Department of Neuropathology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan.
Cell Rep. 2013 Jul 11;4(1):124-34. doi: 10.1016/j.celrep.2013.06.007. Epub 2013 Jul 3.
TDP-43 is the major component protein of ubiquitin-positive inclusions in brains of patients with frontotemporal lobar degeneration (FTLD-TDP) or amyotrophic lateral sclerosis (ALS). Here, we report the characterization of prion-like properties of aggregated TDP-43 prepared from diseased brains. When insoluble TDP-43 from ALS or FTLD-TDP brains was introduced as seeds into SH-SY5Y cells expressing TDP-43, phosphorylated and ubiquitinated TDP-43 was aggregated in a self-templating manner. Immunoblot analyses revealed that the C-terminal fragments of insoluble TDP-43 characteristic of each disease type acted as seeds, inducing seed-dependent aggregation of TDP-43 in these cells. The seeding ability of insoluble TDP-43 was unaffected by proteinase treatment but was abrogated by formic acid. One subtype of TDP-43 aggregate was resistant to boiling treatment. The insoluble fraction from cells harboring TDP-43 aggregates could also trigger intracellular TDP-43 aggregation. These results indicate that insoluble TDP-43 has prion-like properties that may play a role in the progression of TDP-43 proteinopathy.
TDP-43 是额颞叶变性（FTLD-TDP）或肌萎缩性侧索硬化症（ALS）患者大脑中泛素阳性包涵体的主要组成蛋白。在这里，我们报告了从患病大脑中制备的聚集 TDP-43 的类朊病毒特性的特征。当将来自 ALS 或 FTLD-TDP 大脑的不溶性 TDP-43 作为种子引入表达 TDP-43 的 SH-SY5Y 细胞中时，TDP-43 以自我模板的方式发生磷酸化和泛素化聚集。免疫印迹分析表明，每种疾病类型的不溶性 TDP-43 的 C 端片段作为种子起作用，诱导这些细胞中 TDP-43 的种子依赖性聚集。不溶性 TDP-43 的接种能力不受蛋白酶处理的影响，但被甲酸破坏。TDP-43 聚集体的一种亚型对煮沸处理具有抗性。含有 TDP-43 聚集体的细胞的不溶性部分也可以引发细胞内 TDP-43 聚集。这些结果表明，不溶性 TDP-43 具有类朊病毒特性，可能在 TDP-43 蛋白病的进展中起作用。
