AXL分子通过抑制I型干扰素通路促进寨卡病毒感染的机制研究

Infection of pregnant women with Zika virus (ZIKV) can cause infection of the fetal brain, leading to neurological defects including microcephaly. Our previous studies have shown that ZIKV can effectively infect human glial cells, and AXL plays an essential role during ZIKV infection. Genetic ablation of AXL did not block the entry of ZIKV but rather, prevent productive ZIKV replication in infected cells. Type I interferon receptor knockout can effectively rescue viral replication (Nat Microbiol, 2018), indicating that AXL promotes Zika virus infection in astrocytes by antagonizing type I interferon signaling. However, the underlying mechanisms have not been fully elucidated. In this study, we propose to explore two different approaches to unfold the underlying mechanism. First, we will aim to identify the potential synergetic molecule(s) of AXL by using co-immunoprecipitation methods combined with lentiCRISPR-V2 membrane protein library screening platform. Second, we will continue to further explore the molecular mechanism whereby AXL downregulates type I interferon signaling pathway by using transcriptomics analysis and in vitro cell model. Our studies may identify more targets for new drug development or immune intervention.

寨卡病毒（Zika virus，ZIKV）感染孕妇导致胎儿中枢神经系统感染，并引发小头症。我们前期研究表明，ZIKV能够有效感染人神经胶质细胞，且感染依赖于AXL分子的表达。AXL缺失不影响病毒进入神经胶质细胞，但致其不能有效复制。I型干扰素受体敲除能够有效拯救病毒复制（Nat Microbiol,2018），表明AXL分子能通过抑制I型干扰素通路促进ZIKV感染，但机制尚未阐明。本项目将从两个思路入手进一步解析AXL拮抗I型干扰素的机制：一是利用免疫共沉淀技术结合lentiCRISPR-V2膜蛋白库筛选平台，鉴定AXL分子新的协同分子，并验证其协同AXL分子活化的作用；二是通过体外细胞模型结合转录组学分析，在分子层面继续深入探究AXL分子负调控I型干扰素信号通路的分子机制，找到AXL分子信号通路下游作用的靶标及作用机制。这些机制的阐明将为新药与免疫干预技术提供新的可能靶点。

在RNA病毒感染过程中，I型干扰素信号起着关键的抗病毒作用，而病毒如何通过如AXL分子以及其它膜蛋白分子抑制I型干扰素信号通路的机制尚有很多未知。我们前期研究表明，ZIKV能够有效感染人神经胶质细胞，且感染依赖于AXL分子的表达，AXL分子能通过抑制I型干扰素通路促进ZIKV感染。我们近期的研究发现AXL和ACE2分子等参与拮抗I型干扰素信号并研究其分子机制，RNA病毒（包括ZIKV和SARS-CoV-2等）感染能提升ACE2分子的表达，ACE2表达显著抑制I型干扰素的生产和下游应答信号，这些干扰素信号通路抑制分子的作用和作用机理的阐明将为新药与免疫干预技术提供新的可能靶点。

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