: The resulting infectious and biological properties of QQ171 and RQ171 ovine L-BSE prions were investigated in transgenic mice expressing either bovine or ovine PrP. RESULTS: In both mouse lines, ovine L-BSE transmitted similarly to cattle-derived L-BSE, with respect to survival periods, histopathology, and biochemical features of PrPres in the brain, as well as splenotropism, clearly differing from ovine classic BSE or from scrapie strain CH1641. Nevertheless and unexpectedly, HMM PrPres was found in the spleen of ovine PrP transgenic mice infected with L-BSE from RQ171 sheep at first passage, reminiscent, in lymphoid tissues only, of the distinct PrPres features found in RQ171 sheep brains. CONCLUSIONS: The L-BSE agent differs from both ovine classic BSE or CH1641 scrapie maintaining its specific strain properties after passage in sheep, although striking PrPres molecular changes could be found in RQ171 sheep and in the spleen of ovine PrP transgenic mice.
Assuntos
Encefalopatia Espongiforme Bovina/classificação , Encefalopatia Espongiforme Bovina/genética , Príons/genética , Príons/metabolismo , Animais , Química Encefálica , Bovinos , Encefalopatia Espongiforme Bovina/metabolismo , Encefalopatia Espongiforme Bovina/patologia , Predisposição Genética para Doença , Camundongos , Camundongos Transgênicos , Fenótipo , Príons/química , OvinosRESUMO
BACKGROUND: Prion diseases are fatal neurodegenerative disorders whose pathogenesis mechanisms are not fully understood. In this context, the analysis of gene expression alterations occurring in prion-infected animals represents a powerful tool that may contribute to unravel the molecular basis of prion diseases and therefore discover novel potential targets for diagnosis and therapeutics. Here we present the first large-scale transcriptional profiling of brains from BSE-infected cynomolgus macaques, which are an excellent model for human prion disorders. RESULTS: The study was conducted using the GeneChip® Rhesus Macaque Genome Array and revealed 300 transcripts with expression changes greater than twofold. Among these, the bioinformatics analysis identified 86 genes with known functions, most of which are involved in cellular development, cell death and survival, lipid homeostasis, and acute phase response signaling. RT-qPCR was performed on selected gene transcripts in order to validate the differential expression in infected animals versus controls. The results obtained with the microarray technology were confirmed and a gene signature was identified. In brief, HBB and HBA2 were down-regulated in infected macaques, whereas TTR, APOC1 and SERPINA3 were up-regulated. CONCLUSIONS: Some genes involved in oxygen or lipid transport and in innate immunity were found to be dysregulated in prion infected macaques. These genes are known to be involved in other neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Our results may facilitate the identification of potential disease biomarkers for many neurodegenerative diseases.