斑马鱼myd88和traf6真核表达载体的构建

髓样分化因子88(myeloid differentiation primary response gene 88,MYD88)和 TNF 受体相关因子6(TNF receptor associated factor 6,TRAF6)均属于 Toll 样受体(Toll-like receptors,TLR)家族成员中的关键衔接分子.斑马鱼是研究先天免疫应答的独特模式生物,为了构建myD88和traf6的真核表达载体,用于免疫应答机制的研究,克隆了斑马鱼myd88和traf6基因的编码区CDS全长序列,分别是855 bp和1 629 bp.结构分析表明,斑马鱼MYD88存在2个保守结构域为死亡结构域和TIR结构域,TRAF6存在4个保守结构域分别为RING结构域、2个锌指结构域、环-环(coiled-coil)结构域以及TRAF同源结构域(meprinand TR-AF-homology,MATH),并与其他物种氨基酸序列一致性较高.系统进化树分析发现斑马鱼myd88和traf6基因与硬骨鱼类亲缘关系较近,说明斑马鱼myd88和traf6基因的同源性符合其在物种进化上的地位并且具有很高的结构同源性.将斑马鱼myd88和traf6基因的CDS全长序列连接至pCMV-Tag2B表达载体.通过对重组质粒进行双酶切检测发现,成功克隆了斑马鱼pCMV-myd88和pCMV-traf6真核表达载体.为了验证这2个真核表达载体的生物学功能,本研究在HEK293T细胞中进行NF-κB的报告基因活性检测.结果表明,过表达myd88和traf6基因后,斑马鱼NF-κB家族nfκbl启动子的转录活性显著升高,分别约为空载对照组的2.5倍和8倍.鉴于MYD88和TRAF6在天然免疫功能等方面的重要作用,实验结果为以后研究斑马鱼的先天免疫信号传导过程提供了有力的研究工具.     

松江鲈(Trachiderm usfasciatus)髓样分化因子MyD88基因克隆与组织表达分析

髓样分化因子(My D88)是TOLL样受体介导的信号通路中的一个关键接头分子,通过激活核转录因子(nuclear factor-kappa B,NF-κB)而参与机体的先天免疫。克隆了松江鲈的My D88基因(命名为Tf My D88),并对该基因进行了生物信息学和表达模式分析。结果显示,Tf My D88 c DNA序列全长1 555 bp,5'UTR长89 bp,3'UTR长599 bp;开放阅读框长度为867 bp,编码288个氨基酸。SMART软件预测Tf My D88分子的N端为一个保守的死亡结构域(death domain,DD),C端存在典型的TIR(Toll/interleukin-1 receptor)结构域。Tf My D88与其它脊椎动物My D88的氨基酸相似性达57.58%-82.64%,系统进化树分析表明Tf My D88与同属鲈形总目的花鲈和鳜鱼聚在一起,所有鱼类My D88聚为一支。Real-time PCR检测显示Tf My D88广泛表达于松江鲈各组织,但在鳃中的相对表达量最高;其次为脾脏和皮肤。LPS(lipopolysaccharide)刺激后,Tf My D88在松江鲈的血液、肝脏、皮肤、脾脏均出现明显上调。刺激2 h后,在血液Tf My D88表达量升高了近60倍,在皮肤中的表达量也升高了27倍。上述结果表明Tf My D88可能参与松江鲈先天免疫。     

胰腺癌患者循环肿瘤细胞及TLR4、TLR9、myd88的表达水平与其化疗效果及转移、复发的关系

目的:探讨胰腺癌患者循环肿瘤细胞(CTC)中Toll样受体4(TLR4)、Toll样受体9(TLR9)、髓样分化因子88(myd88)的表达水平与患者化疗效果及转移、复发的关系。方法:将我院2015年6月-2016年6月收治并确诊的48例胰腺癌患者作为试验组,收集患者循环肿瘤细胞(CTC),检测其TLR4、TLR9、myd88信号表达情况,探讨其TLR4、TLR9、myd88信号表达水平与患者化疗效果及转移、复发的关系。结果:48例胰腺癌患者检出CTC 35例,检出率为72.9%。胰腺癌死亡、转移、复发患者TLR4、TLR9、myd88表达水平分别高于其存活、未转移、未复发患者,组间具有统计学差异(P0.05)。胰腺癌化疗效果CR患者TLR4、TLR9、myd88表达水平显著低于其化疗效果PR、SD、PD患者,且四组间差异具有统计学意义(P0.05);TLR4、TLR9、myd88表达水平与被膜受侵犯、淋巴结转移、肿瘤大小、CA199水平呈正相关(P0.05)。结论:胰腺癌患者CTC中TLRs/myd88信号表达水平与患者化疗效果及转移、复发密切相关。     

七鳃鳗Lja-SHP2分子鉴定、重组表达及免疫学研究

高等脊椎动物的蛋白酪氨酸磷酸酶SHP2(SH2 domain-containing protein-tyrosine phosphatase-2)由ptpn11基因编码,催化酪氨酸残基去磷酸化,与其他能催化酪氨酸磷酸化的蛋白酪氨酸激酶共同调节机体内多种信号通路的信号传导。以往研究表明,SHP2在高等脊椎动物T细胞和B细胞的激活与信号转导过程中起着重要作用。为了研究无颌类脊椎动物日本七鳃鳗(Lampetra japonica)中与SHP2同源的分子——Lja-SHP2在免疫应答反应中的作用,本研究通过PCR扩增获取其Lja-SHP2开放阅读框序列,并构建到原核表达载体pET-32a中,成功在大肠杆菌中实现重组蛋白表达并制备了其兔源多克隆抗体。用混合菌免疫刺激日本七鳃鳗后,通过实时荧光定量PCR和免疫印迹方法检测了Lja-SHP2在日本七鳃鳗免疫相关组织中mRNA和蛋白水平表达谱。结果显示,混合菌免疫刺激后,Lja-SHP2 mRNA和蛋白表达在外周血白细胞和髓样小体中无显著变化,而在鳃组织中显著性上调(P<0.05),说明Lja-SHP2在混合菌刺激后主要参与了鳃组织的免疫应答反应。为了进一步探究Lja-SHP2与淋巴细胞亚群免疫应答反应的相关性,本研究分别使用B细胞有丝分裂原脂多糖(lipopolysaccharide,LPS)和T细胞的有丝分裂原植物凝集素(phytohemagglutinin,PHA)免疫刺激日本七鳃鳗。经LPS免疫刺激后,与对照组相比,白细胞中Lja-SHP2蛋白表达显著上调,鳃组织和髓样小体没有显著性差异表达;但经PHA免疫刺激后,与对照组相比,白细胞、鳃组织和髓样小体3种组织中Lja-SHP2均有上调,尤其在白细胞中上调最为显著,大约是对照组的2.5倍,说明Lja-SHP2参与了日本七鳃鳗由PHA介导的免疫应答反应。由于PHA能刺激日本七鳃鳗鳃组织中VLRA+淋巴细胞的活化,这表明Lja-SHP2可能参与了PHA介导的VLRA+淋巴细胞亚群的免疫应答反应。上述研究结果为进一步探索Lja-SHP2在七鳃鳗免疫应答过程中的功能奠定了基础,也为揭示SHP2分子家族的系统发生及探索高等脊椎动物适应性免疫系统的早期发生及其进化历程提供一定的线索。     

TLR9介导的Myd88信号通路分子在稽留流产患者绒毛组织中的表达及其临床意义

目的:研究TLR9介导的Myd88信号通路在稽留流产患者绒毛组织中的表达及其临床意义。方法:本研究收集了稽留流产患者及正常分娩者的绒毛组织,采用Real-time-PCR及Western-blot方法检测了TLR9介导Myd88信号通路中TLR9、Myd88、TNF-a、NF-κB、IRF1 mRNA和蛋白表达。结果:与正常对照组相比较,TLR9、Myd88、TNF-a、NF-κB、IRF1 mRNA和蛋白在稽留流产组患者绒毛组织中相对表达水平显著升高,差异有统计学意义(P0.05)。结论:稽留流产的发生与TLR9/Myd88信号通路有关。     

七鳃鳗p38α和β参与LPS介导的VLRB类淋巴细胞亚群的免疫应答反应

p38MAPK是丝裂原活化蛋白激酶（mitogen activated protein kinases,MAPK）家族的一个亚类,在高等脊椎动物免疫应答的信号转导过程中扮演着非常重要的角色。在日本七鳃鳗（Lampetra japonica）中发现,p38MAPK以两种异构体的形式存在。通过克隆它们的开放阅读框并进行同源序列比对和系统发育分析,鉴定它们分别为p38α（Lja-mapk14）和p38β（Lja-mapk11）。用混合菌刺激七鳃鳗,利用免疫印迹方法,检测Lja-mapk14在外周血类淋巴细胞、鳃组织和髓样小体中,分别在加强免疫36 h、24 h和24 h后,表达量达到峰值,分别为对照组的2.9、2.1和2.6倍;而Lja-mapk11在以上组织中,都在加强免疫36 h后达到表达量峰值,分别为对照组的2.2、2.5和6.3倍。实时荧光定量PCR检测发现,Lja-mapk14的mRNA表达水平在混合菌加强免疫36 h后,分别在类淋巴细胞、鳃组织和髓样小体中,上调2.3、1.5和3.4倍;而Lja-mapk11的则分别在类淋巴细胞、鳃组织和心肌中,上调1.3、2.6和1.6倍。以上结果在mRNA和蛋白质水平证明,Lja-mapk14和Lja-mapk11均参与七鳃鳗的免疫应答反应。采用B细胞和T细胞丝裂原LPS和PHA分别对七鳃鳗进行刺激,免疫印迹结果显示,Lja-mapk14和Lja-mapk11蛋白质表达量经LPS加强免疫36 h后,在类淋巴细胞、鳃组织和髓样小体中,上调表达1.3 ～ 4.1倍;而经PHA加强免疫36 h后,Lja-mapk14和Lja-mapk11在上述组织中表达量均不存在显著变化。以上结果说明,Lja-mapk14和Lja-mapk11可能参与了B细胞丝裂原LPS介导的VLRB类淋巴细胞亚群的免疫应答反应。     

七鳃鳗p38α和β参与LPS介导的VLRB类淋巴细胞亚群的免疫应答反应

p38MAPK是丝裂原活化蛋白激酶（mitogen activated protein kinases,MAPK）家族的一个亚类,在高等脊椎动物免疫应答的信号转导过程中扮演着非常重要的角色。在日本七鳃鳗（Lampetra japonica）中发现,p38MAPK以两种异构体的形式存在。通过克隆它们的开放阅读框并进行同源序列比对和系统发育分析,鉴定它们分别为p38α（Lja-mapk14）和p38β（Lja-mapk11）。用混合菌刺激七鳃鳗,利用免疫印迹方法,检测Lja-mapk14在外周血类淋巴细胞、鳃组织和髓样小体中,分别在加强免疫36 h、24 h和24 h后,表达量达到峰值,分别为对照组的2.9、2.1和2.6倍;而Lja-mapk11在以上组织中,都在加强免疫36 h后达到表达量峰值,分别为对照组的2.2、2.5和6.3倍。实时荧光定量PCR检测发现,Lja-mapk14的mRNA表达水平在混合菌加强免疫36 h后,分别在类淋巴细胞、鳃组织和髓样小体中,上调2.3、1.5和3.4倍;而Lja-mapk11的则分别在类淋巴细胞、鳃组织和心肌中,上调1.3、2.6和1.6倍。以上结果在mRNA和蛋白质水平证明,Lja-mapk14和Lja-mapk11均参与七鳃鳗的免疫应答反应。采用B细胞和T细胞丝裂原LPS和PHA分别对七鳃鳗进行刺激,免疫印迹结果显示,Lja-mapk14和Lja-mapk11蛋白质表达量经LPS加强免疫36 h后,在类淋巴细胞、鳃组织和髓样小体中,上调表达1.3 ～ 4.1倍;而经PHA加强免疫36 h后,Lja-mapk14和Lja-mapk11在上述组织中表达量均不存在显著变化。以上结果说明,Lja-mapk14和Lja-mapk11可能参与了B细胞丝裂原LPS介导的VLRB类淋巴细胞亚群的免疫应答反应。     

奥利亚罗非鱼髓样分化因子(MyD88)的克隆及其在组织中的表达

髓样分化因子（myeloid differentiation factor 88,MyD88）是TLR（toll-like receptor）信号通路的关键接头蛋白,在先天性免疫中具有重要作用。通过RACE-RCR技术克隆了奥利亚罗非鱼（Oreochromis aureus）MyD88基因cDNA全长序列（GenBank登录号：JN032017）。序列分析表明,奥利亚罗非鱼MyD88 基因全长为1 611 bp,其中包括155 bp的5’非编码区,589 bp的3’非编码区和867 bp的编码区,编码288个氨基酸残基。MyD88蛋白N端具有死亡结构域,C端具有TIR结构域。同源性分析表明,奥利亚罗非鱼MyD88氨基酸序列与鳜鱼（Siniperca chuats）相似性最高,为85.8%,与其他鱼类相似性为70%~82%,与哺乳动物相似性为63%~66%;系统进化树分析表明,奥利亚罗非鱼MyD88与同属鲈形目的鳜鱼、大黄鱼（Larimichthys crocea）聚在一起。采用实时定量PCR方法检测MyD88在奥利亚罗非鱼各组织中的表达情况。结果显示,MyD88在所有被测组织中都有表达,其中表达量最高的是卵巢,其次在小肠、脾、肝、肾、鳃和血液中有较高的表达量,肌肉、精巢组织中表达量最低。本研究可为进一步探讨MyD88在奥利亚罗非鱼TLR信号通路中的作用奠定一定的基础。     

分子氢对糖尿病视网膜小胶质细胞的保护作用及其机制研究

目的:研究分子氢对糖尿病视网膜小胶质细胞的保护作用及其可能机制。方法:采用100 ng/m L的LPS诱导视网膜小胶质细胞,同时将两组细胞分别置于正常培养环境和含有饱和氢培养环境下培养36小时。RT-PCR检测小胶质细胞中miR-9、miR-21和miR-199的表达。Western Blot测定TLR4信号途径相关蛋白的表达。结果:miR-9、miR-21在分子氢作用后明显下调,而miR-199在分子氢作用后下调不明显。并且,小胶质细胞活化后TLR4途径相关信号蛋白的表达增加,在分子氢处理后Myd88和IKKβ蛋白的表达明显减少,而NF-κB蛋白的表达前后没有明显的变化。结论:分子氢对视网膜小胶质细胞的炎症损伤具有明显的保护作用,氢作为一种信号分子对Myd88介导的TLR4炎症信号通路的调节及通路中部分miRNA的调节作用可能是其抗炎作用的机制。     

miR-29a对于膝关节骨性关节炎大鼠滑膜损伤中的保护作用研究

摘要 目的：探讨miR-29a对于膝关节骨性关节炎（KOA）大鼠滑膜损伤中的保护作用研究。方法：采用前交叉韧带横断法（ACLT）建立KOA大鼠模型。大鼠注射microRNA阴性对照和miR-29a。通过实时定量聚合酶链反应（RT-qPCR）检测KOA滑膜组织和滑膜细胞中miR-29a的表达。RT-qPCR和蛋白免疫印迹试验检测Toll样受体4/髓样分化蛋白88/核因子κB（TLR4/Myd88/NF-κB）信号通路相关蛋白的表达。检测KOA滑膜组织及滑膜细胞中炎症因子的表达水平。结果：KOA滑膜组织和滑膜细胞中miR-29a表达下调。上调miR-29a可抑制KOA大鼠滑膜细胞的炎症反应,促使KOA大鼠的TLR4/Myd88/NF-κB信号通路失活。结论：上调miR-29a可通过TLR4/Myd88/NF-κB信号通路失活化抑制KOA大鼠滑膜细胞炎症反应,从而保护滑膜损伤。     

Molecular cloning and expression analysis of myd88 from oriental weatherfish (Misgurnus anguillicaudatus) in response to bacterial challenge

Myeloid differentiation factor 88 (Myd88) plays an important role in both innate and adaptive immune response. In this study, the full-length complementary DNA (cDNA) of myd88 from Misgurnus anguillicaudatus was characterized. The myd88 cDNA is 1333 bp in length and contains an 855 bp open reading frame encoding a predicted protein of 284 amino acids. The predicted protein possesses typical Myd88 domain structural features including a death domain in the N-terminus, and box 1, 2, and 3 motifs of the Toll/IL-1 receptor domain in the C-terminus. Quantitative real-time PCR (qRT-PCR) revealed that myd88 messenger RNA (mRNA) was ubiquitously expressed in all examined tissues, especially highly in brain, kidney, blood, intestines and liver. qRT-PCR and western blotting were used to determine the mRNA and protein levels of Myd88 after Aeromonas veronii challenge, respectively. The Myd88 was remarkably upregulated in response to infection of A. veronii. These results suggested that Myd88 may play a vital role during the immune response of M. anguillicaudatus against bacterial infection.     

Identification and characterization of a myeloid differentiation factor 88 (MyD88) cDNA from Zhikong scallop Chlamys farreri

Myeloid differentiation factor 88 (MyD88) is a universal and essential adapter for the TLR/IL-1R family. In this report, the first mollusk Myd88 ortholog (named as CfMyd88) was cloned from Zhikong scallop (Chlamys farreri). The full-length cDNA of CfMyd88 was of 1554 bp, including a 5'-terminal untranslated region (UTR) of 427 bp, a polyA tail, and an open reading frame (ORF) of 1104 bp encoding a polypeptide of 367 amino acids containing the typical TLR and IL-1R-related (TIR) domain and death domain (DD). Homology analysis revealed that the predicted amino acid sequence of CfMyd88 was homologous to a variety of previously identified Myd88s with more than 30% identity. The temporal expressions of CfMyd88 mRNA in the mixed primary cultured haemocytes stimulated by lipopolysaccharide (LPS) and peptidoglycans (PGN) were measured by real-time RT-PCR system. The mRNA expression of CfMyd88 decreased after stimulation with both LPS and PGN, and the lowest level was about 1/3 times (at 6 h) and 1/10 times (at 9 h) to that in the control group, respectively. The expression then recovered and was upregulated to two-fold at 9 h after LPS stimulation or to the original level at 12 h after PGN stimulation. The results suggest that the MyD88-dependent signaling pathway exists in scallop and was involved in the defense system.     

Characterization of a novel molluscan MyD88 family protein from manila clam, Ruditapes philippinarum

Myeloid differentiation factor 88 (MyD88) is a universal adaptor protein which is required for signal transduction of TLR/IL-1R family. In this study, a novel molluscan MyD88 family member protein (named as RpMyD88) was identified from manila clam, Ruditapes philippinarum. It was identified using BLAST algorithm from GS-FLX? sequencing data. The cDNA of RpMyD88 consists of 1416 bp open reading frame (ORF) encoding 471 amino acid residues. The RpMyD88 contains death domain and Toll/interleukin-1 receptor (TIR) domain which are typical features of MyD88 family proteins. The predicted amino acid sequence of RpMyD88 shares 27% identity with scallop MyD88. The expression level of RpMyD88 mRNA was investigated in healthy and challenged clams by quantitative real-time RT-PCR. The RpMyD88 gene expression is ubiquitous in all selected tissues. The RpMyD88 mRNA was strongly expressed in hemocyte, gill and mantle. In contrast, it was weakly expressed in siphon, foot and adductor muscle. RpMyD88 was up-regulated in gill and hemocyte after immune challenge with both Vibrio tapetis and LPS challenge. All results considered, sequence characterization, comparison and gene expression data suggesting that MyD88-dependent signaling pathway is presence in manila clam and RpMyD88 plays an important role in innate immune response against bacteria.     

Myd88-dependent toll-like receptor 7 signaling mediates protection from severe ross river virus-induced disease in mice

Arthralgia-associated alphaviruses, including chikungunya virus (CHIKV) and Ross River virus (RRV), pose significant public health threats because of their ability to cause explosive outbreaks of debilitating arthralgia and myalgia in human populations. Although the host inflammatory response is known to contribute to the pathogenesis of alphavirus-induced arthritis and myositis, the role that Toll-like receptors (TLRs), which are major regulators of host antiviral and inflammatory responses, play in the pathogenesis of alphavirus-induced arthritis and myositis has not been extensively studied. Using a mouse model of RRV-induced myositis/arthritis, we found that myeloid differentiation primary response gene 88 (Myd88)-dependent TLR7 signaling is involved in protection from severe RRV-associated disease. Infections of Myd88- and TLR7-deficient mouse strains with RRV revealed that both Myd88 and TLR7 significantly contributed to protection from RRV-induced mortality, and both mouse strains exhibited more severe tissue damage than wild-type (WT) mice following RRV infection. While viral loads were unchanged in either Myd88 or TLR7 knockout mice compared to WT mice at early times postinfection, both Myd88 and TLR7 knockout mice exhibited higher viral loads than WT mice at late times postinfection. Furthermore, while high levels of RRV-specific antibody were produced in TLR7-deficient mice, this antibody had very little neutralizing activity and had lower affinity than WT antibody. Additionally, TLR7- and Myd88-deficient mice showed defects in germinal center activity, suggesting that TLR7-dependent signaling is critical for the development of protective antibody responses against RRV.     

Characterization analysis and polymorphism detection of the porcine Myd88 gene

The myeloid differentiation primary response protein 88 (Myd88) is an essential adaptor protein, which mediates in all Toll-like receptor (TLR) members signal transduction, except for TLR3. In this study, the 4464 bp genomic sequence of porcine Myd88 was first isolated, whereupon tissue distribution, chromosome mapping and single nucleotide polymorphism (SNP) were analyzed. Our results revealed that porcine Myd88 gene, which was located at chromosome 13 linked with marker S0288 (distance = 40 cR; LOD = 8.66), was widely expressed in all the examined tissues. There were 16 potential SNPs in the isolated genome fragment. SNP 797T/C in the first intron was studied, with no significant association being found between the genotype and immune traits in pigs (p > 0.05). The porcine Myd88 protein contained both the death domain (DD) and the Toll/IL-1 receptor domain (TIR). Leu residues, essential for its structure, were the most abundant encountered in the DD. The TIR contained two conserved motifs which may play important roles in the Myd88 function.     

Protective effect of resveratrol against LPS-induced extracellular lipoperoxidation in AR42J cells partly via a Myd88-dependent signaling pathway

Lipopolysaccharides (LPS) are major components of the cell wall of Gram negative bacteria implicated in the pathogenesis of bacterial infection. Resveratrol is a polyphenolic phytoalexin exhibiting antioxidant and anti-inflammatory properties. We investigated the protective effects of this natural compound on LPS-induced proinflammatory effect using non-myeloid AR42J pancreatic cells. We found that LPS dose-dependently increased extracellular malondialdehyde (MDA) and nitric oxide without affecting their intracellular level whereas resveratrol abolished all these deleterious effects. LPS increased CD14 expression; IRAK1 and a phosphorylated form of p38 MAPK protein. Resveratrol counteracted LPS effect by decreasing CD14 and IRAK1 expression but unexpectedly increased the p38 MAPK protein phosphorylation. Altogether, our data highlighted the functionality of the TLR4-Myd88 signaling pathway in LPS pro-oxidant effect using non-myeloid cells. They further suggested that resveratrol exerted antioxidant properties either by a Myd88-dependent way not involving IRAK1 or by a TRIF dependent pathway.     

Lipopolysaccharide stimulates the MyD88-independent pathway and results in activation of IFN-regulatory factor 3 and the expression of a subset of lipopolysaccharide-inducible genes.

Bacterial lipopolysaccharide (LPS) triggers innate immune responses through Toll-like receptor (TLR) 4, a member of the TLR family that participates in pathogen recognition. TLRs recruit a cytoplasmic protein, MyD88, upon pathogen recognition, mediating its function for immune responses. Two major pathways for LPS have been suggested in recent studies, which are referred to as MyD88-dependent and -independent pathways. We report in this study the characterization of the MyD88-independent pathway via TLR4. MyD88-deficient cells failed to produce inflammatory cytokines in response to LPS, whereas they responded to LPS by activating IFN-regulatory factor 3 as well as inducing the genes containing IFN-stimulated regulatory elements such as IP-10. In contrast, a lipopeptide that activates TLR2 had no ability to activate IFN-regulatory factor 3. The MyD88-independent pathway was also activated in cells lacking both MyD88 and TNFR-associated factor 6. Thus, TLR4 signaling is composed of at least two distinct pathways, a MyD88-dependent pathway that is critical to the induction of inflammatory cytokines and a MyD88/TNFR-associated factor 6-independent pathway that regulates induction of IP-10.