慢性乙肝患者ELR~- CXC趋化因子及其受体表达

趋化因子是一类结构功能相似、具有趋化吸引和活化作用的碱基肝素结合性的小分子蛋白质,依据其分子N端的Cys的排列顺序可分为CXC、CC、C和CX3C四个亚家族(C为半胱氨酸,X为任意氨基酸).根据CXC家族趋化因子结构功能区第一个半胱氨酸前是否有谷氨酸-亮氨酸-精氨酸(Glu-Leu-Arg)即ELR结构,将CXC趋化因子进一步分为ELR+CXC和ELR-CXC两个亚族.趋化因子受体是在中性粒细胞、巨噬细胞等炎症细胞和上皮细胞、成纤维细胞等结构细胞表面表达的具有七次跨膜域的受体,属G蛋白偶联受体(G protein-coupled receptors,GPCR)超家族成员,与ELR-CXC趋化因子结合的受体主要有CXCR3、CXCR4、CXCR5、CXCR7.     

CXC趋化因子与肿瘤血管新生

趋化因子在免疫调节、血管新生以及介导肿瘤的器官特异性转移中发挥重要作用。其中CXC趋化因子超家族由于N-端谷氨酸-亮氨酸-精氨酸基序(Glu-Leu-Arg,ELRmotif)的有无使其在血管新生过程中具有了促进或者抑制血管新生的不同作用:含有ELR(ELR )的CXC趋化因子经血管内皮组织上CXCR2介导血管新生促进作用;而不含有ELR(ELR-)的CXC趋化因子通过血管内皮组织上CXCR3介导血管新生抑制作用。     

IL-8-CXCR1/2信号通路与卵巢上皮癌关系的研究进展

<正>CXCR1/2是一类G蛋白偶联受体,CXCR1主要与IL-8结合,而CXCR2可以与多种配体(IL-1~3,Gro-α,β,γ,IL-8)结合,在机体内CXCR1与CXCR2具有协同的作用~([1])。CXCR1/2在正常机体内主要表达于中性粒细胞表面,当有外来病原体入侵,在组织局部引起炎症反应,炎症组织释放IL-8等趋化因子,经血液循环与中性粒细胞表面的CXCR1/2结合,从而趋化中性粒细胞迁移至炎症发生部位吞噬和杀灭病原体~([2])。此外,IL-8-CXCR1/2信号通路     

IL-8/CXCR1/2轴与膀胱癌关系的研究进展

白细胞介素8(IL-8)是一种具有趋化作用的小分子分泌型炎症性细胞因子,属于CXC趋化因子家族的成员,又名CXC趋化因子8(CXCL8).近年研究发现体内多种细胞如单核细胞、巨噬细胞、内皮细胞、角质形成细胞、肿瘤细胞等都具有分泌IL-8的能力.IL-8与其相应受体CXCRl/2结合后,除了对中性粒细胞有趋化和诱导其脱颗粒作用外,还可以通过促进血管形成、影响肿瘤细胞增殖、存活及运动,在肿瘤的发生、发展和转移中发挥重要作用.本文主要综述了IL-8及其受体与膀胱癌生物学行为的关系.     

烧伤患者中性粒细胞趋化因子变化分析

目的:探讨烧伤患者外周血中性粒细胞趋化因子的变化.方法:选取2018年2月至2020年5月我院救治的烧伤患者56例为研究组,选取60例健康志愿者为对照组,使用琼脂糖趋化实验来检测两组患者中性粒细胞的趋化距离,用酶联免疫吸附测定法来检测患者趋化因子受体阳性表达情况,然后对患者的中性粒细胞趋化距离及趋化因子受体阳性表达情况进行比较.结果:研究组患者的中性粒细胞的趋化距离均明显短于对照组(p<0.05);研究组患者入院3d时中性粒细胞趋化因子受体(CXC-chemokine receptor 1,CXCR1)与(CXC-chemokine receptor 1,CXCR2)受体阳性率均明显低于对照组(p<0.05),重度烧伤组患者的入院3d时中性粒细胞趋化因子受体CXCR1与CXCR2受体阳性率明显高于轻、中度烧伤组(p<0.05).研究组患者的IL-6、IL-10及TNF-α的水平明显高于对照组.结论:烧伤患者早期外周血中性粒细胞的趋化功能存在障碍,这可能与中性粒细胞趋化因子(CXCR1与CXCR2)的阳性表达率降低的有关.     

ELR+ CXC趋化因子诱导NETs生成的作用机制

目的探讨ELR~+ CXC趋化因子诱导中性粒细胞胞外诱捕网(neutrophil extracellular traps,NETs)生成的作用及机制。方法分离人外周血中性粒细胞,通过荧光染色和总MPO定量检测比较ELR~+ CXC趋化因子、ELR-CXC趋化因子和非趋化性细胞因子对NETs的诱导作用。以CXCL8为代表性ELR~+ CXC趋化因子,检测其诱导NETs的时效、量效关系,明确参与NETs生成的酶类成分,胞膜受体以及胞内信号分子机制。检测CXCL8对中性粒细胞ROS的上调效应及其在介导NETs生成中的作用。结果仅有ELR~+ CXC趋化因子可刺激NETs释放(P0.05或0.01)。其代表性因子CXCL8诱导NETs具有时间和剂量依赖性。抑制MPO、NE和PAD4活化,或者抑制CXCR1受体内化以及胞内ERK和p38的磷酸化,均可显著下调CXCL8诱导的NETs生成(P0.01)。CXCL8还通过上调NOX2并增加胞内ROS水平介导NETs生成。结论 ELR~+ CXC趋化因子可诱导NETs生成,该作用与其结合CXCR1,激活ERK和p38,诱导NOX2活化和上调ROS生成有关。     

CXCL16/CXCR6与炎症性疾病

多种临床疾病(包括肿瘤的发生)与炎症相关,因而趋化因子及其受体愈来愈受到广泛关注.近年有研究发现:人CXC型趋化因子配体16(CXC chemokine ligand 16,CXCL16)及其受体CXC型趋化因子受体6 (CXC chemokine receptor 6,CXCR6)在肾炎、肺部疾患、动脉粥样硬化、冠状动脉疾病、类风湿性关节炎等多种炎症性病变组织中表达;并且,在前列腺癌、结肠癌、乳腺癌等炎症相关肿瘤的肿瘤细胞或浸润性淋巴细胞上也有表达.CXCL16通过CXCR6介导免疫细胞向病变组织趋化,影响疾病转归,甚至参与肿瘤细胞增殖或血管生成.对CXCL16/CXCR6的深入研究,将为炎症性疾病的诊断和炎症相关肿瘤的预后提供参考.     

ITAC介导的T细胞跨血管内皮迁移及其后续事件

ITAC是ELR基序阴性的CXC亚家族趋化因子,ITAC通过趋化并活化表达CXCR3的细胞发挥免疫调节作用,并能介导T细胞跨血管内皮迁移,从而在局部组织浸润。ITAC与Thl型炎症疾病、自身免疫病、移植排斥及肿瘤的发生和发展相关。ITAC有望成为治疗这类疾病的靶分子。     

CXCL8及其受体CXCR1、CXCR2在慢性乙肝患者外周血PMNs中的表达

目的:探讨慢性乙肝患者外周血中性粒细胞(PMNs)上CXCL8及其受体CXCR1、CXCR2的表达。方法:以中性粒细胞分离液分离、纯化PMNs,检测患者血清HBe Ag及PMNs内HBV DNA,入选患者依据检测结果进行分组,SABC免疫细胞化学染色法检测各组患者PMNs内CXCL8及其受体CXCR1、CXCR2的表达。结果:SABC免疫细胞化学染色结果显示,CXCL8主要位于PMNs胞浆中,CXCR1、CXCR2多见于胞浆和胞膜上。其中HBe Ag(+)者CXCL8、CXCR1免疫着色较深,而CXCR2免疫着色较浅;PMNs内HBV DNA(+)者CXCL8、CXCR1免疫着色亦较深,而CXCR2免疫着色亦较浅。患者CXCL8和CXCR1的水平均显著升高,与正常对照相比,差异均有显著性(P0.05),而CXCR2的表达无统计学意义(P0.05)。结论:HBV侵染中性粒细胞后可促进CXCL8分泌,使胞膜CXCR1表达进一步增强。CXCL8、CXCR1、CXCR2免疫组化染色程度与患者HBe Ag表达、HBV DNA载量密切相关。高表达CXCR1的中性粒细胞与CXCL8相互作用,趋化吸引更多PMNs至病灶,参与局部炎性损伤和组织修复。     

IL-8,MCP-1,RANTES与妊娠的研究进展

趋化因子是一类对中性粒细胞、单核细胞、嗜酸性粒细胞等起激活和趋化作用的细胞因子,介导炎症与免疫反应。其中,白细胞介素-8属于趋化因子CXC亚族,单核细胞趋化蛋白-1和正常T细胞活化后所表达和分泌的调节蛋白属于趋化因子CC亚族,它们与妊娠关系密切,在胚胎植入、宫颈成熟、分娩发动中发挥重要作用,其表达异常可导致宫内感染、早产和流产。     

Evidence that cathelicidin peptide LL‐37 may act as a functional ligand for CXCR2 on human neutrophils

LL‐37, derived from human cathelicidin, stimulates immune responses in neutrophils. Although FPR2 and P2X7 were proposed as LL‐37 receptors, we have shown that among 21 neutrophil receptors only CXCR2 was down‐regulated by LL‐37. LL‐37 functions similarly to CXCR2‐specific chemokines CXCL1 and CXCL7 in terms of receptor down‐regulation and intracellular calcium mobilization on freshly isolated neutrophils. Neutrophils pretreated with CXCL8, a chemokine that binds both CXCR1/2, completely blocked the calcium mobilization in response to LL‐37, while LL‐37 also partially inhibited ¹²⁵I‐CXCL8 binding to neutrophils. SB225002, a selective CXCR2 antagonist, blocked LL‐37‐induced calcium mobilization and migration of neutrophils. LL‐37 stimulates calcium mobilization in CXCR2‐transfected HEK293 cells, CXCR2⁺ THP‐1 cells and monocytes, but not in CXCR1‐transfected HEK293 cells. WKYMVm peptide (ligand for FPR2) does not block LL‐37‐stimulated calcium flux in either THP‐1 (FPR2^?) or monocytes (FPR2^high), further confirming the specificity of LL‐37 for CXCR2 and not FPR2. Among all ligands tested (ATP, BzATP, WKYMVm, CXCL1, and LL‐37), only LL‐37 stimulated migration of monocytes (CXCR2⁺ and FPR2⁺) and migration was inhibited by the CXCR2 inhibitor SB225002. Moreover, CXCR2 but not CXCR1 was internalized in LL‐37‐treated neutrophils. Thus, our data provide evidence that LL‐37 may act as a functional ligand for CXCR2 on human neutrophils.     

Cbl and Akt regulate CXCL8-induced and CXCR1- and CXCR2-mediated chemotaxis

CXCL8 (IL-8) plays an important role in the pathogenesis of a variety of inflammatory diseases. However, little is known about the signaling pathways that regulate CXCL8-induced chemotaxis. Here, we found that CXCL8 treatment of CXCR1- and CXCR2-over-expressing L1.2 cells (CXCR1-L1.2 and CXCR2-L1.2, respectively) induced the phosphorylation of Cbl and Akt. The tyrosine kinase inhibitor Tyrphostin A9, phosphatidylinositol-3 kinase (PI3K) inhibitor LY294002 as well as proteasome inhibitors significantly blocked the CXCL8-induced chemotaxis of L1.2 cells and human neutrophils. We further found that stimulation with CXCL8 enhanced the association of the PI3K subunit p85 with Cbl. Additionally, over-expression of wild-type Cbl and G306E-Cbl (mutation in the tyrosine kinase-binding domain) inhibited chemotaxis by approximately 50% as compared with the vector control, whereas the 70Z mutant (deletion in the RING finger domain) did not reduce migration. However, wild-type Cbl or its mutants had no effect on the CXCL8-induced activation of MAPK, indicating that Cbl specifically modulated CXCL8-induced chemotaxis. Furthermore, over-expression of the kinase-dead Akt mutant decreased CXCL8-induced chemotaxis by 60% and diminished Cbl phosphorylation as compared with the vector control. The CXCL8-induced phosphorylation of Cbl was also reduced when cells were pre-treated with the PI3K inhibitor LY294002. Lastly, we have shown that pre-treatment of L1.2 cells with the proteasome inhibitor Lactacystin blocks CXCL8-induced internalization of the CXCR1 and CXCR2 receptors. These studies provide new information regarding CXCL8-induced signaling pathways that may regulate chemotaxis and receptor internalization.     

转染人CXCR4细胞株的构建及其生物学功能的研究

目的：构建稳定表达人CXCR4基因的L929细胞株，分析CXCR4分子对转基因细胞迁移能力的影响。方法：TRIzol一步法抽提人外周血单个核细胞（PBMC）总RNA，RTPCR扩增出CXCR4基因，双酶切装入逆转录病毒载体pEGZTerm，与辅助病毒载体用脂质体法共转染包装细胞293T，用其培养上清感染L929细胞72h后，经Zeocin筛选出稳定表达CXCR4分子的L929细胞株；利用微孔隔离小室检测转人CXCR4基因的L929细胞在SDF-1α作用下的迁移能力。结果：构建含CXCR4基因的重组逆转录病毒载体，经转染包装细胞293T后，筛选获得能稳定高表达人CXCR4蛋白的L929转基因细胞，转入人CXCR4基因的L929细胞在SDF-1α作用下介导迁移。结论：成功构建转染人CXCR4细胞株，为肿瘤迁移模型的研究和鼠抗人CXCR4 mAb的制备打下基础。     

Anti-type II collagen antibody accelerates arthritis via CXCR2-expressing cells in IL-1 receptor antagonist-deficient mice

Arthritis can be induced in mice by the injection of anti-type II collagen (anti-CII) Ab and LPS. To elucidate the role of IL-1 receptor antagonist (IL-1ra) in Ab-induced arthritis, WT and IL-1ra(-/-) mice were administered anti-CII Ab and LPS. These IL-1ra(-/-) mice developed severe arthritis even at low doses of anti-CII Ab and LPS, while WT mice did not. The cells that invaded the arthritic joints were mainly Gr-1(+) neutrophils, and the number of the cells in the joints remained high over 4 weeks in the IL-1ra(-/-) mice. KC, a ligand for CXCR2, is found in higher levels in the arthritic paws of IL-1ra(-/-) mice compared with the WT, and most of the cells that infiltrated into the joints of the IL-1ra(-/-) mice were CXCR2-expressing neutrophils. Administration of anti-CXCR2 Ab completely inhibited arthritis development. The anti-CXCR2 Ab decreased the number of neutrophils in the blood and also inhibited the migration of neutrophils to KC. These results suggested that the high susceptibility of IL-1ra(-/-) mice to anti-CII Ab-induced arthritis was due to the higher expression of chemotactic factors like KC and the sustained infiltration of CXCR2-expressing neutrophils into the joints.     

Ascaris suum-derived products induce human neutrophil activation via a G protein-coupled receptor that interacts with the interleukin-8 receptor pathway

Infection with tissue-migrating helminths is frequently associated with intense granulocyte infiltrations. Several host-derived factors are known to mediate granulocyte recruitment to the tissues, but less attention has been paid to how parasite-derived products trigger this process. Parasite-derived chemotactic factors which selectively recruit granulocytes have been described, but nothing is known about which cellular receptors respond to these agents. The effect of products from the nematodes Ascaris suum, Toxocara canis, and Anisakis simplex on human neutrophils were studied. We monitored four parameters of activation: chemotaxis, cell polarization, intracellular Ca(2+) transients, and priming of superoxide anion production. Body fluids of A. suum (ABF) and T. canis (TcBF) induced strong directional migration, shape change, and intracellular Ca(2+) transients. ABF also primed neutrophils for production of superoxide anions. Calcium mobilization in response to A. suum-derived products was completely abrogated by pretreatment with pertussis toxin, implicating a classical G protein-coupled receptor mechanism in the response to ABF. Moreover, pretreatment with interleukin-8 (IL-8) completely abrogated the response to ABF, demonstrating desensitization of a common pathway. However, ABF was unable to fully desensitize the response to IL-8, and binding to CXCR1 or CXCR2 was excluded in experiments using RBL-2H3 cells transfected with the two human IL-8 receptors. Our results provide the first evidence for a direct interaction between a parasite-derived chemotactic factor and the host's chemotactic network, via a novel G protein-coupled receptor which interacts with the IL-8 receptor pathway.     

Differential Interleukin-8 thresholds for chemotaxis and netosis in human neutrophils

In humans, IL-8 (CXCL8) is a key chemokine for chemotaxis of polymorphonuclear leukocytes and monocytes/macrophages when acting on CXCR1 and CXCR2. CXCL8 activity on neutrophils includes chemotaxis and eliciting the extrusion of neutrophil extracellular traps (NETs). In this study, we show that concentrations of IL-8 that induce NETosis surpass in at least one order of magnitude those required to elicit chemoattraction in human neutrophils. IL-8-induced NETosis was less dependent on G-proteins than migration, while extracellular Ca⁺² chelation similarly inhibited both processes. Reactive oxygen species (ROS) were more important for NETosis than for chemotaxis as evidenced by neutralization with N-acetyl -cysteine. Interestingly, selective blockade with anti-CXCR1 mAb inhibited NETosis much more readily than chemotaxis, while pharmacological inhibition of both CXCR1 and CXCR2, or selective inhibition for CXCR2 alone, similarly inhibited both functions. Together, these results propose a model according to which low concentrations of IL-8 in a gradient attract neutrophils to the inflammatory foci, while high receptor-saturating concentrations of IL-8 give rise to NETosis once leukocytes reach the core of the inflammatory insult.     

人趋化因子受体CCR6在HEK293细胞内的稳定表达及其功能分析

目的:构建稳定表达人趋化因子受体6(CCR6)的HEK293细胞株。方法:将CCR6基因和Gα16质粒共转到HEK293细胞中,并挑取稳定表达CCR6基因的HEK293细胞克隆。采用体外趋化实验、钙流实验、RT-PCR、Western blot及免疫荧光染色法,检测CCR6在HEK293细胞表面的表达。结果:经上述实验证实,CCR6基因和Gα16质粒共转染的HEK293细胞上,可稳定表达CCR6,且具有生物学活性。结论:成功地在HEK293细胞表面稳定表达具有生物学活性的CCR6,为研究CCR6的生物学功能及筛选CCR6的拮抗剂奠定了基础。     

SDF-1/CXCR4在滋养层细胞中的表达及其在母-胎免疫耐受中的作用

目的:研究趋化因子SDF1及其配体CXCR4在滋养层细胞中的表达及其在母胎免疫耐受中的作用。方法:取早孕期的绒毛,分离纯化培养绒毛外滋层养细胞(extravilloustrophoblast,EVT),用免疫细胞化学染色法检测SDF1与CXCR4在绒毛中的表达。用流式细胞术筛选源于滋养层细胞高表达CXCR4的绒癌细胞株用于体外微孔隔离室迁移实验,以分析SDF1的趋化活性。用免疫组织化学染色法检测早孕期绒毛及足月妊娠胎盘中SDF1及CXCR4的表达。结果:在EVT中可检出SDF1和CXCR4的表达,在一定范围内,SDF1的趋化活性与其浓度呈正相关(r=0.68,P<0.01)。10μg/L的SDF1趋化作用最强,最大趋化指数CI为1.62±0.12。在早孕期的绒毛及足月胎盘中,滋养层细胞的胞膜和细胞质中均检出SDF1和CXCR4的表达,但在足月胎盘中的表达强度明显低于早孕期的绒毛组织(P<0.01)。结论:SDF1/CXCR4在妊娠中发挥着重要作用,对维系母胎免疫耐受具有重要意义。