Biochemical analysis of abnormal prion protein in the cases with sporadic Creutzfeldt-Jakob disease.

我们可以检查一例日本的散发性克雅氏病(CJD)患者，该患者同时表达了1型和2型抗蛋白酶的普恩蛋白(PrP)。该例的病理特征表现为突触和空泡周围PrP沉积。在22例患者中，仅1例(4.5%)同时存在1型和2型PrP。我们对英国散发性CJD患者进行了PrP分型，发现18例CJD患者中有7例(38.9%)同时存在1型和2型PrP，显著高于日本。正如以前报道的，种族间的遗传差异也被阐明；在所有日本病例中，Pron蛋白基因129密码子的多态性完全由蛋氨酸纯合子组成(100%)，而在英国病例中(55.6%)。虽然不同病例的脑桥核病理分级不同，但其严重程度不受病原菌种类差异的影响，而仅受病程的影响。日本散发性CJD患者PrP类型和临床病理特征的同质性可能部分与种族背景有关。由于日本散发性CJD患者中具有蛋白酶抗性的PrP的生化特性相对同质性，我们试图检测PrP寡聚体，以便根据构象差异对PrP异常进行分类。我们确定了一种替代方法，这将是一种简单且无风险的方法来检测PrP聚集体。建立了以单体形式溶解细胞PrP，以聚集体或低聚物形式溶解异常PrP的最佳条件。因此，我们可以用简单的方法在较短的时间内分离PrP聚集体。最近发现PrP寡聚体比高度聚集的PrP纤维具有更强的感染性和神经毒性。这种简单的PrP寡聚体检测方法可能适合于PrP疾病的实际分析。

We could examine one case with sporadic Creutzfeldt-Jakob disease (CJD) in Japan that expressed co-occurrence of type 1 and type 2 protease-resistant prion protein (PrP). Pathological features of the unique case showed both synaptic and perivacuolar PrP depositions. Coexistence of type 1 and type 2 PrP was observed in only single case (4.5%) among 22 cases examined. We have examined PrP types in sporadic CJD cases in United Kingdom and found that 7 (38.9%) out of 18 cases showed coexistence of type 1 and type 2 PrP, which was significantly higher level than in Japan. Genetic differences among races were also elucidated as reported previously ; codon 129 polymorphism of the prion protein gene consisted entirely of methionin homozygosity in all Japanese cases (100%), in contrast with UK cases (55.6%). Although the pathological grade of pontine nuclei varied among cases, the severity was not affected by the difference of pathogen strain, but merely by the time course of disease progression. Homogeneity of PrP types and clinicopathological features in Japanese sporadic CJD cases may be based on the ethnic background in part.Because the biochemical properties of protease-resistant PrP in Japanese sporadic CJD cases were relatively homogeneous, we tried to detect PrP oligomers so that we could classify the abnormal PrP based on the conformational differences. We determined an alternative method, which would be a simple and riskless procedure to detect PrP aggregates. The optimized condition was established to solubilize cellular PrP as monomers and leave abnormal PrP as aggregates or oligomers. Therefore we could separate PrP aggregates by the simple method in a shorter time. Recently it has been found that PrP oligomers rather than highly aggregated PrP fibrils have more potent infectivity and neurotoxicity. This simple method for PrP oligomer detection may be suitable for practical use for the analysis of prion diseases.