PDF(Pubmed)
Abstract：
BACKGROUND: Detection of viruses by host pattern recognition receptors induces the expression of type I interferon (IFN) and IFN-stimulated genes (ISGs), which suppress viral replication. Numerous studies have described HIV-1 as a poor activator of innate immunity in vitro. The exact role that the viral capsid plays in this immune evasion is not fully understood.
RESULTS: To better understand the role of the HIV-1 capsid in sensing we tested the effect of making HIV-1 by co-expressing a truncated Gag that encodes the first 107 amino acids of capsid fused with luciferase or GFP, alongside wild type Gag-pol. We found that unlike wild type HIV-1, viral particles produced with a mixture of wild type and truncated Gag fused to luciferase or GFP induced a potent IFN response in THP-1 cells and macrophages. Innate immune activation by Gag-fusion HIV-1 was dependent on reverse transcription and DNA sensor cGAS, suggesting activation of an IFN response by viral DNA. Further investigation revealed incorporation of the Gag-luciferase/GFP fusion proteins into viral particles that correlated with subtle defects in wild type Gag cleavage and a diminished capacity to saturate restriction factor TRIM5α, likely due to aberrant particle formation. We propose that expression of the Gag fusion protein disturbs the correct cleavage and maturation of wild type Gag, yielding viral particles that are unable to effectively shield viral DNA from detection by innate sensors including cGAS.
CONCLUSIONS: These data highlight the crucial role of capsid in innate evasion and support growing literature that disruption of Gag cleavage and capsid formation induces a viral DNA- and cGAS-dependent innate immune response. Together these data demonstrate a protective role for capsid and suggest that antiviral activity of capsid-targeting antivirals may benefit from enhanced innate and adaptive immunity in vivo.
RESULTS: To better understand the role of the HIV-1 capsid in sensing we tested the effect of making HIV-1 by co-expressing a truncated Gag that encodes the first 107 amino acids of capsid fused with luciferase or GFP, alongside wild type Gag-pol. We found that unlike wild type HIV-1, viral particles produced with a mixture of wild type and truncated Gag fused to luciferase or GFP induced a potent IFN response in THP-1 cells and macrophages. Innate immune activation by Gag-fusion HIV-1 was dependent on reverse transcription and DNA sensor cGAS, suggesting activation of an IFN response by viral DNA. Further investigation revealed incorporation of the Gag-luciferase/GFP fusion proteins into viral particles that correlated with subtle defects in wild type Gag cleavage and a diminished capacity to saturate restriction factor TRIM5α, likely due to aberrant particle formation. We propose that expression of the Gag fusion protein disturbs the correct cleavage and maturation of wild type Gag, yielding viral particles that are unable to effectively shield viral DNA from detection by innate sensors including cGAS.
CONCLUSIONS: These data highlight the crucial role of capsid in innate evasion and support growing literature that disruption of Gag cleavage and capsid formation induces a viral DNA- and cGAS-dependent innate immune response. Together these data demonstrate a protective role for capsid and suggest that antiviral activity of capsid-targeting antivirals may benefit from enhanced innate and adaptive immunity in vivo.
摘要：
背景：通过宿主模式识别受体检测病毒可诱导I型干扰素（IFN）和IFN刺激基因（ISG）的表达，抑制病毒复制。许多研究已经将HIV-1描述为体外先天免疫的不良激活剂。病毒衣壳在这种免疫逃避中的确切作用尚未完全了解。
结果：为了更好地理解HIV-1衣壳在感知中的作用，我们测试了通过共表达截短的Gag来制造HIV-1的效果，该Gag编码衣壳的前107个氨基酸与荧光素酶或GFP融合，和野生型Gag-pol一起.我们发现与野生型HIV-1不同,用野生型和与荧光素酶或GFP融合的截短Gag的混合物产生的病毒颗粒在THP-1细胞和巨噬细胞中诱导有效的IFN应答。Gag融合HIV-1的先天性免疫激活依赖于逆转录和DNA传感器cGAS，提示通过病毒DNA激活IFN应答。进一步的研究表明，将Gag-荧光素酶/GFP融合蛋白掺入病毒颗粒中，该病毒颗粒与野生型Gag裂解中的细微缺陷以及饱和限制因子TRIM5α的能力降低有关，可能是由于异常颗粒形成。我们认为Gag融合蛋白的表达会干扰野生型Gag的正确裂解和成熟，产生的病毒颗粒不能有效地屏蔽病毒DNA从先天传感器，包括cGAS检测。
结论：这些数据强调了衣壳在先天逃避中的关键作用，并支持越来越多的文献，即Gag裂解和衣壳形成的破坏会诱导病毒DNA和cGAS依赖性先天免疫应答。这些数据一起证明了衣壳的保护作用，并表明衣壳靶向抗病毒药物的抗病毒活性可能受益于体内先天和适应性免疫的增强。
结果：为了更好地理解HIV-1衣壳在感知中的作用，我们测试了通过共表达截短的Gag来制造HIV-1的效果，该Gag编码衣壳的前107个氨基酸与荧光素酶或GFP融合，和野生型Gag-pol一起.我们发现与野生型HIV-1不同,用野生型和与荧光素酶或GFP融合的截短Gag的混合物产生的病毒颗粒在THP-1细胞和巨噬细胞中诱导有效的IFN应答。Gag融合HIV-1的先天性免疫激活依赖于逆转录和DNA传感器cGAS，提示通过病毒DNA激活IFN应答。进一步的研究表明，将Gag-荧光素酶/GFP融合蛋白掺入病毒颗粒中，该病毒颗粒与野生型Gag裂解中的细微缺陷以及饱和限制因子TRIM5α的能力降低有关，可能是由于异常颗粒形成。我们认为Gag融合蛋白的表达会干扰野生型Gag的正确裂解和成熟，产生的病毒颗粒不能有效地屏蔽病毒DNA从先天传感器，包括cGAS检测。
结论：这些数据强调了衣壳在先天逃避中的关键作用，并支持越来越多的文献，即Gag裂解和衣壳形成的破坏会诱导病毒DNA和cGAS依赖性先天免疫应答。这些数据一起证明了衣壳的保护作用，并表明衣壳靶向抗病毒药物的抗病毒活性可能受益于体内先天和适应性免疫的增强。
