豨莶草醇提物调控TLRs/NF-κB通路及NLRP3炎症小体干预痛风性关节炎的机制研究

目的探讨豨莶草醇提物通过Toll样受体(TLRs)/核因子κB(NF-κB)信号通路及NOD样受体蛋白3(NLRP3)干预痛风性关节炎(GA)的作用机制。方法采用脂多糖(LPS)联合尿酸钠结晶(MSU)刺激急性单核细胞白血病细胞(THP-1)源性巨噬细胞,建立GA炎症细胞模型;以豨莶草醇提物300、200、100μg·mL^-1不同浓度进行干预。采用CCK-8法检测细胞活力;ELISA法检测细胞上清中白细胞介素-1β(IL-1β)的水平;qRT-PCR法检测TLRs/NF-κB信号通路相关基因(TLR2、TLR4、MYD88、IRAK-1、TRAF-6、TAK-1、NF-κB、IL-1β)及NLRP3 m RNA的表达;Western Blot法检测NF-κB、NLRP3、IL-1β蛋白的表达。结果与对照组比较,豨莶草醇提物300、200、100μg·mL^-1浓度对THP-1巨噬细胞活力均无明显影响(P>0.05);模型组的IL-1β水平明显升高(P<0.05),TLRs/NF-κB信号通路相关基因及NLRP3 mRNA表达水平均明显上调(P<0.05),NF-κB、NLRP3、IL-1β蛋白表达水平明显上调(P<0.05)。与模型组比较,豨莶草醇提物300、200、100μg·mL^-1浓度组的细胞IL-1β水平明显降低(P<0.05),TLRs/NF-κB信号通路相关基因及NLRP3 mRNA表达水平均不同程度下调(P<0.05),NF-κB、NLRP3及IL-1β蛋白表达水平亦不同程度下调(P<0.05)。结论豨莶草醇提物可能通过调控TLRs/NF-κB信号通路及抑制NLRP3炎症小体活化,减少炎症因子的产生与释放,进而减轻痛风性炎症反应。     

An intrinsic B-cell defect supports autoimmunity in New Zealand black chromosome 13 congenic mice

Introgression of a New Zealand Black (NZB) chromosome 13 interval onto a C57BL/6 (B6) background (B6.NZBc13) is sufficient to produce many hallmarks of lupus, including high-titre anti-chromatin antibody production, abnormal B- and T-cell activation, and renal disease. In this study we sought to characterize the immune defects leading to these abnormalities. By generating hematopoietic chimeras and BCR transgenic mice, we show that the congenic autoimmune phenotype can be transferred by BM cells and requires the presence of autoreactive B cells. Using the hen egg white lysozyme immunoglobulin transgenic mouse model, we demonstrate that B-cell anergy, deletion, and receptor editing are intact. Nevertheless, congenic B cells exhibit altered peripheral B-cell selection, as demonstrated by enhanced survival and activation of endogenous B cells with autoreactivity to chromatin and Sm/ribonucleoprotein. Given the autoantibody specificities to nuclear antigens, TLR signalling was assessed. B6.NZBc13 B cells were hyper-responsive to poly(I:C), a TLR3 ligand, demonstrating enhanced proliferation and survival as compared to B6 B cells. Our findings indicate the presence of an intrinsic B-cell defect on NZB chromosome 13 that results in hyper-responsiveness to a dsRNA analogue and implicates its potential supporting role in the generation of autoimmunity in B6.NZBc13 mice.     

The expanding roles of ITAM adapters FcRγ and DAP12 in myeloid cells

Summary:  The adapter proteins DAP12 and FcRγ associate with a wide spectrum of receptors in a variety of innate immune cells to mediate intracellular signaling pathways when their cognate receptor is engaged. These adapter proteins are coupled to their receptors through charged residues within the transmembrane regions of the adapter and receptor. DAP12 and FcRγ contain specific protein domains (referred to as immunoreceptor tyrosine-based activation motifs) that serve as the substrates and docking sites for kinases, allowing amplification of intracellular signaling reactions. Recent research has broadened the repertoire of receptors that utilize these adapters for signaling to include not only novel immunoglobulin superfamily members but also cytokine receptors, integrins, and other adhesion molecules. There is abundant evidence that these multifunctional signaling adapters also mediate inhibitory activity, downmodulating signaling from Toll-like receptors and other heterologous receptors. In this review, we discuss the newly described receptors that utilize DAP12 and/or FcRγ adapters to modulate innate immune responses.     

Toll样受体2和7在关节置换术后感染小鼠外周血白细胞中的表达

目的探讨Toll样受体(TLRs)2、7及其介导的天然免疫在关节置换术后感染中的作用。方法构建昆明小鼠的简易右膝关节置换术后表皮葡萄球菌感染模型。将动物实验分为假体置换术后感染组(A组)、假体置换术后无感染组(B组)、关节内注射细菌组(C组)和关节内注射生理盐水的对照组(D组)。于操作后的第1、3、7天眼球取血0.2ml,流式细胞术分析TLR2和TLR7在外周血白细胞的表达;取血后处死并取右膝关节及周围组织作细菌培养。对各组各时相TLR2和TLR7的表达水平结果进行统计分析,组间同一指标比较采用重复测量方差分析,同组内同一指标术前术后变化水平比较采用自身配对t检验。结果 A组、C组的组织培养均为阳性,B组、D组的组织培养均为阴性。操作后第1天,A/B组对比,TLR2(t=-31.562,P0.001)、TLR7(t=-27.213,P0.05)的比较均有统计学意义。第3天,A/B组间的TLR2的对比仍有统计学意义,至第7天,TLR2的表达在各组间的比较均无统计学意义。在感染情况下,有假体的A组和无假体的C组对比,TLR7有统计学意义(P0.001),而TLR2无统计学意义(P0.05)。结论 TLR2在人工关节置换术后假体感染中具有一定的作用,TLR7的表达可能受假体置入的影响。     

乙型肝炎e抗原、s抗原对Toll样受体及共刺激分子表达的调控和影响

目的：探讨乙型肝炎e抗原、s抗原（HBeAg、HBsAg）对健康人外周血单个核细胞（PBMC）Toll样受体（TLRs）和共刺激分子表达的影响。方法：分别用HBeAg、HBsAg、空质粒以及卵清蛋白（OVA）作为无关蛋白刺激健康人外周血单个核细胞（PBMC）,采用流式细胞技术检测各刺激组CD14＋细胞TLR2、TLR4、CD86、PD-L1的表达水平。结果：健康人PBMC经HBeAg或HBsAg刺激后,CD14＋细胞表面TLR2、TLR4的表达明显低于未刺激组（P〈0.05）,CD14＋细胞PD-L1的表达则明显增高（P〈0.05）;HBeAg刺激后同时可见CD14＋细胞表面共刺激分子CD86的表达水平明显降低（P〈0.02）。结论 HBeAg和HBsAg通过上调单核细胞表面PD-L1的表达,下调CD14＋单个核细胞表面TLR2、TLR4和共刺激分子CD86的表达,削弱机体固有免疫系统的应答能力,降低启动特异性免疫的活化信号,从而导致免疫清除逃避。因此,HBeAg和HBsAg可能是促进HBV感染慢性化的重要因素。     

Toll样受体在人乳头瘤病毒感染致宫颈癌中的作用

高危型人乳头瘤病毒(high-risk human papillomavirus,HR-HPV)持续感染是宫颈癌发生的明确病因,但并非所有HR-HPV感染都会导致宫颈癌,说明多种因素参与调节HR-HPV的致病性。Toll样受体(Toll-like receptors,TLRs)是一类模式识别受体,能特异性识别病原体相关...     

CpG-induced secretion of MHCIIβ and exosomes from salmon (Salmo salar) APCs

Major histocompatibility complex class II (MHCII) is encoded by polymorphic genes present in vertebrates and expressed predominately in leukocytes. Upon leukocyte differentiation, intracellular MHCII is dynamically redistributed within the cells and it is expressed at maximal levels on mature antigen presenting cells (APCs). In addition, APCs secrete MHCII within endosome-derived vesicles known as exosomes which possess diverse immunomodulatory properties. Genetic and biochemical data have confirmed that piscine leukocytes express the MHCII components as well as costimulatory molecules that are necessary for the function of APCs. However data concerning the biosynthesis and the distribution of the MHCII complex within leukocytes of lower vertebrates is scarce. The presented data demonstrates for the first time that salmon leukocytes secrete vesicles that contain exosomal markers and the abundance of MHCII indicates that these exosomes are released by APCs. The secretion was specifically induced by CpG stimulation in vitro and it was observed only in head kidney leukocytes but not in splenocyte cultures. Flow cytometry revealed that, unlike splenocytes, the majority of the MHCII-positive head kidney leukocytes were Ig-negative and a population of cells expressing high levels of surface MHCII underwent degranulation upon CpG stimulation suggesting that the MHCII-containing exosomes were derived from maturing salmon APCs. Gene expression analyses have further demonstrated that CpG-B, despite its relatively weak proinflammatory activity compared to LPS, induced expression of a larger group of genes involved in regulation of the adaptive immune response.