gp130-linked signal transduction promotes the differentiation and maturation of dendritic cells

In order to explore the role of gp130-linked signal transduction in the differentiation and maturation of dendritic cells (DC), the mAb, B-S12, an agonist of gp130, was used for the activation of gp130 on DC. The effects of cytokines and of anti-gp130 mAb on the proliferation of DC, and their expression of IL-12 and CD80 (B7-1) by DC were evaluated. DC differentiating from peripheral blood mononuclear cells did not express the IL-6 receptor alpha chain, but expressed gp130. Anti-gp130 mAb promoted the proliferation of DC, induced by IL-4 and granulocyte macrophage colony stimulating factor (GM-CSF), by up-regulating the GM-CSF receptor on DC. DC induced by gp130 mAb and cytokines expressed DC-derived CC chemokine, as measured by RT-PCR. Induced DC also stimulated strong proliferation of autologous T cells in mixed lymphocyte reaction since an up-regulated expression of IL-12 and CD80 (B7-1) was observed in DC activated by anti-gp130 mAb. Thus, gp130 signal transduction is important for the differentiation and maturation of DC.     

Integrin signal transduction in myeloid leukocytes

Integrin-mediated adhesion serves as a powerful costimulus for neutrophil activation. Clustering of integrins at the leukocyte membrane by interaction with surface-bound ligands (extracellular matrix proteins or endothelial cell counter-receptors) leads to a number of signaling events that culminate in actin cytoskeletal rearrangement and neutrophil functional responses such as migration, degranulation, and respiratory burst. Although the signaling reactions elicited by integrin ligation are complex and the relative contribution of each pathway to neutrophil function is unclear, a large body of evidence suggests that activation of tyrosine kinases is a very proximal event in these signaling cascades. This review summarizes the role of adhesion in activating neutrophil functional properties and the contribution of leukocyte tyrosine kinases to regulation of integrin signaling in myeloid cells. Significant advances in our understanding of leukocyte integrin signaling have been afforded by studies using knockout mice lacking members of the Src-family of tyrosine kinases normally expressed in myeloid cells. These studies have demonstrated that these kinases (Hck, Fgr, and Lyn) are not required for myeloid cell development or for many of the functional properties of myeloid cells but are critical in controlling integrin-mediated signaling events. Absence of these kinases results in impaired adhesion-dependent neutrophil activation both in vivo and in vitro. These studies suggest that leukocyte-specific tyrosine kinases may be good therapeutic targets for controlling myeloid cell-dependent inflammatory disease.     

尼古丁对哮喘大鼠树突状细胞髓样分化因子88及白介素-10、白介素-12表达的影响

目的通过研究尼古丁对哮喘大鼠模型树突状细胞(DCs)Toll受体转导途径中重要接头蛋白髓样分化因子88(MyD88)表达影响及其与白介素-10(IL-10)、白介素-12(IL-12)的关系,从细胞水平探讨尼古丁加重哮喘的免疫学机制。方法制备哮喘大鼠模型,培养骨髓来源的DCs及脾脏来源的淋巴细胞,实验随机分为4组:对照组、哮喘组、尼古丁组和哮喘加尼古丁组,其中对照组和哮喘组大鼠DCs在培养5 d后在培养液中加入一定体积的PBS继续培养72 h,尼古丁组和哮喘加尼古丁组大鼠DCs在培养5 d后加入质量浓度为400μg/ml尼古丁作用72 h。收集各组细胞及细胞上清,采用酶联免疫吸附双抗体夹心法(ELISA)测定各组IL-10和IL-12的浓度。采用免疫印迹(Western blot)法测定细胞内MyD88的含量。采用MTT法测定DCs刺激同种异体淋巴细胞增殖的能力。结果①哮喘加尼古丁组和哮喘组大鼠DCs IL-10的表达均高于对照组,IL-12的表达均低于对照组,差异均具有统计学意义(P<0.01)。哮喘加尼古丁组大鼠DCs IL-10和IL-12的表达均低于哮喘组大鼠,差异均具有统计学意义(P<0.05)。②尼古丁组、哮喘组和哮喘加尼古丁组大鼠DCs MyD88的表达低于对照组,差异均具有统计学意义(P<0.05)。哮喘加尼古丁组大鼠DCs MyD88的表达低于哮喘组,差异均具有统计学意义(P<0.01)。③哮喘组大鼠DCs刺激同种异体淋巴细胞增殖的能力与对照组相比明显增强,差异具有统计学意义(P<0.01)。哮喘加尼古丁组大鼠DCs刺激同种异体淋巴细胞增殖的能力与哮喘组和对照组相比明显减弱,差异均具有统计学意义(P<0.05)。④DCs MyD88的表达与IL-12呈显著的正相关(r=0.644,P<0.01),与IL-10的表达无明显相关性。IL-12与IL-10的表达呈显著的负相关(r=-0.388,P<0.05)。DCs中IL-10的表达与淋巴细胞增殖活性呈显著的正相关(r=0.524,P<0.01);IL-12的表达与淋巴细胞增殖活性无明显相关性。结论尼古丁可以抑制哮喘大鼠DCs MyD88以及IL-10、IL-12的表达,并降低DCs刺激淋巴细胞的增殖能力。这可能是吸烟加重哮喘的免疫学机制之一。其中MyD88依赖的Toll受体转导途径可能在尼古丁下调IL-12的表达中发挥了一定作用。     

Stimulatory and inhibitory differentiation of human myeloid dendritic cells

Dendritic cells (DCs) play a critical obligate role in presenting antigens to T cells for activation. In the process, upon antigen capture, DCs undergo maturation and become more stimulatory. Human myeloid DCs can be generated from various sources, including blood, bone marrow, and CD34(+) stem cells. As such, plastic-adherent monocytes from circulation have served as a ready source for generating myeloid DCs in culture in granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) for translational research in active specific immunotherapy, especially in cancer, with the belief that they are essentially stimulatory or "immunogenic." Here we show that in vitro cultures of plastic-adherent circulating monocytes in GM-CSF and IL-4 followed by further maturation in interferon-gamma plus bacterial superantigens (DC maturing agents) can give rise to two diametrically opposite types of DCs-one stimulatory and another inhibitory. The stimulatory DCs express higher amounts of costimulatory molecules, synthesize IL-12, and efficiently stimulate naive allogeneic T cells in mixed lymphocyte reaction (MLR). The inhibitory DCs, in contrast, express lower concentrations of the critical costimulatory molecules, synthesize large amounts of IL-10, and are nonstimulatory in allogeneic primary MLR. Moreover, while the stimulatory DCs further amplify proliferation of T cells in lectin-driven proliferation assays, the inhibitory DCs totally block T cell proliferation in similar assays, in vitro. Most interestingly, neutralization of the endogenously derived IL-10 with anti-IL-10 antibody in DC cultures repolarizes the inhibitory DCs toward stimulatory phenotype. Accordingly, these observations have important implications in translational research involving myeloid DCs.     

HSP60及TLR4信号途径在小鼠心脏移植物中的表达及意义

目的:检测HSP60及TLR4信号途径在小鼠心脏移植物中的表达情况,探讨其在心脏移植排斥反应中的作用以及它们之间的关系。方法:建立小鼠颈部心脏移植模型,随机分为2组:对照组(同系移植组),供、受体均为C57BL/6小鼠;实验组(同种异品系移植组),供、受体分别为BALB/c、C57BL/6小鼠。分别于移植后第3d、第7d取小鼠心脏及血液标本,免疫组化及Western blotting检测心脏移植物HSP60、TLR4、MyD88及NF-κB的表达情况,ELISA法检测小鼠血液肿瘤坏死因子-α(TNF-α)、干扰素-γ(IFN-γ)和白细胞介素-12(IL-12)的浓度,病检分析心脏组织形态学改变。结果:实验组心脏移植物HSP60、TLR4、MyD88、NF-κB的表达及TNF-α、IFN-γ、IL-12的浓度明显高于对照组;病理学检查结果显示实验组小鼠在术后第3、7d分别发生轻、重度排斥,对照组无明显排斥现象。结论:心脏移植后HSP60表达增强,可能通过TLR4以MyD88依赖的方式激活TLR4信号途径,从而促进移植排斥反应的发生,调控HSP60及其受体后信号途径可能为抗排斥反应提供新思路。     

青藤碱对胶原诱导性关节炎小Toll样受体4/髓样分化因子88通路的影响

目的 探讨青藤碱(sinomenine,SN)对胶原诱导性关节炎(collagen-induced arthritis,CIA)小Toll样受体4(toll like receptor 4,TLR4)/髓样分化因子88(myeloid differentiation factor 88,MyD88)信号通路诱导炎症的影响.方法 6周龄DBA/1小30只,随机分为正常对照组、CIA组及SN组,每组10只.其中CIA组及SN组小鼠尾根部初次免疫及加强免疫Ⅱ型胶原乳剂诱导CIA模型.小鼠初次免疫d28开始灌胃给药,SN组予SN治疗,正常对照组和CIA组予生理盐水作为对照.连续治疗20 d后处死小鼠,观察药物对小鼠关节肿胀的影响,收集膝关节滑膜及血清.Western blot法检测滑膜TLR4及MyD88蛋白表达,酶联免疫吸附试验(enzyme-linked immunosorbent assays,ELISA)检测血清炎性因子肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)的水平.结果 经治疗后,SN组小鼠关节肿胀情况较CIA组改善明显,差异有统计学意义[d41(5.50±1.38)比(9.67±2.34),P<0.05;d48(1.67±0.52)比(3.33±1.21),均P<0.05];TLR4、MyD88蛋白表达及血清炎性因子TNF-α均较CIA组下降,差异有统计学意义[TLR4/β-actin:(0.33±0.05)]比(0.62±0.05)];MyD88/β-actin:(0.10±0.02)比(0.33±0.03);TNF-α:(169.16±10.68)比(347.97±13.45),均P<0.05].结论 SN可改善CIA小鼠的关节炎症,该作用可能与其抑制TLR4/MyD88信号通路有关.     

Amyloid beta peptide promotes differentiation of pro-inflammatory human myeloid dendritic cells

A key event of Alzheimer's disease (AD) pathogenesis is the production of amyloid beta peptides (A beta), which are hypothesized to lead to neurodegeneration by still unclear mechanisms, including a chronic inflammatory response characterized by innate immune cell activation and pro-inflammatory molecule release. Since dendritic cells (DCs) are central players of innate immune response and brain dendritic-like cells may have a crucial role in AD pathogenesis, this study investigates the effects of A beta on human DC functions. Myeloid DCs differentiated in the presence of A beta 42 showed an increase in survival and soluble antigen uptake, a reduction in HLA molecule expression and in IL-10 and IL-12 production. Accordingly, A beta 42-treated DCs were impaired in inducing T cell proliferation and IL-2 production. On the other hand, A beta 42 treatment provided DCs with the ability to release higher levels of IL-1 beta, IL-6 and IL-18, than control DCs. These results demonstrate that A beta 42 can modulate the immune system by inducing pro-inflammatory DC differentiation, thus gaining new insights into AD pathogenesis and immune-based therapeutic intervention.     

Molecular cloning and functional characterization of a novel isoform of chicken myeloid differentiation factor 88 (MyD88)

Myeloid differentiation factor 88 (MyD88) is an adaptor protein involved in the interleukin-1 receptor- and Toll-like receptor-induced activation of nuclear factor-kappaB (NF-kappaB). A novel isoform of chicken MyD88, designated chicken MyD88-2, has been cloned and functionally characterized. Its open reading frame is of length 900bp, and it encodes a predicted 299 residue protein, similar in length to its mammalian orthologues, but, respectively, 77 and 69 amino acids shorter than the previously described chicken MyD88-1 and -3. The amino acid sequence of chicken MyD88-2 displays 96.9%, 96.9%, 70.4% and 70.2% identity with, respectively, chicken MyD88-1, -3, human and mouse MyD88. Chicken MyD88-2 expression was detected in a range of tissues tested, but no expression of either chicken MyD88-1 or -3 was observed. The over-expression of chicken MyD88-2 significantly induced the activation of NF-kappaB in vitro, suggesting that chicken MyD88-2 plays an important role in the innate immune responses of chicken.     

Lethal encephalitis in myeloid differentiation factor 88-deficient mice infected with herpes simplex virus 1

Herpes simplex virus 1 (HSV-1), a large DNA virus from the Herpesviridae family, is the major cause of sporadic lethal encephalitis and blindness in humans. Recent studies have shown the importance of Toll-like receptors (TLRs) in the immune response to HSV-1 infection. Myeloid differentiation factor 88 (MyD88) is a critical adaptor protein that is downstream to mediated TLR activation and is essential for the production of inflammatory cytokines. Here, we studied the relationship between MyD88 and HSV-1 using a purified HSV-1 isolated from a natural oral recurrent human infection. We observed the activation of TLR-2 by HSV-1 in vitro using Chinese hamster ovary cells stably transfected with a reporter gene. Interestingly, we found that only peritoneal macrophages from MyD88-/- mice, but not macrophages from TRL2-/- or from wild-type mice, were unable to produce tumor necrosis factor-alpha in response to HSV-1 exposure. Additionally, although TLR2-/- mice showed no enhanced susceptibility to intranasal infection with HSV-1, MyD88-/- mice were highly susceptible to infection and displayed viral migration to the brain, severe neuropathological signs of encephalitis, and 100% mortality by day 10 after infection. Together, our results suggest that innate resistance to HSV-1 is mediated by MyD88 and may rely on activation of multiple TLRs.     

斑马鱼类胰岛素生长因子信号途径及作用机制研究进展

斑马鱼是研究早期发育中类胰岛素生长因子（insulin-like growth factors, IGF）信号途径的模式生物,斑马鱼IGF信号系统主要包括IGF配体、受体、结合蛋白（IGFBPs）。IGF配体包括IGF-1,IGF-2。受体为IGF-1R,该受体有两种全长结构（igf-1ra和igf-1rb）。结合蛋白包括IGFBP-1,IGFBP-2,IGFBP-3,IGFBP-5和 IGFBP-6,它们的结构特征已经阐明,从斑马鱼模式动物中获得的信息不仅可以为斑马鱼胚胎发育生物学提供新的观点,还可以进一步加深我们对一般意义上的脊椎动物的生长和发育的理解。本文就近年来斑马鱼IGF系统的进展作一综述。     

Role for moesin in lipopolysaccharide-stimulated signal transduction

Moesin is a 78-kDa protein with diverse functions in linking the cytoskeleton to the membrane while controlling cell shape, adhesion, locomotion, and signaling. The aim of this study was to characterize the expression and localization of moesin in mononuclear phagocytes by using confocal microscopy, flow cytometry, immunoprecipitation, and Western blotting and to analyze the function of moesin as a lipopolysaccharide receptor, utilizing an antisense oligonucleotide approach to knock down the moesin gene. Results revealed that moesin is expressed on the surface of monocytes/macrophages and surface expression is increased after lipopolysaccharide stimulation. The total protein mass of moesin is increased in monocytes after lipopolysaccharide stimulation. Immunoprecipitation showed that moesin coprecipitates with TLR4, a well-known lipopolysaccharide receptor, suggesting an early role of moesin in the formation of the initiation complex for lipopolysaccharide signaling. Two antisense and two control sense oligonucleotides were synthesized and introduced every 4 h for 48 h in adherent macrophage-like cells. Cells were then stimulated with lipopolysaccharide for 4 h, and the supernatants were assayed for tumor necrosis factor alpha (TNF-alpha) production. Cell lysates were assayed for moesin expression by Western blotting immediately after the 48-h treatment period and also after 116 h of recovery to assess the return of moesin expression and function. Moesin gene expression was completely suppressed after 48 h of incubation with antisense oligonucleotides. The antisense elimination of moesin gene expression led to a significant reduction of lipopolysaccharide-induced TNF-alpha secretion. Restoration of moesin gene expression led to restoration of TNF-alpha production. These data suggest an important role for moesin in lipopolysaccharide-induced TNF-alpha production, highlighting its importance in lipopolysaccharide-mediated signal transduction.     

Staphylococcus aureus-induced corneal inflammation is dependent on Toll-like receptor 2 and myeloid differentiation factor 88

Toll-like receptors (TLRs) expressed by the corneal epithelium represent a first line of host defense to microbial keratitis. The current study examined the role of TLR2, TLR4, and TLR9 and the common adaptor molecule myeloid differentiation factor 88 (MyD88) in a Staphylococcus aureus model of corneal inflammation. The corneal epithelia of C57BL/6, TLR2(-/-), TLR4(-/-), TLR9(-/-), and MyD88(-/-) mice were abraded using a trephine and epithelial brush and were exposed to heat- or UV-inactivated S. aureus clinical strain 8325-4 and other clinical isolates. Corneal thickness and haze were measured by in vivo confocal microscopy, neutrophil recruitment to the corneal stroma was quantified by immunohistochemistry, and cytokine production was measured by enzyme-linked immunosorbent assay. The exposure of corneal epithelium to S. aureus induced neutrophil recruitment to the corneal stroma and increased corneal thickness and haze in control C57BL/6 mice but not in TLR2(-/-) or MyD88(-/-) mice. The responses of TLR4(-/-) and TLR9(-/-) mice were similar to those of C57BL/6 mice. S. aureus-induced cytokine production by corneal epithelial cells and neutrophils was also significantly reduced in TLR2(-/-) mice compared with that in C57BL/6 mice. These findings indicate that S. aureus-induced corneal inflammation is mediated by TLR2 and MyD88 in resident epithelial cells and infiltrating neutrophils.     

钙离子载体诱导HL-60细胞分化成树突状细胞的实验研究

目的 :探讨一种钙离子载体 (calciumionophore,CI)A2 3187,能否诱导早幼粒白血病细胞株HL 6 0分化成具有活性的树突状细胞 (dendriticcells,DCs)。方法 :将生长状态良好的HL 6 0细胞分别加在普通培养液中 ,或在含不同浓度 (2 5～ 16 0 0 μg/L)的A2 3187及 10 0 μg/L重组人粒 /单集落刺激因子 (rhGM CSF)的普通培养液中培养。 2 4～ 96h后 ,在光镜及电镜下观察细胞的形态 ;用流式细胞仪检测细胞的表面标志 ,MTT比色法检测其刺激同种异体T细胞增殖的作用。结果 :HL 6 0细胞以适量 (2 0 0 μg/L)的A2 3187诱导 2 4h ,DC的特征性表面标志CD83分子的表达最高 ,72h可出现典型的树突状突起 ,96h细胞表面CD80 (B7.1)、CD86 (B7.2 )、MHC II分子及细胞间黏附分子CD5 4的表达最高 ,且能明显激活同种异体T细胞。结论 :钙离子载体A2 3187可将HL 6 0细胞诱导成具有活性的DC样细胞。     

Identification and characterization of a myeloid differentiation factor 88 (MyD88) cDNA and gene in Japanese flounder, Paralichthys olivaceus

The interleukin-1 receptor/toll-like receptor (IL-1R/TLR) superfamily signaling involves myeloid differentiation factor 88 (MyD88) that acts as an important adapter protein. A Japanese flounder (Paralichthys olivaceus) MyD88 (jfMyD88) cDNA and gene were cloned, and found to have lengths of 1.5 and 3.01 kb, respectively. The ORF encodes 285 amino acids that contain a death domain and a Toll/IL-1 receptor domain. The gene is composed of 5 exons and 4 introns. The jfMyD88 gene is highly expressed in organs involved in immune functions, including the gills, intestines, kidney, skin and spleen. Three days after a fish was infected with Edwardsiella tarda, staining with anti-jfMyD88 polyclonal antibody revealed an increased population of MyD88-positive cells in the kidney and spleen. These results imply that MyD88 has an important role in the innate immune system in Japanese flounder.     

RNA干扰抑制MyD88表达对小鼠骨髓树突状细胞生物学活性的影响

目的:采用RNA干扰技术抑制小鼠骨髓树突状细胞(DC)髓样分化因子88(MyD88)的表达,并检测其对细胞生物学活性的影响,为DC的临床应用奠定基础。方法:针对MyD88基因,采用化学合成法合成3对MyD88 siRNA(序列1、序列2及序列3),并转染DC2.4细胞。采用半定量RT-PCR及Western blot分别从mRNA和蛋白质水平检测DCMyD88的表达情况,筛选其中一对高效RNA(序列3)转染DC2.4细胞(RNA干扰组),以未转染RNA的DC2.4细胞作为对照组,分别给予1 mg/L的脂多糖(LPS)刺激。流式细胞术(FCM)检测DC细胞表面CD80、CD86及MHC-Ⅱ分子的变化,ELISA法检测DC分泌肿瘤坏死因子-α(TNF-α)、干扰素-γ(IFN-γ)和白介素-12(IL-12)的浓度,免疫细胞化学检测DC核因子-κB(NF-κB)的表达,混合淋巴细胞培养检测T细胞增殖能力,观察RNA干扰对LPS促DC成熟的影响。结果:与空白对照组相比,序列2组及序列3组DC的mRNA和蛋白质表达分别降低90%和85%、92%和88%,差异有统计学意义;脂质体对照组、无义siRNA对照组及序列1组DC的mRNA和蛋白质表达无显著差异。经LPS刺激后,与对照组相比,RNA干扰组CD80、CD86及MHC-Ⅱ分子的表达,TNF-α、IFN-γ及IL-12的浓度及T细胞增殖能力均显著下降,且未见明显NF-κB核转位。结论:RNA干扰技术能显著下调小鼠DC MyD88的表达,并显著抑制LPS促DC成熟的效应,为以DC MyD88为靶向、相关疾病的基因治疗提供了新思路和手段。     

Cooperation in signal transduction of extracellular guanosine 5' triphosphate and nerve growth factor in neuronal differentiation of PC12 cells

Guanosine 5' triphosphate (GTP), acting synergistically with the nerve growth factor (NGF), enhances the proportion of neurite-bearing cells in cultures of PC12 rat pheochromocytoma cells. We studied the transduction mechanisms activated by GTP in PC12 cells and found that addition of GTP (100 microM) increased intracellular calcium concentration ([Ca(2+)](i)) in cells that were between 60 and 70% confluent. Addition of GTP also enhanced activation of NGF-induced extracellular regulated kinases (ERKs) and induced Ca(2+) mobilization. This mobilization, due to the activation of voltage-sensitive and ryanodine-sensitive calcium channels, as well as pertussis toxin-sensitive purinoceptors, modulates Ca(2+)-activated K(+) channels not involved in activation of ERKs. The results presented here indicate that GTP-triggered [Ca(2+)](i) increase may be a key event in GTP signal transduction, which can modulate activity of ERKs. The physiological importance of the GTP effect lies in its capacity to interact with the NGF-activated pathway to enhance neurite outgrowth from PC12 cells.     

成骨细胞分化与信号转导研究进展

成骨细胞在骨的生长、发育及形成过程中起重要作用,其分化受严格调控,通过多种信号途径实现对成骨细胞的定向分化。综述了G蛋白信号调节因子、BMP/Smads、MAPK、PI3-k以及细胞因子等信号通路在成骨细胞定向分化方面的研究进展。     

Transforming growth factor beta signal transduction

Transforming growth factor beta1 (TGF-beta1) is the prototypic member of a large family of structurally related pleiotropic-secreted cytokines that play a pivotal role in the control of differentiation, proliferation, and state of activation of many different cell types including immune cells. TGF-beta family members have potent immunosuppressor activities in vitro and in vivo. These cytokines trigger their biological effects by inducing the formation of a heteromeric transmembrane serine/threonine kinase receptor complex. These receptors then initiate intracellular signaling through activation of Smad proteins, and specific Smads become phosphorylated and associate with other Smads. These heteromeric Smad complexes accumulate in the nucleus, where they modulate the expression of target genes. Recent data support the notion that Smads are important intracellular effectors of TGF-beta in immune cells. Here, we review recent advances in TGF-beta signal transduction in immune cells.     

成骨细胞分化与信号转导研究进展

成骨细胞在骨的生长、发育及形成过程中起重要作用，其分化受严格调控，通过多种信号途径实现对成骨细胞的定向分化。综述了G蛋白信号调节因子、BMP／Smads、MAPK、PI3-k以及细胞因子等信号通路在成骨细胞定向分化方面的研究进展。