Physiological and pathological functions of a novel prion-like protein, PrPLP/Dpl.

新型朊病毒样蛋白 PrPLP/Dpl 的生理和病理功能。

基本信息

批准号：
13470065
负责人：
KATAMINE Shigeru
金额：
$ 9.15万
依托单位：
Nagasaki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13470065/
关键词：
prion diseases prion protein prion-like protein gene-knockout mice neurodegeneration 海綿状変性

项目摘要

Certain lines of mice devoid of prion protein (PrP), such as Ngsk Prnp^<0/0>, exhibit late-onset ataxia due to Purkinje cell degeneration, which is rescued by a transgene encoding PrP. In these mice, PrP-like protein, PrPLP/Dpl, is ectopically expressed by neurons including Purkinje cells and glial cells. To explore mechanisms of the neurodegeneration, two types of transgenic (tg) mice expressing PrPLP/Dpl in all neurons, tg(N-PrPLPIDpI), or only Purkinje cells, tg(P-PrPLP/Dpl), were generated and subsequently backcrossed with non-ataxic Zrch I Prnp^<0/0> mice to eliminate the Prnp alleles. In contrast to the tg mice with the Prnp^<+/+> background, never showing neurological abnormalities, not only tg(N-PrPLP/Dpl) but also, tg(P-PrPLP/Dpl) mice with the Prnp^<0/0> alleles developed Purkinje cell degeneration after incubation periods inversely correlated to the expression levels of PrPLP/Dpl. Moreover, some of the tg mice hemizygous for Prnp allele (Prnp^<0+>) also succumbed to the dise … More ase but much later than those carrying the Prnp^<0/0> alleles. These results indicated that PrPLP/Dpl ectopically expressed by Purkinje cells itself executes a does-dependent deleterious effect on the cells, and that a stoichiometric antagonistic interaction between PrP and PrPLP/Dpl is crucially involved in the neurodegeneration. We next introduced five types of PrP transgenes including heterologous hamster and two mouse/hamster chimeric genes as well as two mutants, each of which encoded PrP lacking residues 23-88 (MHM2.del23-88) or with E199K substitution (Mo.E199K), into Ngsk Prnp^<0/0> mice. Only MHM2.de123-88 failed to rescue from the Purkinje cell death. Little difference was observed in pathology and onset of ataxia between Ngsk Prnp^<0/0> and MHM2.de123-88/Ngsk Prnp^<0/0>. No detergent-insoluble PrPLP/Dpl was detectable in the CNS of Ngsk Prnp^<0/0> even after the onset of ataxia. Our findings provide evidence that the N-terminal residues 23-88 of PrP containing the unique octapeptide-repeat region is crucial for preventing Purkinje cell death in the Prnp^<0/0> mice expressing PrPLP/Dpl in the neuron. Less

某些缺乏朊病毒蛋白(PrP)的小鼠品系，例如Ngsk Prnp^<0/0>，由于浦肯野细胞变性而表现出迟发性共济失调，而编码PrP的转基因在这些小鼠中可以挽救这种现象。 PrPLP/Dpl 蛋白由浦肯野细胞和神经胶质细胞等神经元异位表达。为了探索神经变性的机制，两种类型的转基因 (tg) 小鼠表达了这种蛋白。生成所有神经元中的 PrPLP/Dpl tg(N-PrPLPIDpI) 或仅浦肯野细胞 tg(P-PrPLP/Dpl)，并随后与非共济失调 Zrch I Prnp^<0/0> 小鼠回交以消除Prnp 等位基因与具有 Prnp^<+/+> 背景的 tg 小鼠相反，不仅从未表现出神经系统异常。 tg(N-PrPLP/Dpl) 以及具有 Prnp^<0/0> 等位基因的 tg(P-PrPLP/Dpl) 小鼠在潜伏期后发生浦肯野细胞变性，与 PrPLP/Dpl 的表达水平呈负相关。一些 Prnp 等位基因 (Prnp^<0+>) 半合子的 tg 小鼠也死于这种疾病……更多但比携带 Prnp^<0/0> 等位基因的细胞晚得多。这些结果表明，浦肯野细胞异位表达的 PrPLP/Dpl 本身对细胞产生剂量依赖性有害作用，并且 PrP 和 PrPLP 之间存在化学计量拮抗相互作用。 /Dpl 在神经变性中起着至关重要的作用，接下来我们引入了五种类型的 PrP 转基因，包括异源仓鼠和两种小鼠/仓鼠嵌合基因以及两种。突变体，每个编码缺少残基 23-88 (MHM2.del23-88) 或具有 E199K 取代 (Mo.E199K) 的 PrP，进入 Ngsk Prnp^<0/0> 小鼠中，只有 MHM2.de123-88 未能从小鼠中拯救出来。 Ngsk Prnp^<0/0> 和 Ngsk Prnp^<0/0> 之间的浦肯野细胞死亡在病理学和共济失调发作方面几乎没有观察到差异。 MHM2.de123-88/Ngsk Prnp^<0/0> 即使在共济失调发作后，在 Ngsk Prnp^<0/0> 的 CNS 中也未检测到洗涤剂不溶性 PrPLP/Dpl。 - PrP 的末端残基 23-88 含有独特的八肽重复区域，对于防止浦肯野细胞死亡至关重要Prnp^<0/0> 小鼠在神经元中表达 PrPLP/Dpl 较少。