Li Huili, Huang Yuehan, Yang Qingran, Zhang Zhe, Shen Siyu, Guo Haoran, Wei Wei
Institute of Virology and AIDS Research, First Hospital, Jilin University, Changchun, Jilin, China.
Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, Institute of Translational Medicine, First Hospital, Jilin University, Changchun, Jilin, China.
J Virol. 2024 Jun 13;98(6):e0043424. doi: 10.1128/jvi.00434-24. Epub 2024 May 1.
The globally reemerging respiratory pathogen enterovirus D68 (EV-D68) is implicated in outbreaks of severe respiratory illness and associated with acute flaccid myelitis. However, there remains a lack of effective treatments for EV-D68 infection. In this work, we found that the host Toll-like receptor 7 (TLR7) proteins, which function as powerful innate immune sensors, were selectively elevated in expression in response to EV-D68 infection. Subsequently, we investigated the impact of Vesatolimod (GS-9620), a Toll-like receptor 7 agonist, on EV-D68 replication. Our findings revealed that EV-D68 infection resulted in increased mRNA levels of TLR7. Treatment with Vesatolimod significantly inhibited EV-D68 replication [half maximal effective concentration (EC) = 0.1427 µM] without inducing significant cytotoxicity at virucidal concentrations. Although Vesatolimod exhibited limited impact on EV-D68 attachment, it suppressed RNA replication and viral protein synthesis after virus entry. Vesatolimod broadly inhibited the replication of circulating isolated strains of EV-D68. Furthermore, our findings demonstrated that treatment with Vesatolimod conferred resistance to both respiratory and neural cells against EV-D68 infection. Overall, these results present a promising strategy for drug development by pharmacologically activating TLR7 to initiate an antiviral state in EV-D68-infected cells selectively.IMPORTANCEConventional strategies for antiviral drug development primarily focus on directly targeting viral proteases or key components, as well as host proteins involved in viral replication. In this study, based on our intriguing discovery that enterovirus D68 (EV-D68) infection specifically upregulates the expression of immune sensor Toll-like receptor 7 (TLR7) protein, which is either absent or expressed at low levels in respiratory cells, we propose a potential antiviral approach utilizing TLR7 agonists to activate EV-D68-infected cells into an anti-viral defense state. Notably, our findings demonstrate that pharmacological activation of TLR7 effectively suppresses EV-D68 replication in respiratory tract cells through a TLR7/MyD88-dependent mechanism. This study not only presents a promising drug candidate and target against EV-D68 dissemination but also highlights the potential to exploit unique alterations in cellular innate immune responses induced by viral infections, selectively inducing a defensive state in infected cells while safeguarding uninfected normal cells from potential adverse effects associated with therapeutic interventions.
全球再度出现的呼吸道病原体肠道病毒D68（EV-D68）与严重呼吸道疾病的暴发有关，并与急性弛缓性脊髓炎相关。然而，针对EV-D68感染仍缺乏有效的治疗方法。在本研究中，我们发现作为强大的固有免疫传感器发挥作用的宿主Toll样受体7（TLR7）蛋白在受到EV-D68感染时表达选择性升高。随后，我们研究了Toll样受体7激动剂维萨特利莫德（Vesatolimod，GS-9620）对EV-D68复制的影响。我们的研究结果显示，EV-D68感染导致TLR7的mRNA水平升高。用维萨特利莫德治疗可显著抑制EV-D68复制[半数最大有效浓度（EC）=0.1427µM]，且在杀病毒浓度下不会诱导明显的细胞毒性。尽管维萨特利莫德对EV-D68的附着影响有限，但它可抑制病毒进入后的RNA复制和病毒蛋白合成。维萨特利莫德广泛抑制EV-D68流行分离株的复制。此外，我们的研究结果表明，用维萨特利莫德治疗可使呼吸道和神经细胞对EV-D68感染产生抗性。总体而言，这些结果提出了一种有前景的药物开发策略，即通过药理学激活TLR7以在EV-D68感染的细胞中选择性地启动抗病毒状态。
重要性
抗病毒药物开发的传统策略主要集中在直接靶向病毒蛋白酶或关键成分以及参与病毒复制的宿主蛋白。在本研究中，基于我们有趣的发现，即肠道病毒D68（EV-D68）感染特异性上调免疫传感器Toll样受体7（TLR7）蛋白的表达，而该蛋白在呼吸道细胞中不存在或低水平表达，我们提出了一种利用TLR7激动剂将EV-D68感染的细胞激活至抗病毒防御状态的潜在抗病毒方法。值得注意的是，我们的研究结果表明，TLR7的药理学激活通过TLR7/髓样分化因子88（MyD88）依赖性机制有效抑制呼吸道细胞中的EV-D68复制。本研究不仅提出了一种有前景的针对EV-D68传播的候选药物和靶点，还突出了利用病毒感染诱导的细胞固有免疫反应中的独特变化的潜力，在保护未感染的正常细胞免受治疗干预相关潜在不良影响的同时，选择性地在感染细胞中诱导防御状态。
