SARS-CoV的S蛋白诱导呼吸道上皮细胞合成释放IP-10的信号分子机制研究

目的：研究SARS冠状病毒S蛋白诱导呼吸道上皮细胞合成释放IP-10（interferon-gamma inducible protein 10）的信号分子机制。方法：通过基因芯片检测SARS冠状病毒的S蛋白作用于人支气管上皮细胞16HBE后信号通路基因表达谱的变化；采纳RT-PCR、EMSA、Western blotting等方法进一步分析JAK-STAT通路中信号分子的磷酸化、IRF-1和IP-10基因表达的变化及其相应信号分子抑制剂对表达水平的影响。结果：S蛋白作用于人支气管上皮细胞16HBE诱导了JAK-STAT信号通路涉及的重要转录因子基因IRF-1的表达，该信号通路的转录因子STAT1在刺激后15 min发生磷酸化，2 h即可检出IP-10基因的表达， IP-10的表达可以完全被STAT1、JAK2抑制剂阻断。EMSA显示：支气管上皮细胞在S蛋白的作用下，其核蛋白能够特异性与ISRE和GAS DNA基序相结合，而不能与NF-κB的 DNA基序相结合。结论： SARS－CoV的S蛋白通过激活JAK-STAT信号转导通路诱导IP-10在宿主细胞的生成。提示病毒诱导的JAK-STAT信号通路激活在病毒感染相关的急性肺损伤发生中具有重要地位。     

干扰素诱导基因的表达调控及作用机制

在病毒感染过程中,天然免疫系统通过模式识别受体识别入侵病毒的结构成分,启动一系列细胞内信号转导,诱导Ⅰ型干扰素的产生。Ⅰ型干扰素随后激活下游干扰素信号通路,转录多种干扰素诱导基因(ISG),启动宿主对病毒等的防御反应。ISG具有抗病毒及免疫调节等多种生物学功能,然而目前仅有少部分ISG在免疫反应中的作用机理得到较为系统的研究。本文综述了Ⅰ型干扰素和ISG的产生、ISG抵制病毒感染的最新分子机制以及ISG的免疫调控功能,并讨论了ISG在自身免疫性疾病的作用。     

SARS冠状病毒全基因组cDNA芯片的研制以及人重组干扰素α2b抑制SARS病毒复制分子机制的初步研究

目的 在细胞水平上，利用研制的SARS病毒全基因组芯片技术探讨人重组干扰素α2b抑制SARS病毒复制的分子机制。方法 根据已经发表的SARS病毒基因组全序列和生物信息学软件分析，设计包括SABS病毒全基因组的各个可能编码区的PCR引物；将所有PCR产物用来制备SABS病毒的全基因组cDNA芯片。利用该芯片来探讨人重组干扰素α2b抑制SARS病毒复制的分子基础。结果 通过：PCR方法研制了SARS病毒全基因组的cDNA芯片，并说明cDNA芯片可以准确地检测SARS病毒各个基因的RNA水平。利用这一技术研究了于扰素抗SARS病毒的分子机制。结果表明，人重组干扰素α2b可以明显抑制SARS病毒复制过程中几乎所有病毒RNAs的转录，并呈现一定的剂量关系；并发现一个目前还没有确定功能的SARS病毒新基因，命名为U基因，转录最早，转录水平最高，对干扰素的抑制作用也很敏感；它可能在病毒的转录复制过程中发挥重要作用。结论 SARS冠状病毒cDNA芯片可以用来研究病毒复制的分子机制以及相关抗病毒药物包括干扰素的研究。本文在分子水平上研究了人于扰素α2b抑制SARS病毒复制的基因转录动态，并就干扰素α2b抑制SARS病毒的可能分子机制及其潜在的应用价值进行了讨论。     

核苷酸结合寡聚结构域样受体家族成员X1(NLRX1)在抗病毒固有免疫应答中的研究进展

NOD样受体家族成员X1(NLRX1)与机体抗病毒固有免疫反应密切相关。NLRX1对病毒感染宿主的免疫应答具有抑制作用,能通过多种机制削弱机体应对病毒感染的免疫应答反应,导致病毒复制增强并影响抗病毒治疗的效果。我们首先对NLRX1的结构、定位及功能进行详细概括,阐明定位于线粒体的NLRX1发挥着负性调节因子的作用,通过多种信号通路的作用减弱固有免疫对病毒感染的应答。随后以人类免疫缺陷病毒1(HIV-1)感染为例,详细总结NLRX1在抗病毒免疫反应中的负性调节作用及其分子机制,为深入研究宿主固有免疫受体在抗病毒感染免疫中的作用提供参考。     

T细胞衰老与慢性肝炎病毒感染相关研究进展

机体年龄的增长和病毒感染都会引起免疫衰老,主要表现在T淋巴细胞数量、细胞亚群数量、细胞膜表面分子及功能发生变化,导致T细胞免疫功能下降和异常。T淋巴细胞衰老的主要原因是端粒长度缩短或者端粒酶功能受损而导致。而影响端粒长度和端粒酶功能的是活性氧的产生以及细胞应激通路引起的DNA损伤。当乙型肝炎病毒、丙型肝炎病毒感染机体后,机体的CD4+T淋巴细胞和CD8+T淋巴细胞功能会受到影响,表达衰老相关蛋白。我们总结了引起T细胞衰老的原因,T细胞衰老后特征和相关的信号通路,以及T细胞衰老在慢性肝炎感染免疫失调中的作用机制。     

microRNA在固有免疫调控中作用的研究进展

microRNA(miRNA)是一类内源性的短链非编码RNA分子,能与特定的信使RNA靶向结合,在转录后水平调控基因表达.miRNA可在多个环节参与调控机体固有免疫反应.微生物感染时,miRNA可通过调控模式识别受体信号通路及产生的细胞因子,负性或正性调控固有免疫应答.在病毒感染时,宿主编码的miRNA能抑制病毒复制,...     

川穹嗪对糖尿病肾病大鼠肾脏的保护作用及可能机制

目的 观察川穹嗪对糖尿病肾病大鼠肾脏的保护作用及其可能的信号机制.方法 将36只SD大鼠随机分为对照组(control)、糖尿病肾病模型组(DN)和川穹嗪治疗组(TMP),每组12只.于造模成功后第8周,生化分析仪检测各组大鼠血清肌酐(Scr)、尿素氮(BUN)、总蛋白(TP)、白蛋白丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)的含量;测定肾脏指数;HE染色观察各组大鼠肾组织病理学改变;ELISA方法检测各组大鼠肾组织IL-6、C反应蛋白(CRP)与肿瘤坏死因子α(TNF-α)表达水平;Western blot方法检测各组大鼠肾组织中JAK激酶2(JAK2)、p-JAK2、信号转导与转录因子3(STAT3)及p-STAT3的蛋白表达.结果 川穹嗪能够降低糖尿病肾病大鼠血清中Scr、BUN含量(P＜0.05);降低糖尿病肾病大鼠肾脏指数,减轻肾脏的病理损伤(P＜0.05);降低糖尿病肾病大鼠肾组织IL-6、CRP与TNF-α水平(P＜0.05);下调糖尿病肾病大鼠肾组织p-JAK2及p-STAT3的蛋白表达(P＜0.05).结论 川穹嗪可能通过抑制JAK2/STAT3信号通路减轻糖尿病肾病大鼠的炎症反应.     

Toll样受体介导的抗病毒感染效应及其机制

Toll样受体(Toll Like Receptors,TLRs)在天然免疫中发挥着重要的作用。近年,越来越多的证据表明TLRs也参与了天然免疫系统对病毒的识别,同时它在病毒感染及其转归中也扮演了重要的角色。TLR3、TLR4、TLR7、TLR8、TLR9等TLRs可识别特异性蛋白、DNA和RNA等病毒源性分子,启动胞内抗病毒信号传导机制,通过一系列转接蛋白和转录因子,介导了以干扰素反应为主要机制的固有免疫防御机制,同时也参与调控针对病毒的特异性免疫应答。此外,某些病毒具有针对TLRs的免疫逃逸机制。     

外泌体在新型冠状病毒感染和传播中作用的研究进展

外泌体在COVID-19的病理过程中起着重要作用，与其携带的核酸、蛋白质等物质，共同调控SARS-CoV-2的感染和传播。病毒感染细胞通过内体途径产生含SARS-CoV-2病毒颗粒的外泌体，介导病毒向健康细胞感染和传播，造成组织损伤和多器官功能障碍。同时，外泌体作为细胞间通讯的关键介质，起到免疫激活作用，促进机体产生免疫反应，抵抗病毒入侵。此外，外泌体协助病毒逃避机体免疫，是SARS-CoV-2再感染的潜在手段。总之，外泌体在新型冠状病毒感染和传播中的作用为其在诊断、防治COVID-19等方面的应用提供新思路。     

基于转录组测序技术分析中医三阳合治法减轻流感病毒致小鼠结肠损伤的作用机制

目的应用转录组测序技术研究麻杏石甘汤合小柴胡汤(以下称"三阳合治")减轻流感病毒感染小鼠结肠损伤的作用机制。方法甲型流感病毒H1N1滴鼻诱导流感病毒致小鼠结肠损伤模型。小鼠分为空白组、模型组和三阳合治组, 每组10只小鼠。模型组、三阳合治组分别以PBS、麻杏石甘汤合小柴胡汤灌胃, 7天后取各组小鼠结肠组织, 观察结肠长度及结肠病理损伤情况, 并进行转录组测序, 筛选三阳合治组与模型组显著差异基因进行GO、KEGG和GSEA分析。结果三阳合治干预后显著改善了小鼠的结肠长度, 减轻了结肠病理损伤。三阳合治组与模型组有92个显著差异表达基因, GO分析提示差异基因富集于细胞因子和趋化因子产生的调节、炎症应答、防御反应、免疫反应、NIK/NF-κB信号的调节以及MAPK级联等生物过程, 以及刷状缘膜、刷状缘、微绒毛等与肠道屏障相关的细胞组分。KEGG分析提示差异基因富集于Toll样受体信号通路、产生IgA的肠道免疫网络、补体和凝血级联以及PPAR信号通路等。GSEA分析提示产生IgA的肠道免疫网络、PPAR信号通路以及丙酸代谢和丁酸盐代谢等在三阳合治干预后显著上调, 而凋亡和MAPK信号通路在...     

Severe acute respiratory syndrome coronavirus 2 causes lung inflammation and injury

BackgroundAs of 14 October 2021, coronavirus disease 2019 (COVID-19) has affected more than 246 million individuals and caused more than 4.9 million deaths worldwide. COVID-19 has caused significant damage to the health, economy and lives of people worldwide. Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is not as lethal as SARS coronavirus or Middle East respiratory syndrome coronavirus, its high transmissibility has had disastrous consequences for public health and health-care systems worldwide given the lack of effective treatment at present.ObjectivesTo clarify the mechanisms by which SARS-CoV-2 caused lung inflammation and injury, from the molecular mechanism to lung damage and tissue repair, from research to clinical practice, and then presented clinical requirements.SourcesReferences for this review were identified through searches ‘(COVID-19 [Title]) OR (SARS-CoV-2 [Title])’ on PubMed, and focused on the pathological damage and clinical practice of COVID-19.ContentWe comprehensively reviewed the process of lung inflammation and injury during SARS-CoV-2 infection, including pyroptosis of alveolar epithelial cells, cytokine storm and thrombotic inflammatory mechanisms.ImplicationsThis review describes SARS-CoV-2 in comparison to SARS and explores why most people have mild inflammatory responses, even asymptomatic infections, and only a few develop severe disease. It suggests that future therapeutic strategies may be targeted antiviral therapy, the pathogenic pathways in the lung inflammatory response, and enhancing repair and regeneration in lung injury.     

The role of HMGB1 in COVID-19-induced cytokine storm and its potential therapeutic targets: A review

Hyperinflammation characterized by elevated proinflammatory cytokines known as ‘cytokine storms’ is the major cause of high severity and mortality seen in COVID-19 patients. The pathology behind the cytokine storms is currently unknown. Increased HMGB1 levels in serum/plasma of COVID-19 patients were reported by many studies, which positively correlated with the level of proinflammatory cytokines. Dead cells following SARS-CoV-2 infection might release a large amount of HMGB1 and RNA of SARS-CoV-2 into extracellular space. HMGB1 is a well-known inflammatory mediator. Additionally, extracellular HMGB1 might interact with SARS-CoV-2 RNA because of its high capability to bind with a wide variety of molecules including nucleic acids and could trigger massive proinflammatory immune responses. This review aimed to critically explore the many possible pathways by which HMGB1-SARS-CoV-2 RNA complexes mediate proinflammatory responses in COVID-19. The contribution of these pathways to impair host immune responses against SARS-CoV-2 infection leading to a cytokine storm was also evaluated. Moreover, since blocking the HMGB1-SARS-CoV-2 RNA interaction might have therapeutic value, some of the HMGB1 antagonists have been reviewed. The HMGB1- SARS-CoV-2 RNA complexes might trigger endocytosis via RAGE which is linked to lysosomal rupture, PRRs activation, and pyroptotic death. High levels of the proinflammatory cytokines produced might suppress many immune cells leading to uncontrolled viral infection and cell damage with more HMGB1 released. Altogether these mechanisms might initiate a proinflammatory cycle leading to a cytokine storm. HMGB1 antagonists could be considered to give benefit in alleviating cytokine storms and serve as a potential candidate for COVID-19 therapy.     

Expanding the frontiers of existing antiviral drugs: possible effects of HIV-1 protease inhibitors against SARS and avian influenza.

When unexpected diseases such as the severe acute respiratory syndrome (SARS) and avian influenza become a serious threat to public health, an immediate response is imperative. This should take into consideration existing licensed antiviral drugs against other viral diseases already known to be safe for use in humans. In this report, evidence is presented that HIV-1 protease inhibitors (PIs) currently used in anti-HIV-1 therapies might exert some effects on SARS and perhaps, on avian influenza. Evidence for the potential benefits of PIs against the SARS coronavirus (SARS-CoV) is provided by empirical clinical studies, in vivo viral inhibition assays and computational simulations of the docking of these compounds to the active site of the main SARS-CoV protease. As suggested by in silico docking of these molecules to a theoretical model of a subunit of type A influenza virus RNA-dependent RNA polymerase, there also exists a remote possibility that these PIs may have an effect on avian influenza viruses. Although this evidence is still far from being definitive, the results so far obtained suggest that PIs should be seriously taken into consideration for further testing as potential therapeutic agents for SARS and avian influenza.     

Pathology and pathogenesis of severe acute respiratory syndrome

Severe acute respiratory syndrome (SARS) is an emerging infectious viral disease characterized by severe clinical manifestations of the lower respiratory tract. The pathogenesis of SARS is highly complex, with multiple factors leading to severe injury in the lungs and dissemination of the virus to several other organs. The SARS coronavirus targets the epithelial cells of the respiratory tract, resulting in diffuse alveolar damage. Several organs/cell types may be infected in the course of the illness, including mucosal cells of the intestines, tubular epithelial cells of the kidneys, neurons of the brain, and several types of immune cells, and certain organs may suffer from indirect injury. Extensive studies have provided a basic understanding of the pathogenesis of this disease. In this review we describe the most significant pathological features of SARS, explore the etiological factors causing these pathological changes, and discuss the major pathogenetic mechanisms. The latter include dysregulation of cytokines/chemokines, deficiencies in the innate immune response, direct infection of immune cells, direct viral cytopathic effects, down-regulation of lung protective angiotensin converting enzyme 2, autoimmunity, and genetic factors. It seems that both abnormal immune responses and injury to immune cells may be key factors in the pathogenesis of this new disease.     

PI3K/Akt/mTOR pathway: a potential target for anti-SARS-CoV-2 therapy

Coronavirus disease 2019 (COVID-19) is a viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A single-stranded RNA virus from a β-Coronaviridae family causes acute clinical manifestations. Its high death rate and severe clinical symptoms have turned it into the most significant challenge worldwide. Up until now, several effective COVID-19 vaccines have been designed and marketed, but our data on specialized therapeutic drugs for the treatment of COVID-19 is still limited. In order to synthesis virus particles, SARS-CoV-2 uses host metabolic pathways such as phosphoinositide3-kinase (PI3K)/protein kinase B (PKB, also known as AKT)/mammalian target of rapamycin (mTOR). mTOR is involved in multiple biological processes. Over-activation of the mTOR pathway improves viral replication, which makes it a possible target in COVID-19 therapy. Clinical data shows the hyperactivation of the mTOR pathway in lung tissues during respiratory viral infections. However, the exact impact of mTOR pathway inhibitors on the COVID-19 severity and death rate is yet to be thoroughly investigated. There are several mTOR pathway inhibitors. Rapamycin is the most famous inhibitor of mTORC1 among all. Studies on other respiratory viruses suggest that the therapeutic inhibitors of the mTOR pathway, especially rapamycin, can be a potential approach to anti-SARS-CoV-2 therapy. Using therapeutic methods that inhibit harmful immune responses can open a new chapter in treating severe COVID-19 disease. We highlighted the potential contribution of PI3K/Akt/mTOR inhibitors in the treatment of COVID-19.

     

Puzzling out the COVID-19: Therapy targeting HLA-G and HLA-E

SARS-CoV2 might conduce to rapid respiratory complications challenging healthcare systems worldwide. Immunological mechanisms associated to SARS-CoV2 infection are complex and not yet clearly elucidated. Arguments are in favour of a well host-adapted virus. Here I draw a systemic immunological representation linking actual SARS-CoV2 infection literature that hopefully might guide healthcare decisions to treat COVID-19. I suggest HLA-G and HLA-E, non classical HLA class I molecules, in the core of COVID-19 complications. These molecules are powerful in immune tolerance and might inhibit/suppress immune cells functions during SARS-CoV2 infection promoting virus subversion. Dosing soluble forms of these molecules in COVID-19 patients’ plasma might help the identification of critical cases. I recommend also developing new SARS-CoV2 therapies based on the use of HLA-G and HLA-E or their specific receptors antibodies in combination with FDA approved therapeutics to combat efficiently COVID-19.     

Role of Toll-like receptor responses for sepsis pathogenesis

Sepsis remains a serious clinical problem because of high patient morbidity and mortality. Despite significant advances in critical care, there is still no efficient causal therapy applicable to patients indicating the need to further elucidate the molecular pathways leading to the immunopathology of sepsis. The importance of Toll-like receptors (TLR) for the induction of immune responses against sepsis was demonstrated in humans exhibiting polymorphisms in TLR genes and in animal models using genetically modified mouse strains. Because of the clinical heterogeneity in human sepsis and the complex pathomechanisms underlying sepsis, several different animal models might be used to cover the diverse features of sepsis. TLR receptors induce signaling through the adapter proteins MyD88 and TRIF. TLR signaling is tightly controlled at different steps of the signaling cascade by series of regulatory proteins. Using a model of severe polymicrobial septic peritonitis we could show that single TLRs are dispensable for the induction of innate immune responses under those conditions. However, genetic ablation of MyD88 or TRIF/type-I interferon signaling pathways prevented hyper-inflammation and attenuated the pathogenic consequences of sepsis indicating that dampening common signaling pathways may create a moderate signal strength which is associated with favorable immune responses. Therefore, broad knowledge about the regulation of TLR-induced signaling pathways may further elucidate the immune mechanisms during sepsis and targeting of TLR adapter molecules may provide a new therapeutic strategy against severe sepsis.     

Role of Toll-like receptor responses for sepsis pathogenesis

Sepsis remains a serious clinical problem because of high patient morbidity and mortality. Despite significant advances in critical care, there is still no efficient causal therapy applicable to patients indicating the need to further elucidate the molecular pathways leading to the immunopathology of sepsis. The importance of Toll-like receptors (TLR) for the induction of immune responses against sepsis was demonstrated in humans exhibiting polymorphisms in TLR genes and in animal models using genetically modified mouse strains. Because of the clinical heterogeneity in human sepsis and the complex pathomechanisms underlying sepsis, several different animal models might be used to cover the diverse features of sepsis. TLR receptors induce signaling through the adapter proteins MyD88 and TRIF. TLR signaling is tightly controlled at different steps of the signaling cascade by series of regulatory proteins. Using a model of severe polymicrobial septic peritonitis we could show that single TLRs are dispensable for the induction of innate immune responses under those conditions. However, genetic ablation of MyD88 or TRIF/type-I interferon signaling pathways prevented hyper-inflammation and attenuated the pathogenic consequences of sepsis indicating that dampening common signaling pathways may create a moderate signal strength which is associated with favorable immune responses. Therefore, broad knowledge about the regulation of TLR-induced signaling pathways may further elucidate the immune mechanisms during sepsis and targeting of TLR adapter molecules may provide a new therapeutic strategy against severe sepsis.     

一种SARS冠状病毒诊断基因芯片的研制

通过筛选SARS冠状病毒的基因序列，获得其有效检测的基因位点；利用已有的基因芯片技术，研制了一张用于SARS冠状病毒诊断的基因芯片。经临床标本检测验证，该基因芯片的粗符合率达到94．29％；检测灵敏度达到10^-2／ml病毒分子，具有很好的实用性。     

Manipulating both the inhibitory and stimulatory immune system towards the success of therapeutic vaccination against chronic viral infections

Summary: One potentially promising strategy to control chronic infections such as human immunodeficiency virus, hepatitis B virus, and hepatitis C virus is therapeutic vaccination, which aims to reduce persisting virus by stimulating a patient's own antiviral immune responses. However, this approach has fallen short of expectations, because antiviral T cells generated during chronic infections often become functionally exhausted and thus do not respond properly to therapeutic vaccination. Therefore, it is necessary to develop a therapeutic vaccine strategy to more effectively boost endogenous T-cell responses to control persistent viral infections. Studies to elucidate the cause of impaired T-cell function have pointed to sustained inhibitory receptor signaling through T-cell expression of programmed death 1 (PD-1). Recently, another inhibitory molecule, cytotoxic T lymphocyte antigen 4 (CTLA-4), and also an immunosuppressive cytokine, interleukin 10 (IL-10), have been reported to be potential factors of establishing immune suppression and viral persistence. Blocking these negative signaling pathways could restore the host immune system, enabling it to respond to further stimulation. Indeed, combining therapeutic vaccination along with the blockade of inhibitory signals could synergistically enhance functional CD8⁺ T-cell responses and improve viral control in chronically infected mice, providing a promising strategy for the treatment of chronic viral infections. Furthermore, not only the ablation of negative signals but also the addition of stimulatory signals, such as interleukin 2 (IL-2), might prove to be a potentially promising strategy to augment the efficacy of therapeutic vaccination against chronic viral infections.