RESUMEN
PURPOSE: Creutzfeldt-Jakob disease (CJD) primarily affects the brain. This study was conducted to assess the possible involvement of the eye in sporadic and variant CJD by testing for the presence of the disease-associated, protease-resistant isoform of the prion protein (PrP(Sc)) in ocular tissue. METHODS: Human eyes from donors with CJD and non-prion neurodegenerative disease control eyes were studied. In situ hybridization and Western blot analysis were used to determine the normal pattern of cellular prion protein (PrP(C)) expression. Western blot analysis and immunohistochemistry were then used to determine the localization, abundance, and isotype of PrP(Sc) in eyes in CJD. RESULTS: PrP(C) was expressed in the nuclear layers of the retina. In both the sporadic and variant forms of CJD, PrP(Sc) accumulated throughout the synaptic layers of the retina. The levels of PrP(Sc) found in the retina were comparable with those found in the brain. Lower levels of PrP(Sc) could be found in the optic nerve, but no PrP(Sc) was detectable in other ocular tissues. The glycoform ratio of PrP(Sc) in the retina did not correspond to that found in the brain. CONCLUSIONS: Presumptive centrifugal spread of PrP(Sc) from the brain through the optic nerve occurs in two major types of CJD. PrP(Sc) is a marker of CJD infectivity. Given that routine decontamination may not remove PrP(Sc) from surgical instruments, a careful risk assessment should be made of possible iatrogenic spread of sporadic and variant CJD after surgery to the retina or optic nerve.
Asunto(s)
Síndrome de Creutzfeldt-Jakob/metabolismo , Proteínas PrPSc/metabolismo , Retina/metabolismo , Enfermedades de la Retina/metabolismo , Western Blotting , Encéfalo/metabolismo , Síndrome de Creutzfeldt-Jakob/patología , Síndrome de Creutzfeldt-Jakob/transmisión , Humanos , Técnicas para Inmunoenzimas , Hibridación in Situ , Nervio Óptico/metabolismo , Retina/patologíaRESUMEN
The cellular prion protein (PrPC) from different species can be reproducibly expressed in Xenopus oocytes following injection of in vitro transcribed mRNAs. The level of PrPC accumulation increases with the amount of RNA injected and with the duration of incubation. PrPC expressed in oocytes is similar in size and abundance to PrPC protein in mouse brain and >100 ng of PrPC is expressed per oocyte allowing complete experiments to be carried out in single living cells. The protein is glycosylated, fully protease sensitive and expressed on the cell surface. Xenopus oocytes therefore provide a useful model system for the study of prion proteins and their associated disease processes.
Asunto(s)
Oocitos/efectos de los fármacos , Proteínas PrPC/biosíntesis , ARN Mensajero/farmacología , Xenopus laevis/metabolismo , Animales , Cricetinae , Relación Dosis-Respuesta a Droga , Endopeptidasas/metabolismo , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/fisiología , Glicosilación/efectos de los fármacos , Glicoproteínas de Membrana/efectos de los fármacos , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Ratones , Modelos Animales , Peso Molecular , Oocitos/citología , Oocitos/metabolismo , Proteínas PrPC/genética , Transporte de Proteínas/efectos de los fármacos , Transporte de Proteínas/fisiología , ARN Mensajero/genética , Temperatura , Xenopus laevis/anatomía & histología , Xenopus laevis/genéticaRESUMEN
The prion protein (PrP) and Doppel (Dpl) have many structural and biochemical properties in common, leading to the suggestion that the lack of an obvious phenotype in PrP-deficient mice maybe because of compensation by Dpl. To test this hypothesis and also investigate the function of Dpl we have generated Prnd(-/-) and Prnp(-/-)/Prnd(-/-) mouse lines. Both develop normally and display an identical male sterility phenotype that differs from that reported for another Prnd(-/-) mouse line. Sperm from both our mutant lines were present at normal concentrations, had normal motility, and no morphological abnormalities. Despite only rarely fertilizing oocytes in vivo, because of an inability to perform the acrosome reaction, mutant sperm were capable of fertilization in vitro, albeit at reduced rates compared to wild type. Elevated levels of oxidative DNA damage were found in both types of mutant sperm and resulting embryos failed at an early stage. Therefore we found no evidence that Dpl compensates for the loss of PrP function in mutant mouse lines, but it does have an important anti-oxidant function necessary for sperm integrity and male fertility.
Asunto(s)
Daño del ADN/genética , Fertilización In Vitro , Infertilidad Masculina/genética , Priones/genética , Reacción Acrosómica , Animales , Secuencia de Bases , Cromatina/patología , Cromatina/ultraestructura , Cartilla de ADN , Epidídimo , Proteínas Ligadas a GPI , Masculino , Ratones , Ratones Noqueados , Reacción en Cadena de la Polimerasa , Priones/fisiología , Motilidad Espermática , Espermatozoides/citología , Espermatozoides/patología , Espermatozoides/fisiologíaRESUMEN
The function of the normal conformational isoform of prion protein, PrP(C), remains unclear although lines of research have suggested a role in the cellular response to oxidative stress. Here we investigate the expression of PrP(C) in hypoxic brain tissues to examine whether PrP(C) is in part regulated by neuronal stress. Cases of adult cerebral ischemia and perinatal hypoxic-ischemic injury in humans were compared with control tissues. PrP(C) immunoreactivity accumulates within neuronal processes in the penumbra of hypoxic damage in adult brain, and within neuronal soma in cases of perinatal hypoxic-ischemic injury, and in situ hybridization analysis suggests an up-regulation of PrP mRNA during hypoxia. Rodents also showed an accumulation of PrP(C) in neuronal soma within the penumbra of ischemic lesions. Furthermore, the infarct size in PrP-null mice was significantly greater than in the wild type, supporting the proposed role for PrP(C) in the neuroprotective adaptive cellular response to hypoxic injury.