The Role of VP1 Amino Acid Residue 145 of Enterovirus 71 in Viral Fitness and Pathogenesis in a Cynomolgus Monkey Model.
The Role of VP1 Amino Acid Residue 145 of Enterovirus 71 in Viral Fitness and Pathogenesis in a Cynomolgus Monkey Model.
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DOI：
10.1371/journal.ppat.1005033
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发表时间：
2015-07
期刊：
影响因子：
6.7
通讯作者：
Shimizu H
中科院分区：
文献类型：
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作者：
Kataoka C;Suzuki T;Kotani O;Iwata-Yoshikawa N;Nagata N;Ami Y;Wakita T;Nishimura Y;Shimizu H
肠道病毒71（EV 71）是手足口病的主要病原体，偶尔会引起严重的神经系统症状。我们鉴定了P-选择素糖蛋白配体-1（PSGL-1）作为EV 71受体，并发现衣壳蛋白VP 1（VP 1 -145）中的氨基酸残基145定义了EV 71的PSGL-1结合（PB）和PSGL-1非结合（non-PB）表型。然而，PSGL-1依赖性EV 71复制在神经发病机制中的作用仍然知之甚少。在这项研究中，我们调查了病毒复制，遗传稳定性，和致病性的PB和非PB株的EV 71食蟹猴模型。分别用在VP 1 -98和VP 1 -145处具有两个氨基酸差异的EV 71、EV 71 -02363-EG和EV 71 -02363-KE菌株的cDNA衍生的PB和非PB菌株静脉内接种猴子。主要在02363-KE接种猴中发现轻度神经系统症状、一过性淋巴细胞减少症和炎性细胞因子反应。在感染的早期阶段，在02363-KE接种猴的临床样品中经常检测到病毒，但在02363-EG接种猴的样品中很少检测到病毒。感染后10天的中枢神经系统（CNS）组织的组织学分析表明，02363-KE诱导的神经病变比02363-EG诱导的更有效。接种02363-EG后，几乎所有在临床样品、CNS和非CNS组织中检测到的EV 71变体在VP 1 -145处具有G至E氨基酸取代，表明VP 1 - 145 E变体的强体内选择性和CNS传播可能以PSGL-1非依赖性方式进行。仅在四只接种02363-EG的猴子中的两只的外周血单核细胞中鉴定出具有VP 1 - 145 G的EV 71变体。因此，VP 1 - 145 E变异体主要负责在非人灵长类动物模型中病毒血症和神经发病机制的发展，进一步表明在EV 71感染个体中，VP 1 -145处的氨基酸多态性在细胞特异性病毒复制、体内适应性和发病机制中的体内参与。最近，已报告了手足口病的大规模爆发，包括主要由肠道病毒71型（EV 71）引起的幼儿致命神经系统病例，特别是在该疾病对公共卫生构成严重威胁的亚太地区。基于EV 71的突变和结构分析，我们鉴定了衣壳蛋白VP 1的氨基酸残基145（VP 1 -145）是EV 71与特异性细胞受体人P-选择素糖蛋白配体-1（PSGL-1）结合的关键分子决定簇。VP 1 -145在EV 71分离株中高度可变，并且已被鉴定为人类和实验小鼠模型中的潜在神经毒力决定因子。为了阐明PSGL-1依赖性复制和发病机制的体内参与，我们在食蟹猴模型中研究了EV 71的PSGL-1结合（PB）和PSGL-1非结合（non-PB）株的病毒复制、遗传稳定性和致病性。静脉接种PB毒株后，发现病毒在VP 1 -145处高度突变，产生的VP 1 - 145 E变体（非PB）可能以PSGL-1非依赖性方式诱导病毒血症和神经发病。VP 1 - 145 G变体仅在来自两只PB接种猴的外周血单核细胞中鉴定。我们的研究为EV 71感染者中病毒、受体和宿主之间的相互作用提供了新的见解。
Enterovirus 71 (EV71), a major causative agent of hand, foot, and mouth disease, occasionally causes severe neurological symptoms. We identified P-selectin glycoprotein ligand-1 (PSGL-1) as an EV71 receptor and found that an amino acid residue 145 in the capsid protein VP1 (VP1-145) defined PSGL-1-binding (PB) and PSGL-1-nonbinding (non-PB) phenotypes of EV71. However, the role of PSGL-1-dependent EV71 replication in neuropathogenesis remains poorly understood. In this study, we investigated viral replication, genetic stability, and the pathogenicity of PB and non-PB strains of EV71 in a cynomolgus monkey model. Monkeys were intravenously inoculated with cDNA-derived PB and non-PB strains of EV71, EV71-02363-EG and EV71-02363-KE strains, respectively, with two amino acid differences at VP1-98 and VP1-145. Mild neurological symptoms, transient lymphocytopenia, and inflammatory cytokine responses, were found predominantly in the 02363-KE-inoculated monkeys. During the early stage of infection, viruses were frequently detected in clinical samples from 02363-KE-inoculated monkeys but rarely in samples from 02363-EG-inoculated monkeys. Histopathological analysis of central nervous system (CNS) tissues at 10 days postinfection revealed that 02363-KE induced neuropathogenesis more efficiently than that induced by 02363-EG. After inoculation with 02363-EG, almost all EV71 variants detected in clinical samples, CNS, and non-CNS tissues, possessed a G to E amino acid substitution at VP1-145, suggesting a strong in vivo selection of VP1-145E variants and CNS spread presumably in a PSGL-1-independent manner. EV71 variants with VP1-145G were identified only in peripheral blood mononuclear cells in two out of four 02363-EG-inoculated monkeys. Thus, VP1-145E variants are mainly responsible for the development of viremia and neuropathogenesis in a non-human primate model, further suggesting the in vivo involvement of amino acid polymorphism at VP1-145 in cell-specific viral replication, in vivo fitness, and pathogenesis in EV71-infected individuals. Recently, large outbreaks of hand, foot, and mouth disease, including fatal neurological cases in young children primarily because of enterovirus 71 (EV71) have been reported, particularly in the Asia Pacific regions where the disease poses a serious threat to public health. Based on mutational and structural analyses of EV71, we identified amino acid residue 145 of the capsid protein VP1 (VP1-145) as a critical molecular determinant for the binding of EV71 to a specific cellular receptor, human P-selectin glycoprotein ligand-1 (PSGL-1). VP1-145 is highly variable among EV71 isolates and has been identified as a potential neurovirulence determinant in humans and experimental mouse models. To elucidate the in vivo involvement of PSGL-1-depentent replication and pathogenesis, we investigated viral replication, genetic stability, and the pathogenicity of the PSGL-1-binding (PB) and PSGL-1-nonbinding (non-PB) strains of EV71 in a cynomolgus monkey model. After the intravenous inoculation with the PB strain, viruses found to be highly mutated at VP1-145 with resultant VP1-145E variants (non-PB) inducing viremia and neuropathogenesis, presumably in a PSGL-1-independent manner. VP1-145G variants were identified only in peripheral blood mononuclear cells from two PB-inoculated monkeys. Our study provides new insights into the interplay between virus, receptors, and host in EV71-infected individuals.