Dominance of CCL22 over CCL17 in induction of chemokine receptor CCR4 desensitization and internalization on human Th2 cells

Chemokines and their receptors play a pivotal role in controlling T cell trafficking in immunity and inflammation. Two chemokines, CCL17 and CCL22, activate the chemokine receptor CCR4, expressed on functionally distinct subsets of T cells: cutaneous leukocyte-associated antigen (CLA)+ skin-homing, T helper (Th) 2, and CD25+ T suppressor cells. Here, we compared the ability of CCL17 and CCL22 to promote CCR4 internalization as a mechanism of regulation of receptor function on human Th2 cells. We report that CCL22 is a potent and rapid inducer of CCR4 internalization, while CCL17 is not. CCR4 internalization does not require G protein coupling, while being dependent on lipid rafts integrity and clathrin-coated pits functionality. Cell surface disappearance of CCR4 is rapidly reversed upon removal of exogenous ligand by virtue of receptor recycling. CCR4 internalization leads to a loss of functional responsiveness, while recovery of surface expression leads to re-acquisition of chemotactic sensitivity of Th2 cells. The differential CCR4 desensitization and internalization reported here and the distinct expression patterns of CCL17 and CCL22 observed in vivo suggest that while CCL17 may act first on CCR4 at the endothelial surface to promote vascular recognition, CCL22 could subsequently engage the receptor within the tissue microenvironment to guide cellular localization.     

A specific CCR3 chemokine receptor antagonist inhibits both early and late phase allergic inflammation in the conjunctiva

Allergic inflammation manifests as one of a number of diseases, including asthma, dermatitis, food allergy, vernal keratoconjunctivitis, and systemic anaphylaxis. Together these diseases affect nearly 25% of the Western world and are a leading health-care problem. The diseases are often biphasic, with an early phase driven primarily by mast cell degranulation and a late phase characterized by leukocyte recruitment. While chemokines are well known to be critical for leukocyte recruitment, their importance in early-phase reactions is poorly defined. We show here that administration of a single oral dose of a high affinity and highly selective CCR3 antagonist ablates both the early and late phase reactions in a mouse model of allergic conjunctivitis. A direct analysis of mast cells in the conjunctiva demonstrates that antagonism of the CCR3 receptor stabilizes the mast cell in vivo, thereby leading to the impaired early phase reaction. The late phase reaction is also strongly inhibited as characterized by both reduced eosinophilia and neutrophilia. These results constitute the first direct evidence that antagonism of CCR3 has clear potential for the treatment of allergic diseases.     

扰乱昼夜节律对小鼠角膜创伤修复的影响

目的:本研究旨在观察昼夜节律对角膜创伤修复的影响。方法:选用C57BL/6雄性小鼠,在小鼠角膜中央直径为2 mm的圆形区域,用高尔夫样刀机械性去除其上皮层,使用荧光素钠显色创伤面积,动态观察上皮层修复的动力学,并观察白细胞、血小板和分裂细胞的动态变化。结果:全昼(12 h light/12 h light,LL)和全夜(12 h dark/12 h dark,DD)组角膜创伤修复速率小于对照组(12 h light/12 h dark,LD),表现为再上皮化延迟、上皮细胞数量降低、血管扩张直径增大、白细胞和血小板募集的发生延迟,但白细胞和血小板数目显著增多。结论:扰乱昼夜节律延迟炎症反应的发生,但加剧炎症反应;延迟再上皮化过程,最终显著抑制角膜创伤修复过程。     

IL-33 improves wound healing through enhanced M2 macrophage polarization in diabetic mice

IL-33 is a newly discovered member of the IL-1 family and has been identified as a potent inducer of Th2 type immunity. Emerging evidence imply that IL-33 may also act as an alarm to alert the immune system when released by epithelial barrier tissues during trauma or infection. In this study, we further investigate the potential efficacy of IL-33 on dermal wound healing in streptozotocin–induced diabetic mice. A full-thickness skin wound was generated on the back of diabetic mice and treated with IL-33 or vehicle topically. Our data showed that IL-33 delivery contributed to diabetic wound closure with wounds gaping narrower and exhibiting elevated re-epithelialization. IL-33 promoted the new extracellular matrix (ECM) deposition and angiogenesis formation, which indicates an important role of IL-33 on matrix synthesis and neovascularization. Meanwhile, IL-33 accelerated the development of M2 macrophages in wound sites in vivo, and amplified IL-13-induced polarization of bone marrow-derived macrophages toward a M2 phenotype in vitro. Furthermore, IL-33-amplified M2 macrophages augmented the proliferation of fibroblasts and ECM deposition. All together, these results strongly suggest manipulation of IL-33-mediated signal might be a potential therapeutic approach for diabetic skin wounds.     

Comprehensive characterization of myeloid cells during wound healing in healthy and healing-impaired diabetic mice

Wound healing involves the concerted action of various lymphoid and in particular myeloid cell populations. To characterize and quantitate different types of myeloid cells and to obtain information on their kinetics during wound healing, we performed multiparametric flow cytometry analysis. In healthy mice, neutrophil numbers increased early after injury and returned to near basal levels after completion of healing. Macrophages, monocyte-derived dendritic cells (DCs), and eosinophils were abundant throughout the healing phase, in particular in early wounds, and Langerhans cells increased after wounding and remained elevated after epithelial closure. Major differences in healing-impaired diabetic mice were a much higher percentage of immune cells in late wounds, mainly as a result of neutrophil, macrophage, and monocyte persistence; reduced numbers and percentages of macrophages and monocyte-derived DCs in early wounds; and of Langerhans cells, conventional DCs, and eosinophils throughout the healing process. Finally, unbiased cluster analysis (PhenoGraph) identified a large number of different clusters of myeloid cells in skin wounds. These results provide insight into myeloid cell diversity and dynamics during wound repair and highlight the abnormal inflammatory response associated with impaired healing.     

T细胞相关趋化因子及受体的研究进展

T细胞在发育、成熟、活化及发挥生物学效应的各个阶段表达不同的趋化因子受体。T细胞相关趋化因子及其受体的表达在不同的细胞类群上具有时相和分布的差异,并通过趋化因子与其受体特异性结合的模式,参与T细胞的发育过程,调控细胞的定向迁移,从而影响局部甚至整个机体的免疫状态。此外,它还在炎症、感染、肿瘤、自身免疫疾病等众多病理生理的过程中发挥重要作用。在这一领域的深入研究将为相关疾病的预防和治疗提供新的思路和途径。     

单核-巨噬细胞的异质性及其对创面愈合的调控研究进展

单核吞噬细胞系统(MPS)主要由骨髓中单核细胞前体、外周血中的单核细胞、组织中的巨噬细胞和树突状细胞(DC)组成。其中,巨噬细胞和DC分布在机体的多个组织器官,发挥免疫监控和抵御病原体入侵的作用。然而,不同部位的这些细胞在组织形态和功能上存在一定差异,即使是同一器官中的巨噬细胞也不尽相同。皮肤中的单核-巨噬细胞主要包括表皮中的朗格汉斯细胞以及真皮中的巨噬细胞和真皮树突状细胞(dDC),它们共同参与调控创面愈合过程中的炎症反应、肉芽组织生成和组织重塑,达到促进创面愈合的作用。     

Increased inflammation in mice deficient for the chemokine decoy receptor D6

Chemokines are chemotactic cytokines with a key role in the control of cell trafficking and positioning under homeostatic and inflammatory conditions. D6 is a promiscuous 7-transmembrane-domain receptor expressed on lymphatic vessels which recognizes most inflammatory, but not homeostatic, CC chemokines. In vitro experiments demonstrated that D6 is unable to signal after ligand engagement, and it is structurally adapted to sustain rapid and efficient ligand internalization and degradation. These unique functional properties lead to the hypothesis that D6 may be involved in the control of inflammation by acting as a decoy and scavenger receptor for inflammatory chemokines. Consistent with this hypothesis, here we report that D6(-/-) mice showed an anticipated and exacerbated inflammatory response in a model of skin inflammation. Moreover, the absence of D6 resulted in increase cellularity and inflammatory-chemokine levels in draining lymph nodes. Thus, D6 is a decoy receptor structurally adapted and strategically located to tune tissue inflammation and control transfer of inflammatory chemokines to draining lymph nodes.     

趋化因子及其受体在炎症中作用的研究进展

趋化因子是能够激发白细胞趋化性的小分子分泌性蛋白质,是可受化学诱导物及细胞因子调节、并能刺激细胞趋化运动的一类细胞因子.趋化因子将循环中的淋巴细胞募集到组织损伤或炎症反应部位.早期对趋化因子的研究是基于其在炎症中的功能.最近发现趋化因子及其受体和机体内单核细胞的迁移,适应性免疫应答以及多种疾病的发病机理相关.趋化因子受体作为炎症和免疫应答的调控分子而成为多种药物的靶向分子.临床上已经开始利用趋化因子的拈抗剂治疗炎症疾病,本篇旨在阐述趋化因子及其受体在炎症疾病中的作用以及这些趋化因子在临床上的应用.     

中性粒细胞胞外诱捕网在创面愈合过程中作用的研究进展

创面愈合与免疫及炎症反应密切相关。中性粒细胞作为炎症反应的主要效应细胞之一,已被证明在糖尿病足等创面愈合的病理生理过程中起着重要的作用。尤其是新近研究发现中性粒细胞在炎症、损伤等的刺激下,可以通过释放中性粒细胞胞外诱捕网(NET),抑制或阻碍创面的愈合,在创面愈合过程中起着重要的作用。然而,NET在不同类型的创面愈合中的作用还未完全阐明。本文将围绕免疫反应与炎症反应等在创面愈合中的最新研究进展,就NET在不同类型的创面愈合过程中的作用作一综述。     

趋化因子受体CCR5、CCR7、CXCR3和CXCR6在丙肝患者肝内及外周血CD4+ T淋巴细胞上的表达及其意义

目的比较趋化因子受体CCR5、CCR7、CXCR3和CXCR6在丙肝患者肝内和外周血CD4^＋T淋巴细胞表面表达水平及其意义,同时进一步了解其与肝脏组织学炎症反应的关系.方法采用荧光标记抗趋化因子受体的单克隆抗体对肝内及外周血中CD4^＋T淋巴细胞表面的趋化因子受体进行染色后,采用9色11参数流式细胞仪LSRⅡ进行检测分析.结果（1）肝内CCR5^＋、CXCR3^＋或/和CXCR6^＋的CD4^＋T淋巴细胞频数高于外周血（P＜0.001）,而CCR7^＋CD4^＋T淋巴细胞频数低于外周血（P＜0.001）;（2）肝内CCR5^＋或CXCR6^＋的活性（CD38^＋）CD4^＋T淋巴细胞频数高于外周血（P＜0.05）;（3）肝内表达2种或2种以上趋化因子受体CCR5、CXCR3和CXCR6的CD4^＋T淋巴细胞频数明显高于外周血（P＜0.001）,而不表达或仅表达一种上述趋化因子受体CD4^＋T淋巴细胞频数明显低于外周血（P＜0.001）;（3）CCR5和CXCR6在肝内CD4^＋T淋巴细胞表面的表达有中等度相关;（4）肝内组织学炎症明显组表达趋化因子受体CCR5、CXCR3或CXCR6的CD4^＋T淋巴细胞频数高于炎症轻微组.结论趋化因子受体CCR5、CXCR3和CXCR6可能介导CD4^＋T淋巴细胞向肝内迁徙定植,并参与肝脏炎症的病理免疫学反应过程.     

CCR7和VEGF-C蛋白与乳腺癌预后之间的关系

目的:探讨趋化因子受体7(CCR7)及血管内皮生长因子C(VEGF-C)蛋白在乳腺癌组织中的表达水平,并分析二者与乳腺癌预后的关系。方法:采用免疫组织化学技术,联合检测CCR7和VEGF-C蛋白分别在乳腺癌组织及正常乳腺组织中的表达差异情况,并分析二者与乳腺癌各相关临床病理特征之间的关系。采用Kaplan-Meier法来评估CCR7及VEGF-C蛋白的异常表达与乳腺癌患者生存期之间的关系。结果:CCR7蛋白在乳腺癌组织(68%)中的阳性表达率高于正常乳腺组织(30%),差异有统计学显著性(P0.01);而VEGF-C蛋白在乳腺癌组织(71%)中的阳性表达率也明显高于正常乳腺组织(24%),差异也有统计学显著性(P0.01)。且在乳腺癌组织中,CCR7与VEGF-C蛋白的表达呈正相关关系(r=0.613,P0.01)。CCR7和VEGF-C蛋白的高表达均与淋巴结转移和TNM分期有关(P0.05),而与年龄、肿瘤大小、雌激素受体和孕激素受体均无关。CCR7及VEGFC蛋白阳性表达者的生存期低于阴性表达者,两组比较差异有统计学显著性(P0.05)。结论:CCR7与VEGF-C的异常高表达可能与乳腺癌预后关系密切,二者可作为判断乳腺癌预后不良的重要指标之一。     

LPS down-regulates the expression of chemokine receptor CCR2 in mice and abolishes macrophage infiltration in acute inflammation

Interactions between chemokines and their specific receptors are important for leukocyte trafficking. The CC-chemokine monocyte chemoattractant protein-1 (MCP-1) and its specific receptor CCR2 are essential in monocytic infiltration and have been associated with several inflammatory diseases. It has been reported that several endotoxin and proinflammatory cytokines inhibit CCR2 expression in vitro in human monocytes. We report here that lipopolysaccharides (LPS) down-regulated CCR2 expression both in vitro and in vivo. Injection of LPS into mice dramatically reduced the expression of CCR2 on the surface of peripheral blood cells and completely blocked macrophage infiltration into the peritoneal cavity in response to thioglycollate elicitation. In addition, treatment of mice with LPS reduced their efficiency to clear Listeria monocytogenes infection. These results suggest that down-regulation of CCR2 and blockage of monocyte infiltration may contribute to the inhibition of macrophage function in vivo by a low dose of LPS.     

COX-2信号通路及其调控对皮肤伤口愈合的干预研究

目的 通过体外及体内干预实验研究探讨COX-2信号通路对皮肤伤口炎症细胞、新生血管的影响,评价皮肤伤口愈合的情况,为减少伤口瘢痕形成、促进愈合的诊疗方法提供实验依据.方法 采用体外细胞培养划痕试验及小鼠体内实验,运用COX-2选择性抑制剂尼美舒利进行干预,通过伤口皮肤铺片、免疫组化对伤口生长过程中炎症细胞、新生血管、成...     

α7nAChR的激活通过抑制TNF-α表达促进糖尿病小鼠伤口愈合

 目的：观察糖尿病小鼠伤口愈合期间巨噬细胞浸润及肿瘤坏死因子 α（TNF-α）表达特征,探讨α7烟碱型乙酰胆碱受体（α7nAChR）特异性激动剂PNU-282987是否可通过抑制TNF-α表达促进糖尿病小鼠伤口的愈合。方法：(1) 制作糖尿病小鼠切创模型（糖尿病组）,正常小鼠在相同部位制作相同大小创口作为对照（对照组）,分别于切创后1 d、3 d、5 d、10 d、14 d和21 d（每个时间段5只）提取创口样本。免疫组化观察创口中巨噬细胞和成纤维细胞数量,Western blotting检测TNF-α表达水平,Masson染色观察胶原沉积情况。 (2) 在糖尿病小鼠切创后,选择合适的干预时间窗进行PNU-282987干预,然后观察上述指标变化。结果：(1) 与对照组相比,糖尿病组创口愈合明显延迟,在切创初期的伤口中巨噬细胞数量和TNF-α表达水平较低（P<0.05）,而切创5 d后的伤口巨噬细胞数量和TNF-α表达水平显著增加（P<0.05）,成纤维细胞数量和胶原含量减少（P<0.05）。 (2) 在切创5 d后对糖尿病小鼠腹腔注射PNU-282987,可显著减少伤口中TNF-α表达,提高成纤维细胞数量和胶原含量,促进伤口愈合。结论：糖尿病伤口愈合具有炎症反应发生迟但不易消退的特征。在炎症反应明显期激活α7nAChR可抑制TNF-α表达,促进糖尿病小鼠的伤口愈合。     

A unique pattern of up- and down-regulation of chemokine receptor CXCR3 on inflammation-inducing Th1 cells

Chemokine receptor CXCR3 and its CXC ligands play major roles in Th1 cell-induced inflammatory processes. Here, we examined the expression of CXCR3 by TCR-transgenic Th1 lymphocytes that induce ocular inflammation in mice expressing the target antigen in their lenses. The essential role of CXCR3 in this model was indicated by the observation that the ocular inflammation was significantly blocked by an antibody against this receptor. CXCR3 expression by Th1 cells was elevated during their initial activation in culture and further increased during the consecutive incubation with IL-2. However, CXCR3 expression declined dramatically during the ensuing antigenic reactivation, in parallel with down-regulation of its mRNA. Yet, reactivated Th1 cells exhibited the highest degree of pathogenicity when adoptively transferred into recipients. Transferred reactivated Th1 cells proliferated vigorously and re-expressed CXCR3 while residing in the spleen of recipient mice, reaching approximately 85% positivity 4 days post cell transfer when their massive migration to the target eyes began. Importantly, infiltrating Th1 cells underwent profound phenotypic changes in the eye that closely resembled those seen during reactivation of Th1 cells in vitro and included down-regulation of CXCR3. These observations thus show that expression of CXCR3, a major participant in Th1-induced inflammation, fluctuates profoundly during cell activation and migration and is down-regulated upon re-exposure of these cells to the antigen, in vitro or in the target organ.     

HIV-1协同受体CXCR4、CCR5及相关趋化因子SDF-1在胎盘的表达

目的：研究HIV-1协同受体CXCR4、CCR5及CXCR4的特异性配体SDF-1在人胎盘组织的表达，探索HIV-1子宫内垂直传播的分子机制。方法：半定量RT-PCR检测早、中、晚孕期胎盘及早孕滋养细胞CXCR4、CCR5 mRNA水平；免疫组化和免疫细胞化学检测早孕胎盘及原代培养滋养细胞CXCR4、CCR5蛋白表达；原位杂交及免疫组化分析SDF-1在早孕胎盘的表达；ELISA测定滋养细胞SDF-1的动态分泌水平。结果：各孕期胎盘表达CXCR4及CCR5 mRNA；CXCR4蛋白定位于滋养细胞，而CCR5蛋白定位于绒毛基质中。滋养细胞可转录并翻译SDF-1，且能分泌可溶性SDF-1。结论：滋养细胞同时表达CXCR4及SDF-1，SDF-1可能通过降调CXCR4而拮抗X4-HIV-1感染胎儿细胞；R5-HIV-1或许能通过滋养层裂隙感染CCR5^#基质细胞和/或Hotbauer细胞，从而发生子宫内垂直传播。     

Macrophages in skin injury and repair

After recruitment to the wound bed, monocytes differentiate into macrophages. Macrophages play a central role in all stages of wound healing and orchestrate the wound healing process. Their functional phenotype is dependent on the wound microenvironment, which changes during healing, hereby altering macrophage phenotype. During the early and short inflammatory phase macrophages exert pro-inflammatory functions like antigen-presenting, phagocytosis and the production of inflammatory cytokines and growth factors that facilitate the wound healing process. As such, the phenotype of wound macrophages in this phase is probably the classically activated or the so-called M1 phenotype. During the proliferative phase, macrophages stimulate proliferation of connective, endothelial and epithelial tissue directly and indirectly. Especially fibroblasts, keratinocytes and endothelial cells are stimulated by macrophages during this phase to induce and complete ECM formation, reepithelialization and neovascularization. Subsequently, macrophages can change the composition of the ECM both during angiogenesis and in the remodelling phase by release of degrading enzymes and by synthesizing ECM molecules. This suggests an important role for alternatively activated macrophages in this phase of wound healing. Pathological functioning of macrophages in the wound healing process can result in derailed wound healing, like the formation of ulcers, chronic wounds, hypertrophic scars and keloids. However, the exact role of macrophages in these processes is still incompletely understood. For treating wound repair disorders more should be elucidated on the role of macrophages in these conditions, especially their functional phenotype, to find more therapeutic opportunities.This review summarizes macrophage function in skin injury repair, thereby providing more insight in macrophage function in wound healing and possible interventions in this process.     

Chemokines (RANTES and MCP-1) and chemokine-receptors (CCR2 and CCR5) gene polymorphisms in Alzheimer's and Parkinson's disease

Parkinson's disease (PD) is a complex disorder characterized by the progressive degeneration of dopaminergic neurons in the midbrain. Late-onset Alzheimer's disease (LOAD) is the most common cause of dementia in the elderly, affecting about 5% of the population older than 65 years. Several works have demonstrated the involvement of inflammation in the pathogenesis of both, PD and LOAD. Genetic susceptibility to develop PD and LOAD has also been widely recognised. Thus, functional polymorphisms at the genes encoding inflammatory proteins could influence the overall risk of developing these neurodegenerative disorders.

We examined whether DNA-polymorphisms at the genes encoding chemokines MCP-1 (−2518 A/G) and RANTES (−403 A/G), and chemokine receptors 5 (CCR5, Δ32) and 2 (CCR2,V64I), were associated with the risk and/or the clinical outcome of LOAD and PD. A total of 200 PD, 326 LOAD, and 370 healthy controls were genotyped for the four polymorphisms, and genotype frequencies statistically compared.

We did not find significant differences in the frequencies of the different genotypes between both groups of patients and controls. We conclude that the four DNA polymorphisms, which have been associated with several immuno-modulated diseases, did not contribute to the risk of PD or LOAD.     

A time-lapse approach to examine chromium and nickel effects on wound healing in vitro

Chromium and nickel cause allergic contact dermatitis, a common biological skin response to sensitizing agents. This study used a conventional in vitro wounding model to study the impact of sensitizing agents on the innate immune response of human keratinocytes. Experiments were designed to evaluate the involvement of specific Toll-like receptors and metalloproteinases as effectors molecules downstream, at a molecular level. Further, keratinocytes were co-cultured with monocytes (THP-1 cells) to reproduce an inductive stimulus on monocytes made by metals. Human keratinocytes (HaCat) were grown on plates covered with collagen type I, chemically treated, and then mechanically injured with a sterile pipette tip. Restoration of the monolayer integrity was monitored by time-lapse video microscopy. Effector gene expression was evaluated by real-time PCR. The presence of chromium significantly dropped the rate of wound closure, while nickel-induced hyper-proliferation ended in an acceleration of the healing process, an event that does not occur in vivo. This latter outcome led to considering nickel as an unsuitable example for use in the experimental model. Focusing solely on the chromium aspect of this study, RNA profiles of selected molecular markers were generated to ascertain if the detrimental stimulus from chromium was eliminated or persisted both in keratinocytes alone and/or during co-cultures of keratinocytes and monocytes. Monocytes accelerated the process of wound repair. This in vitro experimental model highlighted the involvement of innate immunity in response to chromium and might be useful for test molecules of therapeutic interest for the treatment of skin lesions. However, the experience with nickel reveals that there are limitations to the utility of this wound model system after all.