Institute of Neuropathology, Zürich, Switzerland.
PLoS Pathog. 2012;8(11):e1002985. doi: 10.1371/journal.ppat.1002985. Epub 2012 Nov 1.
Prions cause neurodegeneration in vivo, yet prion-infected cultured cells do not show cytotoxicity. This has hampered mechanistic studies of prion-induced neurodegeneration. Here we report that prion-infected cultured organotypic cerebellar slices (COCS) experienced progressive spongiform neurodegeneration closely reproducing prion disease, with three different prion strains giving rise to three distinct patterns of prion protein deposition. Neurodegeneration did not occur when PrP was genetically removed from neurons, and a comprehensive pharmacological screen indicated that neurodegeneration was abrogated by compounds known to antagonize prion replication. Prion infection of COCS and mice led to enhanced fodrin cleavage, suggesting the involvement of calpains or caspases in pathogenesis. Accordingly, neurotoxicity and fodrin cleavage were prevented by calpain inhibitors but not by caspase inhibitors, whereas prion replication proceeded unimpeded. Hence calpain inhibition can uncouple prion replication from its neurotoxic sequelae. These data validate COCS as a powerful model system that faithfully reproduces most morphological hallmarks of prion infections. The exquisite accessibility of COCS to pharmacological manipulations was instrumental in recognizing the role of calpains in neurotoxicity, and significantly extends the collection of tools necessary for rigorously dissecting prion pathogenesis.
朊病毒在体内引起神经退行性变，但感染朊病毒的培养细胞没有表现出细胞毒性。这阻碍了对朊病毒诱导的神经退行性变的机制研究。在这里，我们报告说，感染朊病毒的培养型小脑切片（COCS）经历了进行性海绵状神经退行性变，与朊病毒病密切相关，三种不同的朊病毒株导致三种不同的朊病毒蛋白沉积模式。当从神经元中遗传去除 PrP 时，不会发生神经退行性变，并且全面的药理学筛选表明，已知能够拮抗朊病毒复制的化合物可消除神经退行性变。COCS 和小鼠的朊病毒感染导致 fodrin 裂解增强，表明钙蛋白酶或半胱天冬酶参与发病机制。因此，钙蛋白酶抑制剂可预防神经毒性和 fodrin 裂解，但半胱天冬酶抑制剂不能预防，而朊病毒复制不受阻碍。因此，钙蛋白酶抑制可以将朊病毒复制与其神经毒性后果分离。这些数据验证了 COCS 是一种强大的模型系统，可忠实地再现朊病毒感染的大多数形态学特征。COCS 对药理学处理的极高可及性对于认识钙蛋白酶在神经毒性中的作用至关重要，并大大扩展了严格剖析朊病毒发病机制所需的工具集。
