Amyloid fibrils of mammalian prion protein are highly toxic to cultured cells and primary neurons
Amyloid fibrils of mammalian prion protein are highly toxic to cultured cells and primary neurons
复制标题
DOI：
10.1074/jbc.m511174200
复制
发表时间：
2006-05-12
影响因子：
4.8
通讯作者：
Baskakov, IV
中科院分区：
文献类型：
--
作者：
Novitskaya, V;Bocharova, OV;Baskakov, IV
越来越多的证据表明，由各种蛋白质和多肽而不是成熟的淀粉样纤维产生的小的、可溶的寡聚体本身就具有高度的细胞毒性。在这里，我们首次证明了由全长重组哺乳动物PrP(RPrP)产生的成熟淀粉样纤维对培养细胞以及原代海马神经元和小脑神经元具有高度毒性。纤维以时间和剂量依赖的方式诱导细胞凋亡。纤维的毒性作用与由相同蛋白质产生的可溶小β-寡聚体的毒性作用相当。从胰岛素中制备的纤维是无毒的，这表明毒性效应不仅仅是由于纤维形式的高度聚合性质。当内源性PrPC的表达被小干扰RNA下调时，rPrP纤维或β-寡聚体引起的细胞死亡显著减少。与rPrP的β-寡聚体和淀粉样纤维相反，rPrP的单体α-螺旋形式促进了神经元突起的生长和存活。这些研究表明，Prion蛋白的可溶性β-寡聚体和淀粉样纤维都具有内在毒性，并证实了内源性表达的PrPC是介导异常折叠的外部PrP聚集体的毒性所必需的。
A growing body of evidence indicates that small, soluble oligomeric species generated from a variety of proteins and peptides rather than mature amyloid fibrils are inherently highly cytotoxic. Here, we show for the first time that mature amyloid fibrils produced from full- length recombinant mammalian prion protein ( rPrP) were highly toxic to cultured cells and primary hippocampal and cerebella neurons. Fibrils induced apoptotic cell death in a time- and dose- dependent manner. The toxic effect of fibrils was comparable with that exhibited by soluble small beta- oligomers generated from the same protein. Fibrils prepared from insulin were not toxic, suggesting that the toxic effect was not solely due to the highly polymeric nature of the fibrillar form. The cell death caused by rPrP fibrils or beta- oligomers was substantially reduced when expression of endogenous PrPC was down- regulated by small interfering RNAs. In opposition to the beta- oligomer and amyloid fibrils of rPrP, the monomeric alpha- helical form of rPrP stimulated neurite outgrowth and survival of neurons. These studies illustrated that both soluble beta- oligomer and amyloid fibrils of the prion protein are intrinsically toxic and confirmed that endogenously expressed PrPC is required for mediating the toxicity of abnormally folded external PrP aggregates.