Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, China.
Key Laboratory of Virology of Guangdong province, Jinan University, Guangzhou, China.
Theranostics. 2021 Sep 21;11(19):9623-9651. doi: 10.7150/thno.64880. eCollection 2021.
Microglia are the primary cellular source of type I interferons (I-IFNs) in the brain upon neurotropic virus infection. Although the I-IFN-based antiviral innate immune response is crucial for eliminating viruses, overproduction led to immune disorders. Therefore, the relatively long-lasting I-IFNs must be precisely controlled, but the regulatory mechanism for the innate antiviral response in microglia remains largely unknown. Long non-coding RNAs (lncRNAs) are being recognized as crucial factors in numerous diseases, but their regulatory roles in the innate antiviral response in microglia are undefined. The high-throughput RNA sequencing was performed to obtain differentially expressed lncRNAs (DELs) in primary microglia infected with or without the neurotropic herpes simplex virus type 1 (HSV-1). We selected four DELs ranked in the top 15 in basic level and their fold change induced by HSV-1, i.e., FPKM/FPKM.We subsequently found a key lncRNA affecting the innate antiviral response of microglia significantly. We next used dual-luciferase reporter assays, bioinformatical tools, and truncation mutants of both lncRNA and targeted proteins to elucidate the downstream and upstream mechanism of action of lncRNA. Further, we established microglia-specific knock-in (KI) mice to investigate the role of lncRNA . We identified a long intergenic non-coding RNA, linc-AhRA, involved in regulating the innate antiviral response in murine microglia. is activated by aryl hydrocarbon receptor (AhR) and restricts I-IFN production in microglia upon neurotropic herpesvirus infection and innate immune stimulation. Mechanistically, linc-AhRA binds to both tripartite motif-containing 27 (TRIM27) and TANK-binding kinase 1 (TBK1) through its conserved 117nt fragment as a molecular scaffold to enhance TRIM27-TBK1 interaction. This interaction facilitates the TRIM27-mediated ubiquitination of TBK1 and results in ubiquitin-proteasome-dependent degradation of TBK1. Consequently, linc-AhRA suppresses I-IFN production through facilitating TBK1 degradation and limits the microglial innate immune response against neurotropic herpesvirus infection. Microglia-specific KI of linc-AhRA mice shows a weakened antiviral immune response upon neurotropic herpesvirus challenge due to a reduction of TBK1 in microglia. Our findings indicate that linc-AhRA is a negative regulator of I-IFN production in microglia to avoid excessive autoimmune responses. These findings uncover a previously unappreciated role for lncRNA conserved fragments in the innate antiviral response, providing a strong foundation for developing nucleotide drugs based on conserved functional fragments within lncRNAs.
小胶质细胞是神经亲和性病毒感染后大脑中 I 型干扰素 (I-IFN) 的主要细胞来源。虽然基于 I-IFN 的抗病毒先天免疫反应对于消除病毒至关重要，但过度产生会导致免疫紊乱。因此，相对持久的 I-IFN 必须得到精确控制，但小胶质细胞中先天抗病毒反应的调节机制在很大程度上仍不清楚。长非编码 RNA (lncRNA) 被认为是许多疾病的关键因素，但它们在小胶质细胞先天抗病毒反应中的调节作用尚未确定。通过高通量 RNA 测序获得了感染或未感染神经亲和性单纯疱疹病毒 1 (HSV-1) 的原代小胶质细胞中差异表达的 lncRNA (DEL)。我们选择了在基础水平上排名前 15 位的四个 DEL，以及它们被 HSV-1 诱导的表达倍数变化，即 FPKM/FPKM。随后，我们发现了一个显著影响小胶质细胞先天抗病毒反应的关键 lncRNA。接下来，我们使用双荧光素酶报告基因检测、生物信息学工具和 lncRNA 及其靶向蛋白的截断突变体来阐明 lncRNA 的下游和上游作用机制。此外，我们建立了小胶质细胞特异性敲入 (KI) 小鼠来研究 lncRNA 的作用。我们鉴定了一个长的基因间非编码 RNA，linc-AhRA，它参与调节小鼠小胶质细胞中的先天抗病毒反应。它通过芳香烃受体 (AhR) 激活，并在神经亲和性疱疹病毒感染和先天免疫刺激时限制小胶质细胞中 I-IFN 的产生。在机制上，linc-AhRA 通过其保守的 117nt 片段作为分子支架与三部分结构域包含蛋白 27 (TRIM27) 和 TANK 结合激酶 1 (TBK1) 结合，从而增强 TRIM27-TBK1 相互作用。这种相互作用促进了 TRIM27 介导的 TBK1 泛素化，并导致 TBK1 的泛素蛋白酶体依赖性降解。因此，linc-AhRA 通过促进 TBK1 降解来抑制 I-IFN 的产生，并限制小胶质细胞对神经亲和性疱疹病毒感染的先天免疫反应。由于小胶质细胞中 TBK1 的减少，linc-AhRA 特异性 KI 小鼠在神经亲和性疱疹病毒挑战下表现出较弱的抗病毒免疫反应。我们的研究结果表明，linc-AhRA 是小胶质细胞中 I-IFN 产生的负调节剂，以避免过度的自身免疫反应。这些发现揭示了 lncRNA 保守片段在先天抗病毒反应中的先前未被认识的作用，为基于 lncRNA 内保守功能片段开发核苷酸药物提供了坚实的基础。
