从多角度分析SARS-CoV-2和SARS冠状病毒(SARS-CoV)差异

新型冠状病毒肺炎(COVID-19)在全球范围内持续肆虐,感染人数与日俱增.COVID-19的病毒SARS-CoV-2与2003年发生的严重急性呼吸系统综合症冠状病毒(SARS coronavirus,SARS-CoV)同属冠状病毒.本研究就COVID-19与SARS冠状病毒的差异以及两种冠状病毒的中间宿主进行分析和探讨,并对SARS冠状病毒中间宿主果子狸的关系进行分析,以期为从野生动物角度防控病毒疾病提供参考,也为了解冠状病毒的的传播途径提供借鉴.     

冠状病毒S蛋白及其受体的结构和功能

冠状病毒是有包膜的单股正链RNA病毒。作为人和动物的重要致病原,冠状病毒感染主要导致宿主呼吸系统、肝脏、胃肠道以及神经系统出现急性或慢性症状。2000年以来,传染性非典型肺炎和中东呼吸综合征的暴发,以及猪流行性腹泻病毒在全球猪群中的暴发流行,引起大家对动物冠状病毒的极大重视。S蛋白具有受体结合活性和膜融合活性,是冠状病毒感染细胞的关键蛋白;S蛋白在病毒的组织或宿主嗜性和毒力等方面发挥重要作用。本文重点对近年来冠状病毒S蛋白的结构、功能以及S蛋白与受体相互作用的研究进行综述,以期为冠状病毒的入侵机制和反向遗传学研究以及受体阻断药物的开发提供参考。     

冠状病毒反向遗传操作技术及其应用进展

冠状病毒广泛存于自然界中,人和多种动物均易感。虽然冠状病毒具有相对严格的宿主特异性,但是其广泛的宿主性及其自身基因组的结构特性使得该病毒在进化过程中极易发生基因重组和突变,新型冠状病毒在此过程中不断出现。近年来,反向遗传学技术的发展为冠状病毒跨种属传播及致病机制、疫苗以及抗病毒药物的研发开辟了新的思路。对冠状病毒反向遗传操作技术的进展及其应用现状进行了简要综述与展望。     

应激颗粒在冠状病毒复制中的作用及机制

近年来多种冠状病毒感染后引发患者严重的呼吸道疾病,造成危害人类健康的严重公共卫生事件。新型冠状病毒（SARS-CoV-2）暴发以来,大量研究使得人们对冠状病毒与宿主相互作用机制有更多的了解,其中关于病毒感染后应激颗粒的形成和抗病毒作用也做了大量研究。病毒的RNA和蛋白可以激活宿主细胞内蛋白激酶R(Protein kinase R,PKR)及其下游信号,刺激应激颗粒（Stress granules,SGs）的形成,进而降低病毒在宿主细胞内所需蛋白的翻译水平,抑制病毒复制。然而冠状病毒与宿主长期博弈过程中也衍生出对抗细胞SGs的相应机制,比如利用蛋白与SGs相互作用,来抑制SGs的形成和解聚,逃逸细胞对病毒的抑制作用,保证病毒稳定复制,其中新型冠状病毒就是典型的例子。因此SGs的诱导为抗冠状病毒可能提供一个新型治疗策略。本文对冠状病毒感染抵抗细胞应激颗粒的形成促进其解聚的分子机制进行综述。     

棘突蛋白在冠状病毒跨宿主感染中的作用

冠状病毒感染有相对严格的宿主和组织特异性,其中部分病毒演化中会发生细胞嗜性改变。冠状病毒的跨宿主感染能力主要取决于病毒表面棘突蛋白的变异及其与受体相互作用的特异性改变。棘突蛋白的变异主要集中在受体结合域（RBD）,其他区域也与病毒感染的宿主细胞特异性有关。另外,较大的RNA基因组、独特的套氏亚基因组转录、复制过程中模板转换引起的高频率基因重组等使冠状病毒不断出现毒力或宿主变异,而共感染和持续性感染则为病毒重组及跨宿主感染提供了机会。     

猪流行性腹泻病毒(PEDV)与抗病毒天然免疫

猪流行性腹泻病毒(porcine epidemic diarrhea virus,PEDV)是引起猪流行性腹泻病等肠道疾病的一种动物冠状病毒.PEDV与宿主系统相互作用,特别是其对宿主抗病毒天然免疫调节作用和机制是目前动物冠状病毒研究的基础科学问题之一.基于作者近几年来对人类重要冠状病毒对宿主抗病毒天然免疫系统调节作用的研究,本文对PEDV基因组与编码蛋白主要功能以及PEDV调节宿主抗病毒天然免疫反应及其可能机制的进展和现状进行了分析.与人类冠状病毒相似,PEDV编码的木瓜样蛋白酶(papain like protease,PLP)是一个多功能蛋白酶,除了蛋白酶活性外,还具有去泛素化酶(DUB)活性和宿主干扰素拮抗活性,是PEDV编码的一种新型病毒来源DUB和宿主干扰素拮抗蛋白.这些研究为阐明PEDV对宿主抗病毒天然免疫反应调节作用和其致病机制提供了重要的理论依据,为研制新型PEDV免疫防治措施提供了重要理论基础.     

新型冠状病毒(SARS-CoV-2)蛋白靶位的生信分析

目前新型冠状病毒肺炎(COVID-19)疫情仍在全球肆虐,但尚无针对该病毒的治疗特效药.在此背景,以美国化学文摘社(Chemical Abstracts Service,CAS)提供的SARS-CoV-2病毒及宿主蛋白靶标为研究对象,运用基因功能富集、蛋白网络等方法进行生物信息分析.结果发现,人网格蛋白介导型内吞和依赖...     

黄病毒科和冠状病毒科病毒侵染中的外泌体研究进展

外泌体是一种在细胞间信息传递和物质运输中起重要作用的细胞外囊泡,它携带来源于宿主细胞的蛋白质、脂质和RNA等物质,并对受体细胞的生理状态产生重要影响.黄病毒科病毒如丙型肝炎病毒和冠状病毒科病毒如新型冠状病毒导致的疾病严重威胁人类健康,深入了解黄病毒科和冠状病毒科病毒与宿主的相互作用,对于筛选治疗的细胞靶点以及外泌体疫苗...     

冠状病毒分子生物学研究进展

1 冠状病毒概述 冠状病毒属于冠状病毒科,是病毒中的一个大家族,因电镜下病毒颗粒形似王冠而得名.形态为圆形、椭圆形或轻度多形性,直径为100nm～120nm.人冠状病毒有两个血清型,即HcoV-229E和HcoV-OC43,是人呼吸道感染的重要病原,人类20%的普通感冒由冠状病毒引起[1].儿童的冠状病毒感染并不常见,但是5～9岁儿童有50%可检出中和抗体,成人中70%中和抗体阳性.冠状病毒也是成人慢性气管炎患者急性加重的重要病因之一.由于冠状病毒易于变异,同一株病毒可重复感染人体.冠状病毒具有严格的宿主特异性,只感染自然宿主或亲缘关系密切的宿主.冠状病毒感染广泛分布于全世界各地,主要发生在冬春季节.     

SARS冠状病毒中的核衣壳蛋白

严重急性呼吸综合征(SARS)的元凶是一种新冠状病毒,研究病毒结构蛋白的功能有助于了解病毒的感染、复制和包装等生理过程。其中核衣壳蛋白是SARS冠状病毒中含量最丰富和最保守的结构蛋白,自身聚合后包被病毒RNA基因组形成螺旋状核壳体是SARS冠状病毒成熟的关键步骤;核衣壳蛋白能与病毒或宿主细胞中多种蛋白质相互作用,还能影响宿主细胞的多个通路。因此核衣壳蛋白是一个重要的多功能蛋白质,参与了病毒感染、复制和病毒包装等过程。     

Regulation of cell death during infection by the severe acute respiratory syndrome coronavirus and other coronaviruses

Both apoptosis and necrosis have been observed in cells infected by various coronaviruses, suggesting that the regulation of cell death is important for viral replication and/or pathogenesis. Expeditious research on the severe acute respiratory syndrome (SARS) coronavirus, one of the latest discovered coronaviruses that infect humans, has provided valuable insights into the molecular aspects of cell-death regulation during infection. Apoptosis was observed in vitro, while both apoptosis and necrosis were observed in tissues obtained from SARS patients. Viral proteins that can regulate apoptosis have been identified, and many of these also have the abilities to interfere with cellular functions. Occurrence of cell death in host cells during infection by other coronaviruses, such as the mouse hepatitis virus and transmissible porcine gastroenteritis virus, has also being extensively studied. The diverse cellular responses to infection revealed the complex manner by which coronaviruses affect cellular homeostasis and modulate cell death. As a result of the complex interplay between virus and host, infection of different cell types by the same virus does not necessarily activate the same cell-death pathway. Continuing research will lead to a better understanding of the regulation of cell death during viral infection and the identification of novel antiviral targets.     

冠状病毒的糖基化研究进展

冠状病毒(coronavirus)为一类具有囊膜结构、单股正链RNA病毒,可感染哺乳动物或禽类等.目前已知7种冠状病毒可造成人际间传播,其中以新型冠状病毒(Severe acute respiratory syndrome coronavirus-2,SARS-CoV-2)为代表,可引起严重的呼吸系统疾病,并感染全球数...     

Immunoinformatic analysis of the SARS-CoV-2 envelope protein as a strategy to assess cross-protection against COVID-19

Envelope protein of coronaviruses is a structural protein existing in both monomeric and homo-pentameric form. It has been related to a multitude of roles including virus infection, replication, dissemination and immune response stimulation. In the present study, we employed an immunoinformatic approach to investigate the major immunogenic domains of the SARS-CoV-2 envelope protein and map them among the homologue proteins of coronaviruses with tropism for animal species that are closely inter-related with the human beings population all over the world. Also, when not available, we predicted the envelope protein structural folding and mapped SARS-CoV-2 epitopes. Envelope sequences alignment provides evidence of high sequence homology for some of the investigated virus specimens; while the structural mapping of epitopes resulted in the interesting maintenance of the structural folding and epitope sequence localization also in the envelope proteins scoring a lower alignment score. In line with the One-Health approach, our evidences provide a molecular structural rationale for a potential role of taxonomically related coronaviruses in conferring protection from SARS-CoV-2 infection and identifying potential candidates for the development of diagnostic tools and prophylactic-oriented strategies.     

Envelope-binding domain in the cationic amino acid transporter determines the host range of ecotropic murine retroviruses.

Infection of rodent cells by ecotropic type C retroviruses requires the expression of a cationic amino acid transporter composed of multiple membrane-spanning domains. By exchanging portions of cDNAs encoding the permissive mouse and nonpermissive human transporters and examining their abilities to specify virus infection upon expression in human 293 cells, we have identified the amino acid residues in the extracellular loop connecting the fifth and sixth membrane-spanning segments of the mouse transporter that are required for both envelope gp70 binding and infection. These findings strongly suggest that the role of the mouse transporter in determining infection is to provide an envelope-binding site. This role is analogous to those of host membrane proteins composed of a single membrane-spanning domain that serve as binding proteins or receptors for other enveloped viruses such as human immunodeficiency virus, Epstein-Barr virus, and murine and human coronaviruses.     

Drugs targeting various stages of the SARS-CoV-2 life cycle: Exploring promising drugs for the treatment of Covid-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a positive-sense, single-stranded RNA virus that causes the potentially lethal Covid-19 respiratory tract infection. It does so by binding to host cell angiotensin converting enzyme 2 (ACE2) receptors, leading to endocytosis with the receptor, and subsequently using the host cell’s machinery to replicate copies of itself and invade new cells. The extent of the spread of infection in the body is dependent on the pattern of ACE2 expression and overreaction of the immune system. Additionally, by inducing an imbalance in the renin-angiotensin-aldosterone system (RAAS) and the loss of ACE2 would favour the progression of inflammatory and thrombotic processes in the lungs. No drug or vaccine has yet been approved to treat human coronaviruses. Hundreds of clinical trials on existing approved drugs from different classes acting on a multitude of targets in the virus life cycle are ongoing to examine potential effectiveness for the prevention and treatment of the infection. This review summarizes the SARS-CoV-2 virus life cycle in the host cell and provides a biological and pathological point of view for repurposed and experimental drugs for this novel coronavirus. The viral life cycle provides potential targets for drug therapy.     

Recombinant mouse hepatitis virus strain A59 from cloned, full-length cDNA replicates to high titers in vitro and is fully pathogenic in vivo

Mouse hepatitis virus (MHV) is the prototype of group II coronaviruses and one of the most extensively studied coronaviruses. Here, we describe a reverse genetic system for MHV (strain A59) based upon the cloning of a full-length genomic cDNA in vaccinia virus. We show that the recombinant virus generated from cloned cDNA replicates to the same titers as the parental virus in cell culture ( approximately 10(9) PFU/ml), has the same plaque morphology, and produces the same amounts and proportions of genomic and subgenomic mRNAs in virus-infected cells. In a mouse model of neurological infection, the recombinant and parental viruses are equally virulent, they replicate to the same titers in brain and liver, and they induce similar patterns of acute hepatitis, acute meningoencephalitis, and chronic demyelination. We also describe improvements in the use of the coronavirus reverse genetic system based on vaccinia virus cloning vectors. These modifications facilitate (i) the mutagenesis of cloned cDNA by using vaccinia virus-mediated homologous recombination and (ii) the rescue of recombinant coronaviruses by using a stable nucleocapsid protein-expressing cell line for the electroporation of infectious full-length genomes. Thus, our system represents a versatile and universal tool to study all aspects of MHV molecular biology and pathogenesis. We expect this system to provide valuable insights into the replication of group II coronaviruses that may lead to the development of novel strategies against coronavirus infections, including the related severe acute respiratory syndrome coronavirus.     

冠状病毒感染细胞的受体结合机制

病毒感染宿主细胞是病毒致病的关键所在,病毒感染细胞需要与其受体相结合,介导其与细胞的膜融合反应。本综述了冠状病毒受体结合机制的研究进展,以及其在SARS病毒致病机制中可能的作用。     

microRNAs与流感病毒感染

MicroRNAs是一类数目庞大,而且可以广泛参与到生命活动各个进程的非编码RNA分子,在病毒感染宿主过程中存在着复杂的microRNAs与病毒的相互作用。流感病毒感染可以引起宿主microRNAs表达谱的明显变化,流感病毒能通过调控某些microRNAs的表达来实现免疫逃逸等增强其感染能力;同时,宿主也可以通过某些microRNAs的变化启动相应的抗流感病毒反应。本文主要针对流感病毒感染过程中宿主-病毒二者在microRNA水平的相互作用进行综述,以期更好的了解流感病毒的致病机制,为抗流感病毒的新药研制提供新的思路。     

丙型肝炎病毒蛋白作用于细胞信号转导途径的研究进展

细胞信号转导异常往往与人类疾病的发生、发展密切相关。一些病毒致病和感染机制即为病毒抗原蛋白作用宿主细胞信号转导途径,导致宿主细胞内信号转导发生紊乱。丙型肝炎病毒（HCV）是引发慢性丙型肝炎,导致肝硬化和肝细胞癌发生的主要病原体,但目前HCV的致病机制与宿主内持续感染机制尚不清楚。HCV致病机制可能与HCV表达的蛋白质干扰宿主细胞信号转导途径而导致异常的细胞信号转导有关。研究HCV蛋白对宿主细胞信号转导途径的影响不仅有助于阐明其致病机制,还能为新药设计和寻找新的治疗方法提供新思路和新靶点。本文主要综述了近年来国内外有关HCV蛋白作用细胞信号转导途径的研究进展。