Japanese Encephalitis virus (JEV) is a zoonotic flavivirus that is the most significant etiological agent of childhood viral neurological infections. However, no specific antiviral drug is currently available to treat JEV infections. The JEV envelope (E) protein is a class II viral fusion protein that mediates host cell entry, making interference with the interaction between the E protein of JEV and its cognate receptors an attractive strategy for anti-JEV drug development. In this study, we identified a peptide derived from a phage display peptide library against the E protein of JEV, designated P1, that potentially inhibits in vitro and in vivo JEV infections. P1 inhibits JEV infection in BHK-21 cells with 50% inhibitory capacity at a concentration of 35.9 μM. The time-of-addition assay indicates that JEV replication is significantly inhibited during pre-infection and co-infection of P1 with JEV while post-infection treatments with P1 have very little impact on JEV proliferation, showing that P1 inhibits JEV infection at early stages and indicating the potential prophylactic effect of P1. We adapted an in vitro BiFC assay system and demonstrated that P1 interacts with JEV E proteins and blocks their entry into cells. We also evaluated the therapeutic efficacy of P1 in a lethal JEV mouse model exhibiting systemic and brain infections. Interestingly, P1 treatment protected C57BL/6 mice against mortality, markedly reduced the viral loads in blood and brain, and diminished the histopathological lesions in the brain cells. In addition to controlling systemic infection, P1 has a very low level of cytotoxicity and acts in a sequence-specific manner, as scrambled peptide sP1 does not show any antiviral activity. In conclusion, our in vitro and in vivo experimental findings show that P1 possesses antiviral activity against JEV infections, is safe to use, and has potential for further development as an antiviral treatment against JEV infections.

中文翻译：

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噬菌体展示选择的肽在体外和体内对日本脑炎病毒感染的抗病毒活性。

日本脑炎病毒（JEV）是一种人畜共患的黄病毒，是儿童病毒性神经系统感染的最重要病因。但是，目前尚无可用于治疗JEV感染的抗病毒药物。JEV包膜（E）蛋白是II类病毒融合蛋白，可介导宿主细胞进入，使JEV E蛋白与其同源受体之间的相互作用受到干扰，成为抗JEV药物开发的诱人策略。在这项研究中，我们确定了针对JEV E蛋白的噬菌体展示肽文库衍生的肽，命名为P1，该肽可能抑制体内和体外JEV感染。P1以35.9μM的浓度抑制BHK-21细胞中的JEV感染，抑制能力为50％。添加时间分析表明，在P1与JEV的感染前和共感染期间，JEV复制受到明显抑制，而P1的感染后治疗对JEV增殖的影响很小，表明P1在早期抑制JEV感染。并指出P1的潜在预防作用。我们采用了体外BiFC分析系统，并证明P1与JEV E蛋白相互作用并阻止其进入细胞。我们还评估了P1在表现出全身和脑部感染的致死性JEV小鼠模型中的治疗效果。有趣的是，P1处理可保护C57BL / 6小鼠免于死亡，显着减少血液和大脑中的病毒载量，并减少脑细胞的组织病理学损害。除了控制全身感染之外，P1的细胞毒性水平非常低，并且以序列特异性方式发挥作用，因为混乱的肽sP1没有显示任何抗病毒活性。总之，我们的体内和体外实验结果表明，P1具有对抗JEV感染的抗病毒活性，使用安全，并且有可能作为抗JEV感染的抗病毒治疗药物进一步开发。