Disruption of the Opal Stop Codon Attenuates Chikungunya Virus-Induced Arthritis and Pathology.
Disruption of the Opal Stop Codon Attenuates Chikungunya Virus-Induced Arthritis and Pathology.
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DOI：
10.1128/mbio.01456-17
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发表时间：
2017-11-14
期刊：
影响因子：
6.4
通讯作者：
Heise MT
中科院分区：
文献类型：
--
作者：
Jones JE;Long KM;Whitmore AC;Sanders W;Thurlow LR;Brown JA;Morrison CR;Vincent H;Peck KM;Browning C;Moorman N;Lim JK;Heise MT
基孔肯雅病毒 (CHIKV) 是一种蚊媒甲病毒，在过去十年中导致数次严重的急性和慢性关节炎和关节痛爆发。其中包括最近在加勒比海岛屿和美洲爆发的疫情，导致超过 100 万例病毒性关节痛病例。尽管 CHIKV 对全球健康产生重大影响，但促进 CHIKV 诱发疾病的病毒决定因素尚不完全清楚。大多数 CHIKV 毒株在病毒 nsP3 基因末端含有保守的蛋白石终止密码子。然而，编码精氨酸密码子代替蛋白石终止密码子的 CHIKV 菌株已被描述，并且对来自加勒比海的 CHIKV 分离株的深度测序分析鉴定出该菌株中的精氨酸和蛋白石变体。因此，我们假设引入精氨酸突变代替蛋白石终止密码子可能会影响 CHIKV 毒力。我们通过将精氨酸突变引入来自斯里兰卡的 CHIKV 毒株的充分表征的感染性克隆中来对此进行测试，并将该病毒命名为 Opal524R。这种突变不会损害病毒在体外或体内的复制动力学。尽管如此，Opal524R 病毒在受感染小鼠的脚和脚踝内引起的肿胀、炎症和损伤明显减轻。此外，我们观察到与亲本菌株相比，促炎细胞因子和趋化因子的诱导延迟，以及 CD4+ T 细胞和 NK 细胞募集减少。因此，蛋白石终止密码子在 CHIKV 发病机制中发挥着重要作用，与对病毒复制的影响无关。基孔肯雅病毒（CHIKV）是一种蚊媒甲病毒，可引起病毒性关节痛的严重爆发。对 CHIKV 和其他甲病毒的研究表明，nsP3 中的蛋白石终止密码子高度保守。然而，CHIKV 和其他甲病毒的某些毒株的蛋白石终止密码子含有突变。这些突变改变了哺乳动物和蚊子宿主中相关甲病毒的毒力。在这里，我们报告了最近在加勒比海岛屿爆发的 CHIKV 毒株的临床分离株，其中含有编码蛋白石终止密码子或精氨酸突变的病毒混合物。将蛋白石终止密码子突变为精氨酸残基可减轻小鼠模型中 CHIKV 诱导的疾病。与感染含蛋白石的亲代病毒相比，感染精氨酸突变体会导致有限的肿胀和炎症，并抑制病理学免疫介质（包括 CD4+ T 细胞和 NK 细胞）的募集。我们认为蛋白石终止密码子在严重 CHIKV 疾病的诱导中起着重要作用。
Chikungunya virus (CHIKV) is a mosquito-borne alphavirus responsible for several significant outbreaks of debilitating acute and chronic arthritis and arthralgia over the past decade. These include a recent outbreak in the Caribbean islands and the Americas that caused more than 1 million cases of viral arthralgia. Despite the major impact of CHIKV on global health, viral determinants that promote CHIKV-induced disease are incompletely understood. Most CHIKV strains contain a conserved opal stop codon at the end of the viral nsP3 gene. However, CHIKV strains that encode an arginine codon in place of the opal stop codon have been described, and deep-sequencing analysis of a CHIKV isolate from the Caribbean identified both arginine and opal variants within this strain. Therefore, we hypothesized that the introduction of the arginine mutation in place of the opal termination codon may influence CHIKV virulence. We tested this by introducing the arginine mutation into a well-characterized infectious clone of a CHIKV strain from Sri Lanka and designated this virus Opal524R. This mutation did not impair viral replication kinetics in vitro or in vivo. Despite this, the Opal524R virus induced significantly less swelling, inflammation, and damage within the feet and ankles of infected mice. Further, we observed delayed induction of proinflammatory cytokines and chemokines, as well as reduced CD4+ T cell and NK cell recruitment compared to those in the parental strain. Therefore, the opal termination codon plays an important role in CHIKV pathogenesis, independently of effects on viral replication. Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes significant outbreaks of viral arthralgia. Studies with CHIKV and other alphaviruses demonstrated that the opal termination codon within nsP3 is highly conserved. However, some strains of CHIKV and other alphaviruses contain mutations in the opal termination codon. These mutations alter the virulence of related alphaviruses in mammalian and mosquito hosts. Here, we report that a clinical isolate of a CHIKV strain from the recent outbreak in the Caribbean islands contains a mixture of viruses encoding either the opal termination codon or an arginine mutation. Mutating the opal stop codon to an arginine residue attenuates CHIKV-induced disease in a mouse model. Compared to infection with the opal-containing parental virus, infection with the arginine mutant causes limited swelling and inflammation, as well as dampened recruitment of immune mediators of pathology, including CD4+ T cells and NK cells. We propose that the opal termination codon plays an essential role in the induction of severe CHIKV disease.