NOD1/2介导的信号通路及其抗病原微生物免疫应答的研究进展

NOD1/2蛋白为胞质内的模式识别受体,识别进入胞内的细菌胞壁及其降解产物,介导NF-κB和丝裂原活化蛋白激酶(MAPK)信号途径。NOD1受体还通过干扰素刺激基因因子3(ISGF3)信号途径诱导产生1型干扰素,NOD2受体能识别ssRNA和病毒基因组ssRNA,通过线粒体抗病毒信号蛋白(MAV)信号途径而激活干扰素调节因子3(IRF3)。它们分别参与了抗细菌、抗病毒、抗寄生虫等病原微生物免疫应答。对NOD1和NOD2受体的进一步认识,为研究相关病原感染和慢性炎症性疾病的防治措施提供了新的思路。     

胞壁酰二肽激活小鼠原代肝窦内皮细胞中NOD2信号

目的调查小鼠原代肝窦内皮细胞(liver sinusoidal endothelial cells,LSECs)中NOD2信号通路激活后产生的免疫应答效应。方法使用胶原酶灌注方法结合percoll密度梯度离心加抗小鼠LSEC免疫磁珠分离纯化小鼠LSEC。定量PCR检测小鼠原代LSEC NOD1和NOD2 mRNA表达水平,同时给胞壁酰二肽刺激小鼠原代LSEC;定量PCR检测NOD2、RIP2、TNF-α和IL-6mRNA表达水平;定量ELISA检测细胞上清IL-6和TNF-α蛋白产量。结果小鼠原代LSEC中NOD2基础表达水平相对于NOD1基础表达水平较低。胞壁酰二肽刺激LSEC后诱导NOD2及其下游分子RIP2表达水平上调,接着诱导产生IL-6效应分子,而没有诱导产生TNF-α等其它细胞因子和趋化因子。结论胞壁酰二肽能够激活小鼠LSEC中NOD2介导的信号通路,并诱导产生IL-6效应分子,可能在维持肝脏内环境稳定中发挥着重要作用。     

NOD 蛋白与免疫应答

NOD 蛋白包括NOD1 和NOD2,两者识别细菌肽聚糖的片段,诱导促炎和抗菌反应。在本篇综述中,我们介绍 近年来NOD 蛋白的研究进展,包括激活的方式,信号途径的调节,在细胞中的定位以及在免疫防御过程中发挥的作用。洞悉 NOD 蛋白诱导的信号通路有助于了解相关疾病的致病机理,为疾病的治疗提供新的视角。     

接头蛋白STING介导信号通路在抗病毒感染中的研究进展

干扰素基因刺激蛋白(stimulator of interferon gene,STING)是一种介导胞内DNA诱导固有免疫应答的重要接头蛋白,在机体抗病毒免疫反应中起关键作用。宿主细胞通过模式识别受体(pattern recognition receptor,PRR)识别入侵病原体的DNA,将信号传递给STING,导致TANK连接激酶1(TANK-binding kinase 1,TBK1)和干扰素调控因子3(interferon regulatory factor 3,IRF3)磷酸化,从而促进Ⅰ型IFN的上调表达,进而抑制病毒复制。文章介绍了STING分子的结构、转导通路以及分子调控机制,重点概述STING介导的信号通路在抗病毒感染中的作用以及病毒对该信号通路的调控机制,以期为抗病毒药物的研究提供新的靶点和思路。     

NOD1、NOD2:两个重要的天然免疫胞内识别受体

机体对微生物入侵的免疫炎症应答过程中模式识别受体(patternrecognitionreceptors,PRRs)是启动机体天然免疫应答机制的关键,主要在获得性免疫系统被活化之前发挥抗感染作用。NOD1和NOD2这两个蛋白分子作为一种新的胞内识别受体参与了细胞凋亡和核因子NF-κB的活化,并与一些炎症性疾病密切相关,在天然免疫中发挥了重要的作用。     

模式识别受体视黄酸诱导基因-Ⅰ样受体及信号通路研究进展

视黄酸诱导基因-I样受体(RLRs)是近年来发现的一类重要的模式识别受体。它能够通过识别病毒核酸如5’-三磷酸化的ssRNA和与长度相关的dsRNA,激活IPS-1、MITA等一系列信号分子,通过NF-kB和IRF-3/7两条通路引起I型干扰素等细胞因子的表达,进而发挥抗病毒效应。机体可通过多种调控因子对RLRs信号通路进行精细调控。RLRs信号通路对于理解机体抗病毒固有免疫应答具有重要价值。     

NOD1,NOD2和NLRP3炎症小体与牙髓炎

模式识别受体(pattern recognition receptors,PRRs)识别病原相关分子模式(pathogen associated molecule patterns,PAMP)激活固有免疫系统,是抵抗病原微生物入侵的第一道防线.核苷酸结合寡聚化结构域蛋白(nucleotide-binding oligomerization domains,NODs)和NOD样受体蛋白3(NODlike protein 3,NLRP3)属胞质内PRRs家族.NOD1和NOD2激活NF-κB,MAPK,JNK,p38和ERK信号通路,促进TNF-α,IL-1β,IL-6,IL-8和IL-12等多种炎性因子的转录表达.NLRP3炎症小体激活caspase-1,并促进IL-18和IL-1β表达.牙髓位于低顺应性根管系统中,牙髓环境环境与机体其他组织不同.目前的研究表明NOD1,NOD2和NLRP3炎症小体与牙髓固有免疫及牙髓炎的发生、发展有关.     

NOD小鼠胸腺细胞TCR介导的信号通路缺陷

目的 进一步研究NOD小鼠T细胞应答改变机理。方法 用抗TCR抗体、ConA激活NOD小鼠胸腺细胞，分析TCR介导的信号通路的水平。结果 与Balb／c小鼠胸腺细胞相比，抗TCR抗体诱导的增殖应答较弱，与年龄及NOD胸腺CD4^ CD8^-和CD4^-CD8^ SP细胞有关；rIL-2能部分恢复对TCR抗体应答的缺乏。NOD小鼠对PMA IONO和PMA anti—TCR-mAb应答正常，但对anti-TCRmAb IONO应答缺乏。结论 与年龄有关的NOD小鼠胸腺细胞对TCR抗体应答的缺乏与T细胞激活时上游PKC信号通路的缺乏有关。     

细胞内模式识别受体NOD2蛋白的研究进展(文献综述)

先天性免疫是机体抵抗病原微生物入侵的第一道屏障,动物的先天性免疫主要通过模式识别受体（PRRs）识别病原体相关分子模式（PAMPs）来实现的。TOLL样受体和NOD（nucleotide—binding oligomerzation domain,NOD）蛋白是代表哺乳类动物两类典型的模式识别受体。其中NOD蛋白是一种胞浆内的模式识别受体,其家族主要代表成员为NOD1和NOD2。TOLL样受体是胞膜内受体。均参与机体的天然免疫应答,是连接天然免疫和获得性免疫的桥梁。现就NOD2蛋白与抗感染免疫的研究进展作一综述。     

固有免疫中TLR和NOD的研究现状

固有免疫是机体防御感染性疾病的第一道防线.随着模式识别理论的提出和Toll样受体(TLR),细胞质内的核苷酸结合寡聚化结构城(NOD)的发现,为了解机体识别细菌和炎症防御机制方面开阔了视野.了解TLR和NOD的结构、表达、分布和信号途径,相互影响和与疾病的关系以及研究TLR和NOD的意义很重要.     

NOD1和NOD2:介导天然免疫的两种胞浆蛋白

NOD1和NOD2是新发现的一类参与天然免疫的胞浆蛋白质家族--核苷酸结合寡聚域样受体(the nucleotide binding oligomerization domain-like receptor, NLRs)中的两个重要蛋白受体,它们通过识别外源病原菌的模式抗原分子而激活NF-κB等核转录因子,启动相关细胞因子的基因表达,释放炎性因子和抗菌肽等, 其介导的信号通路在宿主抵御病原体感染的天然免疫中发挥着重要作用.     

NOD1 and NOD2 in inflammatory and infectious diseases

It has been long recognized that NOD1 and NOD2 are critical players in the host immune response, primarily by their sensing bacterial peptidoglycan-conserved motifs. Significant advances have been made from efforts that characterize their upstream activators, assembly of signaling complexes, and activation of downstream signaling pathways. Disruption in NOD1 and NOD2 signaling has also been associated with impaired host defense and resistance to the development of inflammatory diseases. In this review, we will describe how NOD1 and NOD2 sense microbes and cellular stress to regulate host responses that can affect disease pathogenesis and outcomes.     

NOD1 and NOD2 regulation of pulmonary innate immunity to Legionella pneumophila

The role of nucleotide‐binding oligomerization domain‐1 (NOD1) and nucleotide‐binding oligomerization domain‐2 (NOD2), cytoplasmic receptors which detect bacterial cell wall molecules, in pulmonary innate immune responses is poorly understood. We determined that both NOD1 and NOD2 detect heat‐killed Legionella and stimulate NF‐κb and IFN‐β promoter activity using an in vitro luciferase reporter system. We next infected NOD1‐ and NOD2‐deficient animals with aerosolized Legionella pneumophila. At 3 days post infection, Nod1^?/? mice had impaired bacterial clearance compared to WT controls. In addition, at 4 h and 24 h, Nod1^?/? mice had impaired neutrophil recruitment to the alveolar space. In contrast, increased lung neutrophils were seen in the Nod2^?/? animals at 24 h. Analysis of cytokine production at 4 h post infection revealed a significant decrease in proinflammatory cytokines in the Nod1^?/? animals when compared to WT animals. In contrast, increased 4‐h proinflammatory cytokines were seen in the Nod2^?/? animals. Furthermore, the lungs of both Nod1^?/? and Nod2^?/? mice had significantly increased pro‐inflammatory cytokine levels at 24 h, suggesting possible suppressive roles for later stages of infection. Together, our data suggest that although both NOD1 and NOD2 can detect Legionella, these receptors modulate the in vivo pulmonary immune response differently.     

Synergistic stimulation of human monocytes and dendritic cells by Toll-like receptor 4 and NOD1- and NOD2-activating agonists

Muropeptides are degradation products of bacterial peptidoglycan (PG) sensed by nucleotide-binding oligomerization domain 1 (NOD1) and NOD2, members of a recently discovered family of pattern recognition molecules (PRM). One of these muropeptides, muramyl dipeptide (MDP) mediates cell signaling by NOD2, exerts adjuvant activity and synergizes with lipopolysaccharide (LPS) to induce pro-inflammatory responses in vitro and in vivo. In contrast, few and contradictory results exist about the stimulatory capacity of NOD1 agonists. Thus, the ability of NOD1 (MurNAc-L-Ala--D-Glu-meso-diaminopimelic acid, MtriDAP) and NOD2 (MurNAc-L-Ala-D-isoGln, MDP; MurNAc-L-Ala--D-Glu-L-Lys, MtriLYS) agonists to activate primary human myeloid cells was examined. We show that both CD14+ monocytes and CD1a+ immature dendritic cells (DC) express NOD1 and NOD2 mRNA. Stimulation of primary human monocytes and DC with highly purified muropeptides (MtriDAP, MDP and MtriLYS) induces release of pro-inflammatory cytokines. We reveal here that NOD1 as well as NOD2 agonists act cooperatively with LPS to stimulate the release of both pro- and anti-inflammatory cytokines in these myeloid cell subsets. Finally, we report that NOD1 as well as NOD2 agonists synergize with sub-active doses of LPS to induce DC maturation, demonstrating that NOD agonists act cooperatively with molecules sensed by Toll-like receptor 4 to instruct the onset of adaptive immune responses.     

The NOD Mouse as a Model of SLE

In addition to developing a high incidence of type 1 diabetes caused by a specific autoimmune response against pancreatic β cells in the islets of Langerhans, NOD mice also demonstrate spontaneous autoimmunity to other targets including the thymus, adrenal gland, salivary glands, thyroid, testis, nuclear components and red blood cells. Moreover, treatment of pre-diabetic NOD mice with an intravenous dose of heat killed Mycobacterium bovis (M. bovis; bacillus Calmette-Guerin (BCG)) protects them from developing type 1 diabetes, but instead precipitates an autoimmune rheumatic disease similar to systemic lupus erythematosus (SLE), characterised by accelerated and increased incidence of haemolytic anaemia (HA), anti-nuclear autoantibody (ANA) production, exacerbation of sialadenitis, and the appearance of immune complex-mediated glomerulonephritis (GN). The reciprocal switching between the two phenotypes by a single environmental trigger (mycobacterial exposure) raised the possibility that genetic susceptibility for type 1 diabetes and SLE may be conferred by a single collection of genes in the NOD mouse. This review will focus on the genetic components predisposing NOD mice to SLE induced by BCG treatment and compare them to previously determined diabetes susceptibility genes in this strain and SLE susceptibility genes in the BXSB, MRL and the New Zealand mouse strains     

Role of NOD1/CARD4 and NOD2/CARD15 gene polymorphisms in cancer etiology

NOD1/CARD4 and NOD2/CARD15 are members of Nod-like receptor family. They are located in cytosol, bind bacterial and viral ligands and play a key role in realization of innate and adaptive immune response, apoptosis, autophagy, and reactive oxygen species generation. Polymorphisms in NOD1/CARD4 and NOD2/CARD15 genes may shift balance between pro- and anti-inflammatory cytokines, modulating the risk of infection, chronic inflammation and cancer. NOD1/CARD4 and NOD2/CARD15 gene polymorphisms may be associated with altered risk of gastric, colorectal, breast, ovarian, prostate, testicular, lung, laryngeal, liver, gallbladder, biliary tract, pancreatic, small bowel, kidney, urinary bladder cancer, skin cancer, nonthyroid endocrine tumors, lymphoma and leukemia. The short list of such polymorphisms perspective for oncogenomic investigations may include rs2006847, rs2066845, rs2066844, rs2066842, ND(1)+32656, rs2075820 whereas rs104895493, rs104895476, rs104895475, rs104895474, rs104895473, rs104895472, rs104895462, rs104895461, rs104895460, rs104895438, rs5743291, rs5743260, rs2076756, rs2066843, Pro371Thr, Ala794Pro, Gln908His, rs72551113, rs72551107, rs6958571, rs2907749, rs2907748, rs2075822, rs2075819, rs2075818 may be added to the extended list. Reasons of discrepancies between different studies include confounding host genetic, bacterial, or environmental factors modulating penetrance of variant allele and affecting risk of condition increasing cancer risk, different bacterial impact in aetiology of such conditions, differences in sample size, clinicopathological characteristics, diagnostics, stratification, genotyping methods, and chance.     

Normal responses to specific NOD1-activating peptidoglycan agonists in the presence of the NOD2 frameshift and other mutations in Crohn's disease

Both NOD2/CARD15 alleles are mutated in approximately 10% of Crohn's disease patients, causing loss of functional responses to low-dose muropeptide agonists. We hypothesized that NOD2 mutations may also impair NOD1/CARD4 responses, supported by data suggesting NOD2 1007fs/1007fs patients had reduced responses to a putative NOD1 agonist, diaminopimelic acid-containing muramyl tripeptide (M-TriDAP). We measured peripheral blood mononuclear cell (n = 8 NOD2 wild type, n = 4 1007fs/1007fs, n = 6 702Trp/1007fs, n = 5 702Trp/702Trp, n = 3 908Arg/1007fs) responses to NOD1 agonists alone (IL-8/TNF-alpha), and agonist enhancement of lipopolysaccharide (LPS) responses (IL-1beta). Significant responses were seen with M-TriDAP at 10 nM (as with NOD2 agonists), but only at > or =100 nM with FK565/TriDAP. M-TriDAP induced IL-8/TNF-alpha secretion, and enhancement of LPS IL-1beta responses was significantly reduced between NOD2 double mutation carriers versus healthy controls, whereas there was no difference with FK565 or TriDAP stimulation, or between 1007fs/1007fs cells and other genotypes. M-TriDAP contains both NOD1 (gamma-D-Glu-mesoDAP) and NOD2 (MurNAc-L-Ala-D-Glu) minimal structures whereas FK565/TriDAP contain only NOD1 activating structures. M-TriDAP has dual NOD1/NOD2 agonist activity in primary cells, possibly due to different intracellular peptidoglycan processing compared to the HEK293 cell system typically used for agonist specificity studies. Responses to specific NOD1 agonists are unaffected by NOD2 genotype, suggesting independent action of the NOD1 and NOD2 pathways.