TLR9的特性及其介导的TLR9/CpG-DNA免疫信号通路

TLRs在天然免疫应答中发挥着重要作用,构成了机体抗感染的第一道防线,是沟通天然免疫和获得性免疫的桥梁。其中TLR9已经被证实能够识别细菌DNA中免疫刺激序列CpG,从而激活哺乳动物细胞的天然免疫机制,这一发现具有重要的生物学意义与应用价值。它不仅进一步推进了外源DNA激活哺乳动物抗感染天然免疫的进一步研究,更为CpG-DNA应用于抗感染、肿瘤和免疫缺陷疾病等的治疗提供新的思路,为改进DNA疫苗效果提供非常有益的帮助。     

TLR9信号通路介导缺血性脑损伤的研究进展

炎症反应是缺血性脑损伤的重要机制之一,过度的炎症免疫反应会加剧脑损伤的程度。作为先天免疫系统的重要组成部分,Toll样受体9(Toll like receptor 9,TLR9)通过识别其特异性的配体Cp G-DNA,从而激活先天免疫系统,释放大量前炎症细胞因子,参与缺血性脑损伤的炎症反应过程。近年来,有学者提出将TLR9作为一个新的缺血预处理靶点,即通过启动TLR9信号转导通路增加体内炎症细胞因子的水平来对抗缺血损伤。本文通过对近年TLR9信号通路介导的炎症反应与缺血性脑损伤相关研究进展作一综述,为寻求临床安全高效的缺血性脑损伤防治措施提供理论依据。     

TLR/MyD88信号通路与自身免疫性疾病

Toll样受体(Toll-like receptor,TLR)是近年来发现的一类模式识别受体,通过识别病原相关分子模式(pathogen-associated molecular pattern,PAMP),激活天然免疫.TLR信号还通过上调抗原提呈细胞(antigen presenting cells,APC)表面共刺激分子及APC分泌的炎症细胞因子调节获得性免疫.TLR/MyD88信号在自身免疫性疾病的发病过程中起重要作用.本文介绍了TLR/MYD88信号通路及其在自身免疫病如实验性自身免疫脑脊髓膜炎、类风湿性关节炎、实验性自身免疫性葡萄膜炎、实验性自身免疫性心肌炎和自身免疫性肾小球肾炎等发生发展中的作用.     

稽留流产患者血清和绒毛中HIF-1alpha和VEGF表达水平及其相关性分析

目的：探讨缺氧诱导因子-1alpha（HIF-1alpha）和血管内皮生长因子（VEGF）在稽留流产患者血清和绒毛中的表达水平及其相关性 分析。方法：选择2014 年8 月至2015 年8 月我院妇产科76 例稽留流产患者为观察组及行人工流产的60 例正常早产孕妇为对 照组;根据患者稽留流产时间将稽留流产患者分为稽留时间<2 周组（12 例）,2~4周组（33 例）,>4周组（31 例）;采用酶联免疫吸 附（ELISA）和免疫组化SP 法检测并分析患者血清与绒毛中HIF-1琢与VEGF的表达水平。结果：观察组血清中HIF-1alpha与VEGF 表达水平均显著低于对照组,差异有统计学意义（P<0.05）;观察组和对照组绒毛VEGF 和HIF-1-alpha均表达,其中VEGF 主要表达 于滋养层细胞细胞质和细胞间质,HIF-1琢主要表达于滋养层细胞的细胞核与细胞质,且观察组患者绒毛HIF-1-alpha与VEGF 表达水 平均显著低于对照组,差异有统计学意义（P<0.05）;不同稽留时间患者绒毛HIF--alpha与VEGF表达水平间比较,差异均无统计学意 义（P>0.05）观察组患者血清HIF-1alpha与VEGF的表达水平呈现正相关关系（r=0.601;P<0.05）;且绒毛HIF-1琢与VEGF的表达水平 也呈现正相关关系（r=0.401;P<0.05）。结论：HIF-1琢和VEGF在血清和绒毛中的低表达可能是稽留流产的发生的重要原因,临床 上可以通过检测患者血清和绒毛组织中HIF-1琢和VEGF的水平,有针对性的对患者进行监护和治疗,预防稽留流产的发生。     

MyD88依赖的TLR4信号通路在无症状HIV阳性患者肺泡巨噬细胞中的选择性损伤

肺泡巨噬细胞（AMS）是肺部主要的效应细胞,可通过模式识别受体如Toll样受体4（TLR4）识别病原微生物,从而发挥关键的第1道防线作用。在人类免疫缺陷病毒（HIV）阳性的巨噬细胞中,     

TLR4及其作用的研究进展

Toll样受体(toll-like receptors,TLRs)因其积极的研究成果而成为近年来广受关注的一种病原体识别受体,TLRs分布相对比较广泛,不但在小肠上皮、呼吸上皮细胞表达,同时也在血管内皮细胞、树突状细胞[1]、大鼠脾及心肌细胞[2]等细胞中表达.研究证实,它属于模式识别受体(pattern recognition receptors,PRRs),病原相关分子模式(pathogen-associated molecule pattern,PAMPs)可被其辨别,然后引发一系列的信号转导,TLRs 是备受关注的一种PRRs.Toll样受体4(toll-like receptor 4,TLR4)是TLRs家族中极为重要的成员,是天然免疫系统识别病原微生物的主要受体,在天然免疫反应中扮演着关键性作用.细菌脂多糖(lipopolysaccharide,LPS)作为一类受体,主要作用是介导信号跨膜转导,尤其对革兰氏阴性菌所引起的感染性炎症起着极为关键的作用.由于近年来对TLR4介导的信号转导及TLR4与疾病的关系研究成为热点,本文就TLR4的信号转导、TLR4与LPS的关系及TLR4信号通路调节进行综述如下.     

TLR5的进化、功能及相关疾病研究

自第一个TLR蛋白被发现以来,越来越多的TLR家族成员逐渐被鉴定出来.TLR5作为TLR家族中的重要一员,是识别鞭毛蛋白的主要胞外受体.所有脊椎动物的TLR5在结构与功能上十分保守,具有典型的TLR结构域,即数量不等的亮氨酸重复序列、跨膜结构域,以及细胞内的Toll/IL-1受体结构域.TLR5仅在鱼类中有两种形式,分...     

TLR介导的信号通路在肝纤维化中的作用

Toll样受体(Toll - like receptor,TLR)是在天然免疫与获得性免疫应答中发挥重要作用的模式识别受体(Pattern recognition receptors,PRRs).TLR识别来源于病原体或机体损伤产生的“危险信号”,介导多种炎症因子释放,激发机体对病原体的免疫反应,启动固有免疫并进一步活...     

鼻咽癌细胞5-8F通过TLR4介导的信号通路对革兰氏阴性细菌脂多糖的反应性研究

鼻咽上皮细胞无时无刻不暴露和接触到共生微生物与病原微生物,机体依靠天然防御系统和抗原识别的适应性免疫反应系统来进行自我保护.慢性感染的重要毒力因素被认为是革兰氏阴性细菌细胞壁的主要成分脂多糖(LPS),对LPS的识别与信号传导是宿主细胞抵御革兰氏阴性细菌的关键.通过流式细胞术、RT-PCR等研究发现,5-8F细胞可与LPS相结合并产生反应,且其受LPS调节的机制是由于5-8F细胞中存在LPS受体分子如CD14、TLR4与MD2等的表达.同时应用免疫荧光、蛋白质印迹、荧光素酶报告系统等研究发现,5-8F细胞可受到LPS的诱导而活化TLR4的下游信号传导通路.5-8F细胞在LPS的诱导下,磷酸化NFκBp65的表达增加,并且使NFκBp65活化迁移至核内.研究还发现,LPS增加TNF-α全长启动子活性,同时LPS可使5-8F细胞中TNF-α的分泌增加,从而介导炎性因子的释放.因此,5-8F细胞可通过与LPS受体分子:CD14、TLR4及MD2与LPS相结合并反应,从而激活TLR4介导的NFκB信号通路,使炎性因子的释放增加,导致鼻咽部的炎症反应诱发鼻咽癌.     

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。     

肠道菌群变化对肠上皮细胞Myd88蛋白及炎症因子的影响

目的 研究肠道菌群变化对体外培养的正常大鼠肠黏膜上皮细胞Myd88蛋白水平及其下游TNF-α等炎症因子的影响。方法 选取10只健康大鼠,实验室适应性喂养5 d后继续常规喂养7 d并处死,取结肠组织进行细胞培养得到原代肠黏膜上皮细胞,将所得细胞分为5组,分别用正常细胞培养液（A组）、正常大鼠肠腔菌溶液（B组）、正常大鼠黏膜菌溶液（C组）、溃疡性结肠炎大鼠肠腔菌溶液（D组）、溃疡性结肠炎大鼠黏膜菌溶液（E组）培养,通过蛋白质印迹法检测各组细胞中Myd88蛋白含量,通过酶联免疫吸附法检测TNF-α和IL-6含量。结果 D组、E组与A组比较,细胞中Myd88蛋白及TNF-α、IL-6水平显著增高（Ps＜0.01）,D、E组与B、C组比较Myd88蛋白及TNF-α、IL-6水平亦显著增高（Ps＜0.01）,而B组、C组相较于A组差异无统计学意义（Ps＞0.05）。进一步比较D组与E组、B组与C组间Myd88蛋白及TNF-α、IL-6水平差异亦无统计学意义（Ps＞0.0.5）。结论 （1）肠道菌群结构的改变可引起肠黏膜细胞Myd88通路的激活及炎症因子的释放。（2）肠道中细菌种类、数量、分布位置等因素的综合变化与肠黏膜炎症反应的发生关系密切。     

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.     

Regulation of MyD88 Aggregation and the MyD88-dependent Signaling Pathway by Sequestosome 1 and Histone Deacetylase 6

MyD88 is an essential adaptor molecule for Toll-like receptors (TLRs) and interleukin (IL)-1 receptor. MyD88 is thought to be present as condensed forms or aggregated structures in the cytoplasm, although the reason has not yet been clear. Here, we show that endogenous MyD88 is present as small speckle-like condensed structures, formation of which depends on MyD88 dimerization. In addition, formation of large aggregated structures is related to cytoplasmic accumulation of sequestosome 1 (SQSTM1; also known as p62) and histone deacetylase 6 (HDAC6), which are involved in accumulation of polyubiquitinated proteins. A gene knockdown study revealed that SQSTM1 and HDAC6 were required for MyD88 aggregation and exhibited a suppressive effect on TLR ligand-induced expression of IL-6 and NOS2 in RAW264.7 cells. SQSTM1 and HDAC6 were partially involved in suppression of several TLR4-mediated signaling events, including activation of p38 and JNK, but they hardly affected degradation of IκBα (inhibitor of nuclear factor κB). Biochemical induction of MyD88 oligomerization induced recruitment of SQSTM1 and HDAC6 to the MyD88-TRAF6 signaling complex. Repression of SQSTM1 and HDAC6 enhanced formation of the MyD88-TRAF6 complex and conversely decreased interaction of the ubiquitin-specific negative regulator CYLD with the complex. Furthermore, ubiquitin-binding regions on SQSTM1 and HDAC6 were essential for MyD88 aggregation but were not required for interaction with the MyD88 complex. Thus, our study reveals not only that SQSTM1 and HDAC6 are important determinants of aggregated localization of MyD88 but also that MyD88 activates a machinery of polyubiquitinated protein accumulation that has a modulatory effect on MyD88-dependent signal transduction.     

胎儿稽留流产与染色体异常的关系及其影响因素分析

目的：探讨B超联合FISH实验室诊断技术分析胎儿稽留流产与染色体非整倍体关系并对其他影响因素进行综合分析。方法：采用FISH技术对广西267例B超诊断为稽留流产孕妇的胎儿绒毛组织行13,16,18,21,22,X,Y染色体数目检测,荧光显微镜下观察结果;采用SPSS13．0对相关数据进行统计分析。结果：267例稽留流产胎儿绒毛组织中,染色体数目异常95例,异常率35．6％,数目异常以三体最常见,其次为四体,少见部分单体;异常病例样本中存在多种染色体混合嵌合体现象,如混合嵌合三体（2n＋1／2n）,混合嵌合四体（2n＋2／2n）,混合嵌合单倍体、三体、四体（2n-1／2n＋l／2n＋2／2n）等;稽留流产与患者年龄、流产史、孕周具有显著相关性。结论：染色体数目异常与染色体混合嵌合均是稽留流产的重要原因,同时稽留流产发生与患者高龄、多次流产史、早期妊娠密切关系。     

自然流产患者绒毛和蜕膜中ZEB1 的差异性表达及意义*

摘要目的：检测锌指结合蛋白（zinc finger E-box-binding protein ,ZEB1）在自然流产患者绒毛和蜕膜组织中的差异性表达。方法： 选取2010 年3 月到2011 年3 月在我院妇产科门诊进行人工流产的患者,分为正常人工流产（对照组50 例）和自然流产（实验组 50 例）两组,两组年龄和孕周间差异无统计学意义（P＞0.05）。用荧光实时定量PCR（qRT-PCR）技术检测在绒毛和蜕膜组织中 ZEB1 mRNA的表达量。结果：自然流产患者绒毛（0.835± 0.047）中ZEB1的表达量低于对照组（1.942± 0.095）,自然流产患者蜕 膜（0.65± 0.058）中ZEB1 的表达量低于对照组（1.13± 0.084）,差异具有统计学意义(P＜0.05)。结论：绒毛及蜕膜组织中ZEB1 的 异常表达可能参与自然流产的发生发展过程。     

TLR2 synergizes with both TLR4 and TLR9 for induction of the MyD88-dependent splenic cytokine and chemokine response to Streptococcus pneumoniae

We previously demonstrated that induction of splenic cytokine and chemokine secretion in response to Streptococcus pneumoniae (Pn) is MyD88-, but not critically TLR2-dependent, suggesting a role for additional TLRs. In this study, we investigated the role of TLR2, TLR4, and/or TLR9 in mediating this response. We show that a single deficiency in TLR2, TLR4, or TLR9 has only modest, selective effects on cytokine and chemokine secretion, whereas substantial defects were observed in TLR2(-/-)xTLR9(-/-) and TLR2(-/-)xTLR4(-/-) mice, though not as severe as in MyD88(-/-) mice. Chloroquine, which inhibits the function of intracellular TLRs, including TLR9, completely abrogated detectable cytokine and chemokine release in spleen cells from TLR2(-/-)xTLR4(-/-) mice, similar to what is observed for mice deficient in MyD88. These data demonstrate significant synergy between TLR2 and both TLR4 and TLR9 for induction of the MyD88-dependent splenic cytokine and chemokine response to Pn.     

Toll-like receptors and fungal infections: the role of TLR2, TLR4 and MyD88 in paracoccidioidomycosis

The aim of this minireview is to present a concise view of the most important pattern recognition receptors used by the innate immune system to sense and control pathogen growth into host tissues. A brief review of the role of Toll-like receptors (TLRs) in fungal infections followed by some recent results on the function of TLR4, TLR2 and the MyD88 adaptor molecule in the pathogenesis of paracoccidioidomycosis are presented.