新型冠状病毒基因组结构与蛋白功能

2019年12月以来,武汉市暴发新型冠状病毒肺炎(coronavirus disease 2019,COVID-19)疫情并迅速蔓延全国,2020年1月30日被世界卫生组织(World Health Organization,WHO)列为“国际关注的突发公共卫生事件”(public health emergency of international concern,PHEIC)。核酸序列分析证明COVID-19由新型冠状病毒(2019 novel coronavirus,2019-nCoV)引起。2019-nCoV为正链单链RNA病毒,基因组长约30 kb,两端为非编码区,中间为非结构蛋白编码区和结构蛋白编码区。非结构蛋白编码区主要包括开放读码框架(open reading frame,ORF)1a和ORF1b基因,编码16个非结构蛋白(non-structural proteins,NSP),即NSP1～16。结构蛋白编码区主要编码刺突(spike,S)蛋白、包膜(envelope,E)蛋白、膜(membrane,M)蛋白和核衣壳(nucleocapsid,N)蛋白。深入了解2019-nCoV基因组的结构和蛋白功能,将为2019-nCoV相关的病毒溯源、复制增殖、致病免疫、药物与疫苗研发以及当前疫情的防控提供有力的支撑。     

NK细胞免疫治疗防治COVID-19应用潜力的研究进展

新型冠状病毒肺炎(corona virus disease 2019, COVID-19)作为一种新发型急性呼吸道传染病,目前已对全球公共卫生安全构成严重威胁。严重急性呼吸综合征冠状病毒2(severe acute respiratory syndrome coronavirus 2, SARS-CoV-2)感染导致COVID-19重症患者淋巴细胞减少、淋巴细胞功能障碍并引起不可控的炎症反应。由于自然杀伤细胞(natural killer cell, NK细胞)在抗病毒和免疫调节中具有重要作用,以NK细胞为基础的免疫治疗可能是有效抗击COVID-19的治疗策略之一。现就已发表的SARS-CoV-2临床研究报告,整理介绍了该病毒的基本特征及COVID-19患者的主要免疫病理学状态,阐述NK细胞在抗病毒领域的潜在作用机制与研究进展,并对NK细胞防治COVID-19的免疫治疗策略及所面临的问题与挑战作一综述。     

新型冠状病毒的结构基础与新型冠状病毒肺炎的临床药物治疗

新型冠状病毒肺炎(corona virus disease 2019, COVID-19)是指由新型冠状病毒(severe acute respiratory syndrome coronavirus2, SARS-CoV-2)感染导致的肺炎。SARS-CoV-2结合细胞表面受体——血管紧张素转化酶2 (angiotensin-converting enzyme 2,ACE2)感染肺部细胞,导致白细胞浸润,血管和肺泡壁通透性增加,肺表面活性物质减少,引起呼吸系统症状。局部的炎症加重引起细胞因子风暴,造成全身性炎症反应综合征。2019年12月,武汉市卫生健康委员会报告了多例新型肺炎,分离并确定了病原体SARS-CoV-2。截至2020年9月13日,全世界216个国家或地区受累,2 860余万人确诊COVID-19,90余万人死于该疾病,病死率高达3.20%。到目前为止,尚无特效药物可治疗COVID-19,因此解析病毒结构,探索治疗药物显得尤其重要。本文总结了SARS-CoV-2的病毒结构和COVID-19的临床药物治疗,并分析了他们之间可能的相关性。     

SARS-CoV感染Vero E6细胞诱导细胞凋亡

为了确定SARS冠状病毒(SARS-CoV)感染Vero E6是否引起细胞凋亡,我们利用细胞DNA琼脂糖电泳,感染细胞的间接荧光染色和Hoechst 33258细胞核染色,以及流式细胞仪分析等方法证明了SARS-CoV感染的Vero E6具有典型的凋亡细胞学和生物化学特征.实验证明具有细胞凋亡特征的所有细胞均为处于感染晚期的细胞.表现明显细胞病变(CPE)的细胞大多已经出现核质凝缩或形成凋亡小体进入细胞凋亡的过程.可以断定SARS-CoV感染Vero E6细胞诱发了细胞凋亡.     

冠状病毒相关研究工具进展

冠状病毒宿主范围广,可跨越动物宿主屏障感染人类,甚至造成人际传播。2019年12月新型冠状病毒(2019novel coronavirus,2019-nCoV)在中国武汉引发肺炎疫情,引起全世界的关注。截至2020年2月10日,中国实验室确诊病例40 235例,死亡909例,病死率2.3%;重症6 484例,重症率16.1%;全球已有25个国家和地区有确诊病例。至此,2019-nCoV成为继出现在中国内地的严重急性呼吸综合征冠状病毒(Severe acute respiratory syndrome coronavirus,SARS-CoV)、出现在中东沙特的中东呼吸综合征冠状病毒(Middle East respiratory syndrome coronavirus,MERS-CoV)之后,第三种可引起人类致死的冠状病毒。对于2019-nCoV的来源、中间宿主、传播方式、致病机制、防控措施等一系列问题,丞待科学家去研究探索。了解新病原的研究工具,借鉴SARS-CoV和MERS-CoV的研究经验,在基因合成技术提升的背景下,仅需新病原基因组序列就可开发基础研究工具,进行减毒疫苗株、筛选药物和致病机制等的研究探讨。因此,本文就目前冠状病毒基础研究工具做一综述。     

2019冠状病毒病(COVID-19)实验室诊断方法的应用现状

严重急性呼吸综合征冠状病毒2 (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2)系通过分析鉴定2019年武汉不明原因的肺炎病例而被发现。世界卫生组织将该新型冠状病毒感染的肺炎命名为2019冠状病毒病(corona virus disease 2019, COVID-19)。COVID-19的实验室诊断方法主要有基于病毒核酸的病原学检查、通过特异性抗体检测的血清学检测以及一般检查。目前,实时逆转录PCR是COVID-19确诊的金标准,但该方法存在漏检和假阴性的问题,因此,为了更有效防控COVID-19,有必要发展高质量、高敏感的诊断方法。本文综述了COVID-19实验室诊断方法的应用现状及最新进展,以期为快速准确诊断COVID-19提供参考。     

新型冠状病毒的动物源性和传染源控制

根据现有的数据,新型冠状病毒(2019 novel coronavirus,2019-nCoV)比严重急性呼吸综合征冠状病毒(severe acute respiratory syndrome coronavirus,SARS-CoV)的传染性强、传播速度快、疫情规模大、病死率低。其传染性、传播速度和疫情规模似乎具有甲型流感病毒(influenza A virus)的特点。尽管2019-nCoV来源于何种动物尚无定论,但它与SARS-CoV同属冠状病毒,具有共同之处。如果流行过后 2019-nCoV没能在人群中持续传播和存在(如同SARS-CoV一样),则控制野生动物传染源乃重中之重;如果2019-nCoV获得了能在人群中持续传播的能力,预防控制策略将与SARS-CoV明显不同,疫苗便成为至关重要的手段。     

SARS—CoV感染Vero E6细胞诱导细胞凋亡

为了确定SARS冠状病毒(SARS—CoV)感染Vero E6是否引起细胞凋亡,我们利用细胞DNA琼脂糖电泳,感染细胞的间接荧光染色和Hoechst 33258细胞核染色,以及流式细胞仪分析等方法证明了SARS-CoV感染的Veto E6具有典型的凋亡细胞学和生物化学特征。实验证明具有细胞凋亡特征的所有细胞均为处于感染晚期的细胞。表现明显细胞病变(CPE)的细胞大多已经出现核质凝缩或形成凋亡小体进入细胞凋亡的过程。可以断定SARS-CoV感染Vero E6细胞诱发了细胞凋亡。     

脐带间充质干细胞治疗新型冠状病毒肺炎2例

新型冠状病毒感染疫情,已经发展为全球公共卫生紧急事件。世界卫生组织将此病毒命名为2019新型冠状病毒(2019-nCoV),将引发的疾病命名为2019冠状病毒病(Coronavirus Disease-19,COVID-19)。COVID-19患者以发热、乏力、干咳为主要临床表现,少数患者伴有鼻塞、流涕和腹泻等症状。重症患者多在发病1周后出现呼吸困难和(或)低氧血症,严重者快速进展为急性呼吸窘迫综合征、脓毒症休克、难以纠正的代谢性酸中毒和出凝血功能障碍等。COVID-19目前尚无特效治疗手段,有学者认为,避免细胞因子风暴可能是治疗COVID-19感染患者的关键。间充质干细胞(mesenchymal stem cells,MSCs)具有强大的免疫调节能力,可能对预防或减弱细胞因子风暴、降低本病的发病率和死亡率具有一定的作用。海南医学院第二附属医院于2020年2月采用脐带间充质干细胞治疗2例新型冠状病毒肺炎患者,取得一定疗效。     

严重急性呼吸综合征冠状病毒诊断标志物动态变化及检测方法的研究进展

2019-冠状病毒病(coronavirus disease 2019, COVID-19)在全球范围内流行,患者出现严重急性呼吸系统疾病,传染性高于2003年暴发的严重急性呼吸综合征(severe acute respiratory syndrome, SARS)。COVID-19严重影响了人类的健康,同时引起了人们的恐慌。因此,快速、精准地诊断COVID-19患者,阻断病毒快速传播至关重要,但是在COVID-19诊断中存在早期漏检和后期复阳等情况。现综述严重急性呼吸综合征冠状病毒(severe acute respiratory syndrome coronavirus, SARS-CoV)感染后各标志物的动态变化及检测意义,并将其与严重急性呼吸综合征冠状病毒2(severe acute respiratory syndrome coronavirus 2, SARS-CoV-2)进行比较,以期为SARS-CoV-2等冠状病毒的高效诊断提供借鉴。     

2019新型冠状病毒信息库

2019年12月在中国武汉开始爆发的新型肺炎已造成全球25个国家/地区的31516人感染、638人死亡(截止2020年2月7日16时),引起该肺炎的病毒被世界卫生组织命名为2019新型冠状病毒(2019-nCoV)。为促进2019-nCoV数据共享应用并及时向全球公众提供病毒的相关信息,国家生物信息中心(CNCB)/国家基因组科学数据中心(NGDC)建立了2019新型冠状病毒信息库(2019nCoVR,https://bigd.big.ac.cn/ncov)。该信息库整合了来自德国全球流感病毒数据库、美国国家生物技术信息中心、深圳(国家)基因库、国家微生物科学数据中心及CNCB/NGDC等机构公开发布的2019-nCoV核苷酸和蛋白质序列数据、元信息、学术文献、新闻动态、科普文章等信息,开展了不同冠状病毒株的基因组序列变异分析并提供可视化展示。同时,2019nCoVR无缝对接CNCB/NGDC的相关数据库,提供新测序病毒株系的基因组原始测序数据、组装后序列的在线汇交、管理与共享、国际数据库同步发布等数据服务。本文对2019nCoVR数据汇交、管理、发布及使用等进行全面阐述,以方便用户了解该信息库各项功能及数据状况,为加速开展病毒的分类溯源、变异演化、快速检测、药物研发以及新型肺炎的精准预防与治疗等研究提供重要基础。     

Mesenchymal stem cells: a new front emerges in coronavirus disease 2019 treatment

Currently, treating coronavirus disease 2019 (COVID-19) patients, particularly those afflicted with severe pneumonia, is challenging, as no effective pharmacotherapy for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exists. Severe pneumonia is recognized as a clinical syndrome characterized by hyper-induction of pro-inflammatory cytokine production, which can induce organ damage, followed by edema, dysfunction of air exchange, acute respiratory distress syndrome, acute cardiac injury, secondary infection and increased mortality. Owing to the immunoregulatory and differentiation potential of mesenchymal stem cells (MSCs), we aimed to outline current insights into the clinical application of MSCs in COVID-19 patients. Based on results from preliminary clinical investigations, it can be predicted that MSC therapy for patients infected with SARS-CoV-2 is safe and effective, although multiple clinical trials with a protracted follow-up will be necessary to determine the long-term effects of the treatment on COVID-19 patients.     

Development of T-cell immunity in a liver and hematopoietic stem cell transplant recipient following coronavirus disease 2019 infection

The outbreak of coronavirus disease 2019 (COVID-19) has disproportionately affected patients with comorbidities, including recipients of solid organ and hematopoietic stem cell transplants (SCT). Upon recovery from COVID-19, the degree of the immunological protection from reinfection remains unclear. Here we describe a 33-year-old patient with erythropoietic protoporphyria (EPP) who had undergone liver transplantation with splenectomy followed by allogeneic SCT in 2013 after an initial failed liver and umbilical cord transplant. The patient developed mild upper respiratory symptoms in the spring of 2020 and was found to have anti-SARS-CoV2 antibodies suggesting past infection. A comprehensive analysis of T cell functionality in peripheral blood from this patient revealed robust in vitro responses against SARS CoV2 antigens Spike (S) 1 and 2, membrane (M) and nucleoprotein (NP), comparable to the reactivity against common antigens from CMV, EBV, Ad and BK viruses, while only low reactivity was seen in healthy donors without documented history of COVID-19. Moreover, the patient displayed a marked recognition of counterpart antigens from related human coronaviruses (hCoVs) 229E, OC43, NL63 and HKU1. Thus, despite lifelong immunosuppression, this survivor of COVID-19 retained a remarkable degree of immunocompetence and showed broad-spectrum T cell memory specific for SARS-CoV2 and related hCoVs including less studied hCoV M and NP antigens. The study highlights the role of cellular immunity after natural COVID-19 infection, suggesting broader use of T cell assays as a tool for risk stratification, measurement of immunocompetence and/or post-infection or post-vaccination protection, and possible T cell-based adoptive immunotherapy strategies in high-risk patients.     

Mesenchymal stromal cell therapy for coronavirus disease 2019: which? when? and how much?

Mesenchymal stromal cells (MSCs) are under active consideration as a treatment strategy for controlling the hyper-inflammation and slow disease progression associated with coronavirus disease 2019 (COVID-19). The possible mechanism of protection through their immunoregulatory and paracrine action has been reviewed extensively. However, the importance of process control in achieving consistent cell quality, maximum safety and efficacy—for which the three key questions are which, when and how much—remains unaddressed. Any commonality, if it exists, in ongoing clinical trials has yet to be analyzed and reviewed. In this review, the authors have therefore compiled study design data from ongoing clinical trials to address the key questions of “which” with regard to tissue source, donor profile, isolation technique, culture conditions, long-term culture and cryopreservation of MSCs; “when” with regard to defining the transplantation window by identifying and staging patients based on their pro-inflammatory profile; and “how much” with regard to the number of cells in a single administration, number of doses and route of transplantation. To homogenize MSC therapy for COVID-19 on a global scale and to make it readily available in large numbers, a shared understanding and uniform agreement with respect to these fundamental issues are essential.     

2019新型冠状病毒基因组的生物信息学分析

2019年12月,中国武汉报道了冠状病毒引起的肺炎,其临床症状与2003年爆发的严重急性呼吸综合征(Severe Acute Respiratory Syndrome, SARS)不同,因此推断该病毒可能是冠状病毒的一个新变种。不同于简单使用全基因组序列的其它研究,我们于2018年在国际上首次提出分子功能与进化分析相结合的研究思想,并应用于Beta冠状病毒B亚群(BB冠状病毒)基因组的研究。在这一思想指导下,本研究使用BB冠状病毒基因组中的一个互补回文序列(命名为Nankai complemented palindrome)与其所在的编码区(命名为Nankai CDS)对新发布的2019新型冠状病毒基因组(GenBank:MN908947)进行分析以期准确溯源,并对BB冠状病毒的跨物种传播和宿主适应性进行初步研究。溯源分析的结果支持2019新型冠状病毒源自蝙蝠,但与SARS冠状病毒差异巨大,这一结果与两者临床症状差异一致。本研究的最重要发现是BB冠状病毒存在大量的可变翻译,从分子水平揭示了BB冠状病毒变异快、多样性高的特点。从BB冠状病毒可变翻译中获取的信息可应用于(但不限于)其快速检测、基因分型、疫苗开发以及药物设计。另外,我们推断BB冠状病毒可能通过可变翻译以适应不同宿主。基于大量基因组数据的实证分析,本研究在国际上首次从分子水平尝试解释了BB冠状病毒变异快、宿主多且具有较强的宿主适应性的原因。     

A global treatments for coronaviruses including COVID-19

In late December 2019 in Wuhan, China, several patients with viral pneumonia were identified as 2019 novel coronavirus (2019-nCoV). So far, there are no specific treatments for patients with coronavirus disease-19 (COVID-19), and the treatments available today are based on previous experience with similar viruses such as severe acute respiratory syndrome-related coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and Influenza virus. In this article, we have tried to reach a therapeutic window of drugs available to patients with COVID-19. Cathepsin L is required for entry of the 2019-nCoV virus into the cell as target teicoplanin inhibits virus replication. Angiotensin-converting-enzyme 2 (ACE2) in soluble form as a recombinant protein can prevent the spread of coronavirus by restricting binding and entry. In patients with COVID-19, hydroxychloroquine decreases the inflammatory response and cytokine storm, but overdose causes toxicity and mortality. Neuraminidase inhibitors such as oseltamivir, peramivir, and zanamivir are invalid for 2019-nCoV and are not recommended for treatment but protease inhibitors such as lopinavir/ritonavir (LPV/r) inhibit the progression of MERS-CoV disease and can be useful for patients of COVID-19 and, in combination with Arbidol, has a direct antiviral effect on early replication of SARS-CoV. Ribavirin reduces hemoglobin concentrations in respiratory patients, and remdesivir improves respiratory symptoms. Use of ribavirin in combination with LPV/r in patients with SARS-CoV reduces acute respiratory distress syndrome and mortality, which has a significant protective effect with the addition of corticosteroids. Favipiravir increases clinical recovery and reduces respiratory problems and has a stronger antiviral effect than LPV/r. currently, appropriate treatment for patients with COVID-19 is an ACE2 inhibitor and a clinical problem reducing agent such as favipiravir in addition to hydroxychloroquine and corticosteroids.     

Stem cell therapy in coronavirus disease 2019: current evidence and future potential

The end of 2019 saw the beginning of the coronavirus disease 2019 (COVID-19) pandemic that soared in 2020, affecting 215 countries worldwide, with no signs of abating. In an effort to contain the spread of the disease and treat the infected, researchers are racing against several odds to find an effective solution. The unavailability of timely and affordable or definitive treatment has caused significant morbidity and mortality. Acute respiratory distress syndrome (ARDS) caused by an unregulated host inflammatory response toward the viral infection, followed by multi-organ dysfunction or failure, is one of the primary causes of death in severe cases of COVID-19 infection. Currently, empirical management of respiratory and hematological manifestations along with anti-viral agents is being used to treat the infection. The quest is on for both a vaccine and a more definitive management protocol to curtail the spread. Researchers and clinicians are also exploring the possibility of using cell therapy for severe cases of COVID-19 with ARDS. Mesenchymal stromal cells are known to have immunomodulatory properties and have previously been used to treat viral infections. This review explores the potential of mesenchymal stromal cells as cell therapy for ARDS.     

关于新型冠状病毒肺炎的深度思考：共感染

新型冠状病毒肺炎(coronavirus disease 2019，COVID-19)患者的共感染备受临床关注。本文着重分析了现有研究中的不足，包括与共感染相关术语的定义及运用；病原学检测新技术的临床价值和适用范围的界定；诊断标准的确立及研究内容和方法等，并提出改进意见。