Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut, USA.
Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.
J Virol. 2020 Mar 31;94(8). doi: 10.1128/JVI.01967-19.
Given that the Ebola virus (EBOV) infects a wide array of organs and cells yet displays a relative lack of neurotropism, we asked whether a chimeric vesicular stomatitis virus (VSV) expressing the EBOV glycoprotein (GP) might selectively target brain tumors. The mucin-like domain (MLD) of the EBOV GP may enhance virus immune system evasion. Here, we compared chimeric VSVs in which EBOV GP replaces the VSV glycoprotein, thereby reducing the neurotoxicity associated with wild-type VSV. A chimeric VSV expressing the full-length EBOV GP (VSV-EBOV) containing the MLD was substantially more effective and safer than a parallel construct with an EBOV GP lacking the MLD (VSV-EBOVΔMLD). One-step growth, reverse transcription-quantitative PCR, and Western blotting assessments showed that VSV-EBOVΔMLD produced substantially more progeny faster than VSV-EBOV. Using immunodeficient SCID mice, we focused on targeting human brain tumors with these VSV-EBOVs. Similar to the findings of our previous study in which we used an attenuated VSV-EBOV with no MLD that expressed green fluorescent protein (GFP) (VSV-EBOVΔMLD-GFP), VSV-EBOVΔMLD without GFP targeted glioma but yielded only a modest extension of survival. In contrast, VSV-EBOV containing the MLD showed substantially better targeting and elimination of brain tumors after intravenous delivery and increased the survival of brain tumor-bearing mice. Despite the apparent destruction of most tumor cells by VSV-EBOVΔMLD, the virus remained active within the SCID mouse brain and showed widespread infection of normal brain cells. In contrast, VSV-EBOV eliminated the tumors and showed relatively little infection of normal brain cells. Parallel experiments with direct intracranial virus infection generated similar results. Neither VSV-EBOV nor VSV-EBOVΔMLD showed substantive infection of the brains of normal immunocompetent mice. The Ebola virus glycoprotein contains a mucin-like domain which may play a role in immune evasion. Chimeric vesicular stomatitis viruses with the EBOV glycoprotein substituted for the VSV glycoprotein show greater safety and efficacy in targeting brain tumors in immunodeficient mice when the MLD was expressed within the EBOV glycoprotein than when EBOV lacked the mucin-like domain.
鉴于埃博拉病毒 (EBOV) 感染广泛的器官和细胞，但表现出相对缺乏嗜神经性，我们想知道表达埃博拉病毒糖蛋白 (GP) 的嵌合水疱性口炎病毒 (VSV) 是否可能选择性地靶向脑肿瘤。EBOV GP 的粘蛋白样结构域 (MLD) 可能增强病毒对免疫系统的逃避。在这里，我们比较了嵌合 VSV，其中 EBOV GP 取代了 VSV 糖蛋白，从而降低了与野生型 VSV 相关的神经毒性。表达全长 EBOV GP (VSV-EBOV) 的嵌合 VSV 包含 MLD，比具有缺失 MLD 的平行构建体 (VSV-EBOVΔMLD) 更有效和更安全。一步生长、逆转录定量 PCR 和 Western blot 评估表明，VSV-EBOVΔMLD 比 VSV-EBOV 更快地产生更多的后代。使用免疫缺陷性 SCID 小鼠，我们专注于用这些 VSV-EBOV 靶向人类脑肿瘤。与我们之前的研究结果类似，我们使用了一种没有 MLD 的减毒 VSV-EBOV，该 VSV-EBOV 表达绿色荧光蛋白 (GFP) (VSV-EBOVΔMLD-GFP)，VSV-EBOVΔMLD 没有 GFP 靶向神经胶质瘤，但仅延长了生存时间。相比之下，含有 MLD 的 VSV-EBOV 在静脉给药后表现出更好的靶向和消除脑肿瘤的能力，并增加了脑肿瘤荷瘤小鼠的存活时间。尽管 VSV-EBOVΔMLD 明显破坏了大多数肿瘤细胞，但病毒仍然在 SCID 小鼠大脑中保持活跃，并显示出对正常脑细胞的广泛感染。相比之下，VSV-EBOV 消除了肿瘤，并显示出对正常脑细胞的相对较少感染。直接颅内病毒感染的平行实验产生了类似的结果。VSV-EBOV 和 VSV-EBOVΔMLD 都没有实质性地感染正常免疫功能小鼠的大脑。埃博拉病毒糖蛋白含有粘蛋白样结构域，可能在免疫逃避中起作用。嵌合水疱性口炎病毒用埃博拉病毒糖蛋白取代 VSV 糖蛋白，当 EBOV 糖蛋白表达 MLD 时，比 EBOV 缺乏粘蛋白样结构域时，在免疫缺陷小鼠中靶向脑肿瘤的安全性和疗效更高。
