Institute of Advanced Energy, Kyoto University, Kyoto, 611-0011, Japan.
Graduate School of Energy Science, Kyoto University, Kyoto, 611-0011, Japan.
Sci Rep. 2020 Mar 18;10(1):4934. doi: 10.1038/s41598-020-61966-4.
Prion diseases comprise a fatal neuropathy caused by the conversion of prion protein from a cellular (PrP) to a pathological (PrP) isoform. Previously, we obtained an RNA aptamer, r(GGAGGAGGAGGA) (R12), that folds into a unique G-quadruplex. The R12 homodimer binds to a PrP molecule, inhibiting PrP-to-PrP conversion. Here, we developed a new RNA aptamer, r(GGAGGAGGAGGAGGAGGAGGAGGA) (R24), where two R12s are tandemly connected. The 50% inhibitory concentration for the formation of PrP (IC) of R24 in scrapie-infected cell lines was ca. 100 nM, i.e., much lower than that of R12 by two orders. Except for some antibodies, R24 exhibited the lowest recorded IC and the highest anti-prion activity. We also developed a related aptamer, r(GGAGGAGGAGGA-A-GGAGGAGGAGGA) (R12-A-R12), IC being ca. 500 nM. The structure of a single R12-A-R12 molecule determined by NMR resembled that of the R12 homodimer. The quadruplex structure of either R24 or R12-A-R12 is unimolecular, and therefore the structure could be stably formed when they are administered to a prion-infected cell culture. This may be the reason they can exert high anti-prion activity.
朊病毒病是一种致命的神经病变，由朊病毒蛋白从细胞型（PrPC）转化为病理性（PrPSc）异构体引起。此前，我们获得了一种 RNA 适体 r(GGAGGAGGAGGA)（R12），它折叠成独特的 G-四链体。R12 同源二聚体与 PrP 分子结合，抑制 PrP 向 PrPSc 的转化。在此，我们开发了一种新的 RNA 适体 r(GGAGGAGGAGGAGGAGGAGGAGGA)（R24），其中两个 R12 串联连接。R24 在感染瘙痒病的细胞系中形成 PrP 的 50%抑制浓度（IC）约为 100 nM，即比 R12 低两个数量级。除了一些抗体外，R24 表现出记录到的最低 IC 和最高抗朊病毒活性。我们还开发了一种相关的适体 r(GGAGGAGGAGGA-A-GGAGGAGGAGGA)（R12-A-R12），IC 约为 500 nM。通过 NMR 确定的单个 R12-A-R12 分子的结构类似于 R12 同源二聚体的结构。R24 或 R12-A-R12 的四链体结构都是单分子的，因此当它们被施用于感染朊病毒的细胞培养物时，可以稳定形成结构。这可能是它们能够发挥高抗朊病毒活性的原因。
