中药余甘子活性成分PGG抗单纯疱疹病毒I型的作用机制研究

Infection by herpes simplex virus (HSV) is a global public health problem. Although acyclovir (ACV) and related nucleoside analogs are valuable drugs for the treatment of infection and the suppression of dissemination, HSV remains highly prevalent worldwide. The emergence of resistance to ACV has also created an obstacle for the treatment of HSV-infected immunocompromised patients and highlights the need for new, safe and effective antiviral agents. Natural products, particularly the traditional Chinese medicines, which provided various novel drug leads, are known to be an important source of anti-HSV agents. Here we will investigate the underlying mechanism of anti-herpes simplex virus type 1 activity of pentagalloylglucose (PGG) from Phyllanthus emblica Linn. Our previous works found that PGG inhibited HSV-1-induced destruction of cytoskeleton integrity which is related to the reduction of F-actin and of G-actin, and blocked HSV-1 capsids egress from nucleus to cytoplasm. Besides, PGG can downregulate Cofilin 1 and inhibit HSV-1-induced rearrangements of actin cytoskeleton which is important for infectivity. Thus, to analyse the relationships between host cell cytoskeleton, especially the protein Cofilin 1, and anti-HSV activity of PGG, a better mechanistic investigation paradigm may arise.

单纯疱疹病毒（HSV）是重要的人类致病病毒，针对目前临床治疗药物单一及不断出现的耐药现象，申请者以中药余甘子活性成分PGG为研究对象，探索其抗病毒的分子机制。在我们的前期工作中，首次发现PGG抑制核质边缘化和核骨架减少从而抑制病毒粒子出核；蛋白质组学研究和Western-blot检测发现PGG下调细胞骨架蛋白Cofilin1。因此，我们推测PGG的抗病毒作用与其对细胞骨架微丝系统的调控作用存在一定相关性，并通过体内、外实验继续探讨PGG对HSV-1病毒进/出细胞核的影响以及对细胞骨架蛋白尤其是Cofilin1的影响，为同类中药的抗病毒机制研究提供参考。

本项目以PGG为先导化合物研究了其抗HSV-1病毒作用，PGG显著抑制HSV-1标准病毒株及临床耐药株对细胞的感染，可直接杀灭病毒，在病毒吸附、穿刺、入核组装、释放等过程均具有显著效果。PGG影响病毒入核、组装、释放过程与细胞骨架蛋白F-actin、cofilin-1、tubulin和病毒衣壳蛋白UL18、UL38密切相关。病毒组装需要在核内完成，PGG能直接抑制病毒衣壳蛋白的表达和定位，影响病毒衣壳蛋白之间的相互作用，从而阻止病毒形成完整衣壳；同时我们证实了病毒衣壳蛋白的入核需要细胞骨架蛋白的协助，PGG通过调控细胞骨架蛋白的表达及活化，阻止病毒衣壳蛋白入核过程。PGG通过阻止病毒衣壳蛋白入核、抑制病毒衣壳蛋白间的相互作用，最终阻止病毒形成成熟的病毒颗粒。同时PGG可以诱导细胞产生自噬来抗病毒，其机制是通过负调控mTOR信号通路来实现。病毒衣壳蛋白UL18是PGG重要作用靶点之一。通过构建UL18基因敲除病毒株，进一步体内研究UL18基因缺失对病毒感染过程中的影响，为开发新型抗HSV-1病毒药物及新型HSV-1病毒疫苗奠定基础。