Institute for Immunology, Philipps-University Marburg, 35043 Marburg, Germany.
Institute of Cardiovascular Immunology, University Hospital Bonn, University of Bonn, 53127 Bonn, Germany.
Int J Mol Sci. 2022 Sep 22;23(19):11139. doi: 10.3390/ijms231911139.
Recognition of RNA by receptors of the innate immune system is regulated by various posttranslational modifications. Different single 2'-O-ribose (2'-O-) methylations have been shown to convert TLR7/TLR8 ligands into specific TLR8 ligands, so we investigated whether the position of 2'-O-methylation is crucial for its function. To this end, we designed different 2'-O-methylated RNA oligoribonucleotides (ORN), investigating their immune activity in various cell systems and analyzing degradation under RNase T2 treatment. We found that the 18S rRNA-derived TLR7/8 ligand, RNA63, was differentially digested as a result of 2'-O-methylation, leading to variations in TLR8 and TLR7 inhibition. The suitability of certain 2'-O-methylated RNA63 derivatives as TLR8 agonists was further demonstrated by the fact that other RNA sequences were only weak TLR8 agonists. We were thus able to identify specific 2'-O-methylated RNA derivatives as optimal TLR8 ligands.
先天免疫系统受体对 RNA 的识别受到各种翻译后修饰的调节。已证明不同的单 2'-O-核糖（2'-O-）甲基化将 TLR7/TLR8 配体转化为特定的 TLR8 配体，因此我们研究了 2'-O-甲基化的位置是否对其功能至关重要。为此，我们设计了不同的 2'-O-甲基化 RNA 寡核糖核苷酸（ORN），在各种细胞系统中研究它们的免疫活性，并分析在 RNase T2 处理下的降解情况。我们发现，18S rRNA 衍生的 TLR7/8 配体 RNA63 由于 2'-O-甲基化而被不同程度地消化，导致 TLR8 和 TLR7 抑制的变化。某些 2'-O-甲基化 RNA63 衍生物作为 TLR8 激动剂的适用性进一步证明了其他 RNA 序列仅为弱 TLR8 激动剂。因此，我们能够鉴定出特定的 2'-O-甲基化 RNA 衍生物作为最佳 TLR8 配体。
