Data Sheet 1_Distinct ZIKV strain signatures and type I IFN modulation reveal a protective role of brain endothelial interferon signaling in vitro and in vivo.pdf

IntroductionZika virus (ZIKV) infection has been associated with neurological syndromes, particularly during outbreaks caused by Asian lineage strains. However, experimental models suggest that African strains may exhibit an equal or more virulent profile. Neuroinvasion by systemic viruses often requires crossing the blood–brain barrier (BBB), which disruption amplifies viral dissemination and neuropathology. Type I interferons (IFNs) are key to restricting ZIKV replication, but their specific role in preserving BBB integrity remains poorly defined.
MethodsHere, we used human brain microvascular endothelial cells (HBMECs) as a simplified BBB model to compare transcriptional responses and IFN modulation following infection with either the African prototype strain ZIKVMR766 or the Asian epidemic strain ZIKVPE243. The role of endothelial cell–mediated IFN responses was further assessed in vivo by intravascular inoculation of mice with endothelial-specific IFNAR depletion using ZIKVMR766.
Results and discussionInfection of HBMEC with ZIKVMR766 triggered a greater number and broader range of differentially expressed genes, especially ones associated with interferon signaling and translational pathways, whereas ZIKVPE243-infected samples clustered closer to non-infected ones. ZIKVMR766 infection also resulted in higher viral titers and faster dissemination across endothelial monolayers. Both strains induced IFN-β expression but suppressed downstream IFN signaling by reducing STAT1 phosphorylation and promoting STAT2 degradation, with these effects being more pronounced for ZIKVMR766. Despite these evasion mechanisms, neutralization assays revealed that endothelial cells-derived IFNs production and response partially restricted viral replication, preserved HBMEC viability, and protected against barrier disruption, with ZIKVPE243 showing greater sensitivity to IFN-β. Importantly, in vivo infection of mice lacking endothelial IFNAR signaling resulted in elevated CNS viral load and increased lethality following ZIKVMR766 infection, underscoring the pivotal role of endothelial IFN responses in viral control, maintenance of BBB integrity, and protection against neuroinvasion.

引言
寨卡病毒（Zika virus, ZIKV）感染与神经系统综合征存在明确关联，尤其在亚洲谱系毒株引发的暴发疫情中更为显著。不过，现有实验模型研究表明，非洲谱系毒株的致病能力可能与亚洲毒株相当，甚至更强。系统性病毒的神经侵袭通常需要跨越血脑屏障（blood–brain barrier, BBB），该屏障的破坏会加剧病毒播散与神经病理损伤。I型干扰素（Type I interferons, IFNs）是抑制寨卡病毒复制的关键因子，但其在维持血脑屏障完整性中的具体作用仍有待阐明。

方法
本研究采用人脑微血管内皮细胞（human brain microvascular endothelial cells, HBMECs）构建简化的血脑屏障模型，对比非洲原型毒株ZIKVMR766与亚洲流行毒株ZIKVPE243感染后，细胞的转录组应答与干扰素调控模式差异。为进一步评估内皮细胞介导的干扰素应答的功能，本研究通过血管内接种ZIKVMR766，对内皮细胞特异性敲除干扰素α/β受体（IFNAR）的小鼠开展体内实验。

结果与讨论
ZIKVMR766感染人脑微血管内皮细胞后，诱导产生的差异表达基因数量更多、覆盖通路更广，尤其是与干扰素信号通路及翻译通路相关的基因；而ZIKVPE243感染的样本转录组聚类结果更贴近未感染对照组。此外，ZIKVMR766感染的内皮细胞中病毒滴度更高，且在单层内皮细胞间的播散速度更快。两种毒株均能诱导干扰素β（IFN-β）的表达，但同时通过降低信号转导与转录激活因子1（STAT1）的磷酸化水平、促进信号转导与转录激活因子2（STAT2）的降解来抑制下游干扰素信号通路，且ZIKVMR766的该抑制效应更为显著。尽管存在上述免疫逃逸机制，中和实验结果显示，内皮细胞产生的干扰素及其介导的应答可部分抑制病毒复制，维持人脑微血管内皮细胞的活力，并避免血脑屏障被破坏；其中ZIKVPE243对IFN-β的敏感性更高。值得注意的是，在内皮细胞IFNAR信号缺失的小鼠中，ZIKVMR766感染后中枢神经系统（central nervous system, CNS）病毒载量升高，小鼠死亡率增加，这进一步证实了内皮细胞干扰素应答在病毒控制、维持血脑屏障完整性以及抵御神经侵袭过程中的关键作用。