细菌脂多糖对肠道病毒71型感染影响的初步研究

肠道病毒71型(enterovirus 71, EV71)感染常导致婴幼儿手足口病(hand, foot and mouth disease, HFMD),细菌脂多糖(lipopolysaccharide, LPS)在多种肠道病毒感染过程中起重要作用。本研究旨在探讨细菌LPS对EV71感染的影响。将EV71与LPS共孵育,测定病毒被热处理后残留病毒的活力,以及病毒感染过程中病毒基因拷贝数的变化。结果显示,热处理后病毒活力逐渐丧失,而经LPS处理的病毒活力丧失的速度减缓,且残留病毒活力与LPS浓度呈正相关;LPS处理后的病毒在黏附、侵入、胞内复制及释放过程中基因拷贝数较对照组均降低;免疫印迹分析表明LPS与抗VP1单克隆抗体可竞争性结合EV71,且粪便中的EV71可被抗大肠埃希菌抗体识别。上述结果提示,LPS可增强EV71热稳定性,抑制EV71感染过程,且LPS可能与EV71结合。     

Myristoylation of EV71 VP4 is Essential for Infectivity and Interaction with Membrane Structure

Virologica Sinica - The Enterovirus 71 (EV71) VP4 is co-translationally linked to myristic acid at its amino-terminal glycine residue. However, the role of this myristoylation in the EV71 life...     

Animal models of enterovirus 71 infection: applications and limitations

Human enterovirus 71 (EV71) has emerged as a neuroinvasive virus that is responsible for several outbreaks in the Asia-Pacific region over the past 15 years. Appropriate animal models are needed to understand EV71 neuropathogenesis better and to facilitate the development of effective vaccines and drugs. Non-human primate models have been used to characterize and evaluate the neurovirulence of EV71 after the early outbreaks in late 1990s. However, these models were not suitable for assessing the neurovirulence level of the virus and were associated with ethical and economic difficulties in terms of broad application. Several strategies have been applied to develop mouse models of EV71 infection, including strategies that employ virus adaption and immunodeficient hosts. Although these mouse models do not closely mimic human disease, they have been applied to determine the pathogenesis of and treatment and prevention of the disease. EV71 receptor-transgenic mouse models have recently been developed and have significantly advanced our understanding of the biological features of the virus and the host-parasite interactions. Overall, each of these models has advantages and disadvantages, and these models are differentially suited for studies of EV71 pathogenesis and/or the pre-clinical testing of antiviral drugs and vaccines. In this paper, we review the characteristics, applications and limitation of these EV71 animal models, including non-human primate and mouse models.     

肠道病毒71型感染动物模型的应用与局限

肠道病毒71型(enterovirus 71,EV71)是一种被忽视的热带传染病——手足口病的主要病原体之一,过去15年在亚太地区引起了多次手足口病暴发。由于脊髓灰质炎病毒的有效控制,EV71已成为最重要的嗜神经肠道病毒,其严重的神经系统并发症威胁着儿童健康。合适的动物模型可帮助更好地了解EV71神经致病机制,并有利于开发有效的疫苗和治疗药物。本文就EV71已建立的3类主要动物模型(非人灵长类动物模型、小鼠适应性模型及转基因小鼠模型)的特征、应用与局限进行综述。     

EV71病毒中和表位和诺如病毒P结构域嵌合蛋白的原核表达

目的:构建肠道病毒71型(Enterovirus71,EV71)的线性中和抗原表位与诺如病毒P结构域融合基因的重组质粒,在大肠杆菌中表达诺如病毒P结构域与EV71中和抗原表位的嵌合蛋白。方法:根据已报道的3个EV71线性中和抗原表位的氨基酸序列,按大肠杆菌密码子表达使用的偏好性优化和设计各线性中和抗原表位的核苷酸序列,将这些表位以单个或不同的组合克隆至含诺如病毒P结构域和GST标签的质粒中,经测序确认后,分别转化到E.coli BL21(DE3)感受态细胞中,通过IPTG诱导融合蛋白表达。用GST融合蛋白纯化磁珠对融合蛋白进行纯化,最后通过免疫印迹法确认融合蛋白的表达及嵌合蛋白的抗原性。结果:测序结果表明,成功地构建了含EV71病毒3个单表位和4个串联中和抗原表位的诺如病毒P结构域重组质粒,而且这7个含线性中和抗原表位的嵌合蛋白在大肠杆菌中都以可溶形式得到了表达。免疫印迹分析表达蛋白的抗原性结果表明,表达的嵌合蛋白都能与抗诺如病毒P结构域抗血清反应。除了含单表位的SP55和SP28嵌合蛋白外,其它的嵌合蛋白均能与抗EV71病毒的抗血清反应。结论:成功地在大肠杆菌中表达了诺如病毒P结构域和EV71病毒中和抗原表位的嵌合蛋白,且具有抗原性,这为诺如病毒和EV71病毒的二价疫苗及检测方法的研发奠定了基础。     

A comparison of the biological characteristics of EV71 C4 subtypes from different epidemic strains

The comparative analysis of the biological characterization and the genetic background study of EV71 circulating strains is commonly recognized as basic work necessary for development of an effective EV71 vaccine. In this study, we sequenced five EV71 circulating strains, isolated from Fuyang, Hefei, Kunming and Shenzhen city of China and named them FY-23, FY-22, H44, K9 and S1 respectively. The sequence alignment demonstrated their genotypes be C4. The genetic distance of the VP1 gene from these isolates suggested that they were highly co-related with genetic identity similar to other previously reported EV71 strains in China. Additionally, these strains were identified to display some obvious proliferation dynamics and plaque morphology when propagated in Vero cells. However, a distinctive difference in pathogenic ability in neonatal mice was found. Some differences in cross neutralization test &; immunogenic analysis were also found. All these results are related to the biological characterization of circulating EV71 strains in China and aid in the development of an EV71 vaccine in the future.     

A Comparison of the Biological Characteristics of EV71 C4 Subtypes from Different Epidemic Strains

The comparative analysis of the biological characterization and the genetic background study of EV71 circulating strains is commonly recognized as basic work necessary for development of an effective EV71 vaccine. In this study, we sequenced five EV71 circulating strains, isolated from Fuyang, Hefei, Kunming and Shenzhen city of China and named them FY-23, FY-22, H44, K9 and S1 respectively. The sequence alignment demonstrated their genotypes be C4. The genetic distance of the VP1 gene from these isolates s...     

Generation of neutralizing monoclonal antibodies against Enterovirus 71 using synthetic peptides

Enterovirus 71 (EV71) has led to recent outbreaks of hand, foot and mouth disease (HFMD) in China, resulting in high mortality. In this study, several monoclonal antibodies were generated by immunizing mice with two synthetic peptides, SP55 and SP70, containing amino acids 163-177 and 208-222 of VP1. The specificities of the anti-EV71 peptide monoclonal antibodies were confirmed by Western blot analysis and immunocytochemistry against EV71 virus. Most importantly, we have identified a monoclonal antibody, clone 22A12, which shows strong neutralizing activity against EV71 in an in vitro neutralization assay. Because there is no vaccine available and treatment is very limited, mouse anti-EV71 monoclonal antibody, clone 22A12, could be a promising candidate to be humanized and used for treatment of EV71 infection.     

EV71 infection correlates with viral IgG preexisting at pharyngolaryngeal mucosa in children

Enterovirus 71(EV71) infection causes severe central nervous system damage, particularly for children under the age of 5 years old, which remains a major public health burden worldwide. Clinical data released that children may be repeatedly infected by different members in enterovirus and get even worsen. Mucosa, especially epithelium of alimentary canal, was considered the primary site of EV71 infection. It has been elusive whether the preexsiting viral antibody in mucosa plays a role in EV71 infection. To answer this question, we respectively measured viral antibody response and EV71 RNA copy number of one hundred throat swab specimens from clinically confirmed EV71-infected children. The results released that low-level of mucosal Ig G antibody against EV71 broadly existed in young population. More importantly, it further elucidated that the children with mucosal preexsiting EV71 Ig G were prone to be infected, which suggested a former viral Ig G mediated enhancement of viral infection in vivo.     

细胞膜转运分子ABCC3和SLC7A7在肠道病毒A71型感染中作用的初步研究

肠道病毒A71型(enterovirus A71,EV-A71)是导致手足口病(hand-foot-mouth disease,HFMD)的主要病原体之一,目前对其治疗尚无特异高效的抗病毒药物.研究表明,细胞膜转运相关分子参与病毒的入侵、复制以及感染性子代病毒颗粒的释放.为寻找宿主中可有效抑制EV-A71感染的细胞膜转...     

SILAC‐based quantitative proteomic analysis of secretome of Marc‐145 cells infected with porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of PRRS, which causes severe reproductive failure in sows, respiratory disease in young and growing pigs, and enormous economic losses to the global swine industry. In this study, SILAC combined with MS/MS was used to quantitatively identify the secretory proteins differentially expressed in PRRSV‐infected Marc‐145 cells compared with mock‐infected controls. In total, we identified 204 secretory proteins showing significant differences in infected cells (163 upregulated, 41 downregulated). Intensive bioinformatic analysis of secretome data revealed that PRRSV infection strongly activated nonclassical protein secretion, especially vesicle‐mediated release of exosomal proteins, including different danger‐associated molecular pattern molecules and the majority of secreted proteins involved in protein binding and transport, regulation of response to stimulus, metabolic processes, and immune responses. According to the functional proteins analysis, we speculate that proteins functioning in binding, transport, and the immune response are exploited by PRRSV to facilitate virus replication and immune evasion. Our study for the first time analyzes the secretory protein profile of PRRSV‐infected Marc‐145 cells and provides valuable insight into the host response to PRRSV infection.     

Study of monocyte membrane proteome perturbation during lipopolysaccharide‐induced tolerance using iTRAQ‐based quantitative proteomic approach

Human monocytes' exposure to low‐level lipopolysaccharide (LPS) induces temporary monocytic insensitivity to subsequent LPS challenge. The underlying mechanism of this phenomenon could have important clinical utilities in preventing and/or treating severe infections. In this study, we used an iTRAQ‐based quantitative proteomic approach to comprehensively characterize the membrane proteomes of monocytes before and after LPS exposure. We identified a total of 1651 proteins, of which 53.6% were membrane proteins. Ninety‐four percent of the proteins were quantified and 255 proteins were shown to be tightly regulated by LPS. Subcellular location analysis revealed organelle‐specific response to LPS exposure: more than 90% of identified mitochondrial membrane proteins were significant downregulated, whereas the majority of proteins from other organelles such as ER, Golgi and ribosome were upregulated. Moreover, we found that the expression of most receptors potentially involved in LPS signal pathway (CD14, toll‐like receptor 4, CD11/CD18 complex) were substantially decreased, while the expression of molecules involved in LPS neutralization were enhanced after LPS challenge. Together, these findings could be of significance in understanding the mechanism of LPS tolerance and provide values for designing new approaches for regulating monocytic responses in sepsis patients.     

A proteomics approach to the cell-surface interactome using the enzyme-mediated activation of radical sources reaction

We previously reported a simple method to analyze the interaction of cell-surface molecules in living cells. This method termed enzyme-mediated activation of radical sources (EMARS) is featured by radical formation of the labeling reagent by horseradish peroxidase (HRP). Herein, we propose an approach to the cell-surface molecular interactome by using combination of this EMARS reaction and MS-based proteomics techniques. In the current study, we employed a novel labeling reagent, fluorescein-conjugated arylazide. The fluorescein-tagged proteins resulting from the EMARS reaction were directly detected in the electrophoresis gels with a fluorescence image analyzer. These products were also purified and concentrated by immunoaffinity chromatography with anti-fluorescein antibody-immobilized resins. The purified fluorescein-tagged proteins were subsequently subjected to an MS-based proteomics analysis. Analysis using HRP-conjugated cholera toxin subunit B, which recognizes a lipid raft marker, ganglioside GM1, revealed 30 membrane and secreted proteins that were candidates for the cell-surface molecules coclustering with GM1. The proposed approach will provide a clue to study functional molecular interactions in a variety of biological events on the cell surface.     

2008～2010年河南省人肠道病毒71型基因特征和重组分析

对河南省2008～2010年河南省人肠道病毒71型进行基因特征及重组特点研究。对河南省2008～2010年分离的5株肠道病毒EV71型构建VP1序列系统进化树并分析其全基因组序列的重组特点。VP1序列系统进化分析显示2008～2010年河南株均属于C4基因型的C4a亚群,Bootscan分析和5’NCR、P1、P2、P3区的进化树证实C4基因型在2A～2B处存在EV71的B基因型和C基因型的型内重组及在3B～3C处存在EV71的B基因型和CA16/G-10间的型间重组。2008～2010年河南EV71分离株为C4基因型的C4a亚群,与2004年以来的中国大陆优势株流行趋势完全一致,EV71C4基因型存在基因型内和型间双重组现象。     

Chronic high glucose induced INS‐1β cell mitochondrial dysfunction: A comparative mitochondrial proteome with SILAC

As glucose‐stimulated insulin secretion of pancreatic β cell is triggered and promoted by the metabolic messengers derived from mitochondria, mitochondria take a central stage in the normal function of β cells. β cells in diabetics were chronically exposed to hyperglycemia stimulation, which have been reported to exert deleterious effects on β‐cell mitochondria. However, the mechanism of the toxic effects of hyperglycemia on β‐cell mitochondria was not clear. In this study, we characterized the biological functional changes of rat INS‐1β cells and their mitochondria with chronic exposure to hyperglycemia and created a research model of chronic hyperglycemia‐induced dysfunctional β cells with damaged mitochondria. Then, SILAC‐based quantitative proteomic approach was used to compare the mitochondrial protein expression from high glucose treated INS‐1β cells and control cells. The expression of some mitochondrial proteins was found with significant changes. Functional classification revealed most of these proteins were related with oxidative phosphorylation, mitochondrial protein biosynthesis, substances metabolism, transport, and cell death. These results presented some useful information about the effect of glucotoxicity on the β‐cell mitochondria.