PML Body Component Sp100A Restricts Wild-Type Herpes Simplex Virus 1 Infection
PML Body Component Sp100A Restricts Wild-Type Herpes Simplex Virus 1 Infection
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PML 身体成分 Sp100A 限制野生型单纯疱疹病毒 1 感染
DOI：
10.1128/jvi.00279-22
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发表时间：
2022-04-27
影响因子：
5.4
通讯作者：
Xu, Pei
中科院分区：
文献类型：
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作者：
Ma, Yilei;Li, Jingjing;Xu, Pei
以前的研究表明，PML体组分Sp100蛋白在生产性感染期间立即被细胞核中HSV-1的ICP 0靶向。Sp100（speckled protein 100 kDa）是早幼粒细胞白血病（promyelocytic leukemia，PML）细胞核结构的组成部分，在介导内源性免疫和先天性免疫中发挥重要作用。Sp100基因编码四种亚型，在细胞和病毒基因的转录调控中具有不同的作用。由于Sp100是感染细胞蛋白0（ICP 0）的主要核内靶点，ICP 0是由单纯疱疹病毒1（HSV-1）编码的立即早期E3连接酶，以前的研究试图分析单个Sp100变体在HSV-1感染期间的功能，大多避免使用野生型病毒。因此，Sp100在HSV-1自然感染下的作用仍有待阐明。在这里，我们重新评估了四种Sp100亚型的抗病毒能力，在感染过程中的非突变的HSV-1，详细研究了Sp100蛋白的分子行为，并揭示了以下有趣的观察。首先，Sp100亚型A（Sp100 A）抑制野生型HSV-1在HEp-2、Sp100（-/-）和PML-/-细胞中的增殖。第二，内源性Sp100位于细胞核和细胞质中。在HSV-1感染期间，在同一亚细胞区室中检测到ICP 0后，核Sp100水平急剧下降，但胞质Sp100保持稳定。第三，转染的Sp100 A表现出类似于内源性Sp100的亚细胞定位，并与内源性胞质Sp100的蛋白质大小相匹配。第四，HSV-1感染诱导内源性Sp100和异位表达Sp100 A的分泌增加，其与细胞外囊泡（EV）共纯化，但不与感染性病毒粒子共纯化。第五，分泌细胞中的Sp100 A水平与EV中的Sp100 A水平呈正相关，EV相关的Sp100 A限制了受体细胞中的HSV-1。以前的研究表明，PML体成分Sp100蛋白在生产性感染期间立即被细胞核中HSV-1的ICP 0靶向。因此，使用缺乏ICP 0的突变病毒或在不存在感染的情况下进行了调查Sp100同种型与HSV-1相互作用的广泛研究。Sp100变体在自然HSV-1感染中的作用仍然模糊。在这里，我们报告说，Sp100 A有效地和独立地抑制野生型HSV-1和HSV-1感染期间，胞质Sp100保持稳定，并越来越多地分泌到细胞外空间，与EV。此外，分泌细胞中的Sp100 A水平与其在EV中的水平以及这些EV在受体细胞中的抗HSV-1效力正相关。综上所述，本研究提示Sp100 A在野生型HSV-1感染过程中具有积极的抗病毒作用，并揭示了Sp100 A通过细胞外通讯限制HSV-1的新机制。
Previous studies show that the PML body component Sp100 protein is immediately targeted by ICP0 of HSV-1 in the nucleus during productive infection. Therefore, extensive studies investigating the interplay of Sp100 isoforms with HSV-1 were conducted using a mutant virus lacking ICP0 or in the absence of infection.Sp100 (speckled protein 100 kDa) is a constituent component of nuclear structure PML (promyelocytic leukemia) bodies, playing important roles in mediating intrinsic and innate immunity. The Sp100 gene encodes four isoforms with distinct roles in the transcriptional regulation of both cellular and viral genes. Since Sp100 is a primary intranuclear target of infected-cell protein 0 (ICP0), an immediate early E3 ligase encoded by herpes simplex virus 1 (HSV-1), previous investigations attempting to analyze the functions of individual Sp100 variants during HSV-1 infection mostly avoided using a wild-type virus. Therefore, the role of Sp100 under natural infection by HSV-1 remains to be clarified. Here, we reappraised the antiviral capacity of four Sp100 isoforms during infection by a nonmutated HSV-1, examined the molecular behavior of the Sp100 protein in detail, and revealed the following intriguing observations. First, Sp100 isoform A (Sp100A) inhibited wild-type HSV-1 propagation in HEp-2, Sp100(-/-), and PML-/- cells. Second, endogenous Sp100 is located in both the nucleus and the cytoplasm. During HSV-1 infection, the nuclear Sp100 level decreased drastically upon the detection of ICP0 in the same subcellular compartment, but cytosolic Sp100 remained stable. Third, transfected Sp100A showed subcellular localizations similar to those of endogenous Sp100 and matched the protein size of endogenous cytosolic Sp100. Fourth, HSV-1 infection induced increased secretion of endogenous Sp100 and ectopically expressed Sp100A, which copurified with extracellular vesicles (EVs) but not infectious virions. Fifth, the Sp100A level in secreting cells positively correlated with its level in EVs, and EV-associated Sp100A restricted HSV-1 in recipient cells. IMPORTANCE Previous studies show that the PML body component Sp100 protein is immediately targeted by ICP0 of HSV-1 in the nucleus during productive infection. Therefore, extensive studies investigating the interplay of Sp100 isoforms with HSV-1 were conducted using a mutant virus lacking ICP0 or in the absence of infection. The role of Sp100 variants during natural HSV-1 infection remains blurry. Here, we report that Sp100A potently and independently inhibited wild-type HSV-1 and that during HSV-1 infection, cytosolic Sp100 remained stable and was increasingly secreted into the extracellular space, in association with EVs. Furthermore, the Sp100A level in secreting cells positively correlated with its level in EVs and the anti-HSV-1 potency of these EVs in recipient cells. In summary, this study implies an active antiviral role of Sp100A during wild-type HSV-1 infection and reveals a novel mechanism of Sp100A to restrict HSV-1 through extracellular communications.