Remdesivir is active <i>in vitro</i> against tick-borne encephalitis virus and selects for resistance mutations in the viral RNA-dependent RNA polymerase

Tick-borne encephalitis (TBE) is a neurological disease caused by the tick-borne encephalitis virus (TBEV). Despite available vaccines, breakthrough infections occur, some fatal. As no antiviral therapy for TBE is currently approved, this study evaluated the <i>in vitro</i> activity of already licenced remdesivir (RDV) and sofosbuvir (SOF) for possible drug repurposing against TBEV. TBEV was cultured in A549 cells, and the inhibitory effects of RDV (GS-5734), its parent nucleotide GS-441524, and SOF (GS-7977) were assessed. After 78 h, RDV demonstrated significantly lower EC₅₀ values than SOF (0.14 vs. 11 µM) based on TBEV RNA levels measured by RT-qPCR. RDV also had a lower mean EC₅₀ (0.55 µM) compared to GS-441524 and SOF (&gt;8.9 and 13.1 µM, respectively) using crystal violet staining after 5 days. After 11 passages of TBEV in the presence of RDV, emergence of virus with a higher EC₅₀ (1.32 vs. 0.55 µM) was detected with two mutations (L3122F and Y3278F) in NS5, the viral RNA-dependent RNA polymerase (RdRp), and one substitution in envelope (E) protein (E402G). Similarly, SOF resistance appeared after 20 passages, increasing EC₅₀ values (35.5 vs. 10 µM). RDV exhibits potent <i>in vitro</i> antiviral activity against TBEV via specific targeting of the viral RdRp as confirmed by the emergence of resistance-associated double NS5 substitutions <i>in vitro</i> in the presence of RDV. While the potential <i>in vivo</i> implications of the observed RDV resistance remain to be determined, these <i>in vitro</i> data support further assessment of RDV for the treatment of TBEV infection.

蜱传脑炎（Tick-borne encephalitis, TBE）是由蜱传脑炎病毒（Tick-borne encephalitis virus, TBEV）引发的神经系统疾病。尽管已有获批疫苗，但仍会出现突破性感染，部分病例可致命。由于目前尚无针对TBE的获批抗病毒疗法，本研究评估了已上市的瑞德西韦（remdesivir, RDV）与索非布韦（sofosbuvir, SOF）用于抗TBEV的药物重定位潜力。研究将TBEV培养于A549细胞中，并评估了RDV（GS-5734）、其母体核苷酸GS-441524以及SOF（GS-7977）的抑制效果。培养78小时后，基于实时定量荧光PCR（RT-qPCR）检测的TBEV RNA水平，RDV的半数有效浓度（EC₅₀）显著低于SOF（0.14 μM vs. 11 μM）。采用结晶紫染色法培养5天后，相较于GS-441524与SOF（分别>8.9 μM和13.1 μM），RDV的平均半数有效浓度同样更低（0.55 μM）。在RDV存在下对TBEV进行11次传代后，检测到半数有效浓度升高的病毒株（1.32 μM vs. 0.55 μM），该毒株的病毒RNA依赖的RNA聚合酶（RNA-dependent RNA polymerase, RdRp）NS5蛋白存在两处突变（L3122F和Y3278F），包膜（E）蛋白存在一处替换（E402G）。类似地，在20次传代后出现了对SOF的耐药性，其半数有效浓度升高至35.5 μM（初始值为10 μM）。RDV可通过特异性靶向病毒RdRp发挥强效的体外（in vitro）抗TBEV活性，这一点可通过RDV存在下体外培养中出现与耐药相关的NS5双替换突变得到证实。尽管目前仍需明确所观察到的RDV耐药性在体内（in vivo）的潜在影响，但上述体外数据支持进一步评估RDV用于治疗TBEV感染的可行性。

搜集汇总

背景与挑战

背景概述

该数据集研究了瑞德西韦（RDV）对蜱传脑炎病毒（TBEV）的体外抗病毒活性及其耐药性机制。实验结果显示，RDV比索磷布韦（SOF）具有更低的EC50值，表明更强的抑制效果；在RDV压力下，病毒通过RNA依赖性RNA聚合酶（RdRp）的突变产生耐药性。这些发现支持RDV作为潜在TBE治疗药物的进一步评估，为药物再利用提供了体外证据。