PDF(Pubmed)
Abstract：
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 (EC50) = 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.
摘要：
全球重新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爆发有关，并与急性弛缓性脊髓炎有关。然而,对于EV-D68感染仍然缺乏有效的治疗方法.在这项工作中,我们发现宿主Toll样受体7（TLR7）蛋白，作为强大的先天免疫传感器，在响应EV-D68感染时表达选择性升高。随后，我们调查了维沙莫德(GS-9620)的影响，Toll样受体7激动剂，在EV-D68复制上。我们的发现揭示EV-D68感染导致TLR7的mRNA水平增加。用Vesatolimod治疗可显着抑制EV-D68复制[最大有效浓度的一半（EC50）=0.1427µM]，而在杀病毒浓度下不会诱导明显的细胞毒性。尽管Vesatolimod对EV-D68附件的影响有限，病毒进入后抑制RNA复制和病毒蛋白合成。Vesatolimod广泛抑制了循环分离的EV-D68菌株的复制。此外，我们的研究结果表明,Vesatolimod治疗赋予了呼吸道和神经细胞对EV-D68感染的抵抗.总的来说,这些结果为药物开发提供了一种有前景的策略,即通过药理学激活TLR7,选择性地在EV-D68感染的细胞中启动抗病毒状态.重要的抗病毒药物开发的常规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。在这项研究中,基于我们有趣的发现，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，在呼吸细胞中不存在或低水平表达，我们提出了一种潜在的抗病毒方法，利用TLR7激动剂激活EV-D68感染的细胞进入抗病毒防御状态。值得注意的是,我们的研究结果表明,TLR7的药理激活通过TLR7/MyD88依赖性机制有效抑制呼吸道细胞中EV-D68的复制.这项研究不仅提出了一种有前途的药物候选物和针对EV-D68传播的靶标，而且还强调了利用病毒感染诱导的细胞先天免疫反应的独特改变的潜力。在受感染的细胞中选择性地诱导防御状态，同时保护未感染的正常细胞免受与治疗干预相关的潜在不利影响。
