IFIH1 (MDA5) is required for innate immune detection of intron-containing RNA expressed from the HIV-1 provirus.
IFIH1 (MDA5) is required for innate immune detection of intron-containing RNA expressed from the HIV-1 provirus.
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IFIH1 (MDA5) 是先天免疫检测 HIV-1 原病毒表达的含内含子 RNA 所必需的。
DOI：
10.1101/2023.11.17.567619
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Luban,Jeremy
中科院分区：
文献类型：
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作者：
Guney,MehmetHakan;Nagalekshmi,Karthika;McCauley,SeanMatthew;Carbone,Claudia;Aydemir,Ozkan;Luban,Jeremy
从HIV-1前病毒表达的含内含子的RNA激活原代人血细胞中的1型干扰素，包括CD 4 +T细胞、巨噬细胞和树突细胞。为了鉴定检测从HIV-1原病毒表达的含内含子RNA所需的先天免疫受体，用靶向人单核细胞衍生的树突细胞中的21个候选基因的短发夹RNA表达慢病毒载体进行功能丧失筛选。在测试的候选基因中，只有XPO 1（CRM 1）、IFIH 1（MDA 5）或MAVS的敲低阻止了干扰素刺激基因ISG 15的激活。IFIH 1蛋白的重要性通过用非靶向IFIH 1编码序列拯救敲低来证明。IFIH 1特异性尼帕病毒V蛋白和IFIH 1反显性2-CARD结构域缺失或磷酸化模拟点突变对HIV-1诱导的ISG 15的抑制表明，IFIH 1（MDA 5）细丝形成、去磷酸化和与MAVS的结合都是响应HIV-1转导的先天免疫激活所需的。由于IFIH 1（MDA 5）和DDX 58（RIG-I）均通过MAVS发出信号，因此通过IFIH 1检测HIV-1 RNA的特异性通过DDX 58敲低对激活无影响的事实得到证明。RNA-Seq显示，树突状细胞中的IFIH 1敲低全面破坏了HIV-1对IFN刺激基因的诱导。最后，通过甲醛交联免疫沉淀法（f-CLIP）发现IFIH 1（MDA 5）对未剪接的HIV-1 RNA的特异性富集超过两个数量级。这些结果表明，IFIH 1是来自HIV-1前病毒的含内含子RNA的先天免疫受体，即使在有效的抗逆转录病毒治疗的情况下，IFIH 1也可能导致HIV-1感染者的慢性炎症。
Intron-containing RNA expressed from the HIV-1 provirus activates type 1 interferon in primary human blood cells, including CD4+T cells, macrophages, and dendritic cells. To identify the innate immune receptor required for detection of intron-containing RNA expressed from the HIV-1 provirus, a loss-of-function screen was performed with short hairpin RNA-expressing lentivectors targeting twenty-one candidate genes in human monocyte-derived dendritic cells. Among the candidate genes tested, only knockdown of XPO1 (CRM1), IFIH1 (MDA5), or MAVS prevented activation of the interferon-stimulated gene ISG15. The importance of IFIH1 protein was demonstrated by rescue of the knockdown with nontargetable IFIH1 coding sequence. Inhibition of HIV-1-induced ISG15 by the IFIH1-specific Nipah virus V protein, and by IFIH1-transdominant 2-CARD domain-deletion or phosphomimetic point mutations, indicates that IFIH1 (MDA5) filament formation, dephosphorylation, and association with MAVS are all required for innate immune activation in response to HIV-1 transduction. Since both IFIH1 (MDA5) and DDX58 (RIG-I) signal via MAVS, the specificity of HIV-1 RNA detection by IFIH1 was demonstrated by the fact that DDX58 knockdown had no effect on activation. RNA-Seq showed that IFIH1 knockdown in dendritic cells globally disrupted the induction of IFN-stimulated genes by HIV-1. Finally, specific enrichment of unspliced HIV-1 RNA by IFIH1 (MDA5), over two orders of magnitude, was revealed by formaldehyde cross-linking immunoprecipitation (f-CLIP). These results demonstrate that IFIH1 is the innate immune receptor for intron-containing RNA from the HIV-1 provirus and that IFIH1 potentially contributes to chronic inflammation in people living with HIV-1, even in the presence of effective antiretroviral therapy.