γδT细胞相关的趋化因子受体

γδT细胞是一群异质性的免疫活性细胞,根据表面标志和功能可将其分为不同亚群。γδT细胞表达的趋化因子受体各异,趋化因子受体的表达与γδT细胞在抗感染、抗肿瘤和自身免疫中的功能发挥密切相关,现就近年来与γδT细胞相关的趋化因子受体研究进展作一综述。     

趋化因子及其受体在连接天然免疫与获得性免疫中的作用

病原侵入组织引起天然免疫中巨噬细胞(Mφ)分泌趋化因子,趋化因子／趋化因子受体的表达与非成熟树突状细胞(DC)的迁移、成熟、归巢以及获得性免疫应答密切相关。整个过程涉及许多趋化因子和趋化因子受体的表达变化,正是这种表达变化的精细调节启动了免疫细胞的定向迁移、归巢和游走,搭起天然免疫和获得性免疫的桥梁。本文综述了趋化因子和趋化因子受体在连接天然免疫和获得性免疫应答中的重要作用。     

趋化因子在HBV感染发病中的作用

乙型肝炎是一种以局部炎性为主的感染性疾病,乙型肝炎病毒（HBV）感染宿主细胞后可诱导宿主细胞中趋化因子分泌及其受体表达,趋化因子／受体的相互作用进一步介导中性粒细胞、淋巴细胞等向炎症部位聚集,参与组织损伤;同时诱导T、B细胞分化成熟,对乙型肝炎的发展与转归、肝组织的损伤与修复有重要影响。HBV引发的慢性乙型肝炎（CHB）以Th1细胞性炎性反应为主,研究表明乙型肝炎中某些趋化因子在肝脏高表达,其受体CXCR3和CCR5在Th1细胞高表达。趋化因子尤其是CXC和CC亚家族趋化因子在趋化Th1细胞中发挥重要的作用：     

趋化因子及趋化因子受体3在自身免疫疾病中的作用

人体在防御和清除入侵病原体等异物时,有一种使白细胞趋集的功能,有一些低分子量的物质能引起这种功能称之为趋化剂或趋化因子。这些小蛋白因其有定向细胞趋化作用而得名。经研究表明,趋化因子受体3（CXCR3）趋化因子可能在自身免疫内分泌疾病中起到致病作用。此外,血清中CXCR3趋化因子的判定可能辅助检测免疫活性。CXCR3和优先参与趋化Th1细胞的因子。该受体连接的趋化因子10（CXCL10）不仅参与白细胞募集,还诱导T细胞增殖的异源体和抗原的刺激。趋化因子10正调节Th1细胞产物并且负调节Th2细胞的产物。免疫反应纤维结合素（INF）产物可增强特异的炎症反应。当被激活或者发现炎症和肿瘤细胞后趋化因子受体3-B在内皮细胞中表达并且其结合的趋化因子10,趋化因子9和趋化因子11激活后产生血管抑制作用。     

趋化因子在病毒感染中的作用及意义

趋化因子是近年发现的一大类结构相似、功能多样的新型分子。其不仅与淋巴细胞迁移、炎症反应、新生血管生成、造血、肿瘤有关,越来越多的证据表明趋化因子在病毒感染的发生、发展中扮演着重要角色。病毒感染宿主细胞后可导致组成性和诱导性趋化因子表达谱的改变,这些表达水平改变了趋化因子通过直接和间接的方式参与了病毒的致病过程;同时某些病毒可编码趋化因子样或趋化因子受体样分子,从而干扰趋化因子网络功能。研究趋化因子在病毒感染中的作用及意义,将有利于阐明在病毒性疾病的发病机制和抗病毒感染所策略的制定,具有重要的理论和应用价值。     

趋化因子CXCL16与临床疾病

趋化因子在T细胞迁移过程中起重要作用,CXCL16是作为磷脂酰丝氨酸和ox-LDL的清道夫受体的多功能趋化因子。血管内皮细胞同时表达功能性地分泌型和膜结合型CXCL16分子,分泌型CXCL16参与激活T淋巴细胞趋化。膜结合型CXCL16作为粘附分子,通过它的趋化因子活性区参与活化T淋巴细胞与血管内皮细胞之间的识别和直接粘附;促进大量的特异性炎症细胞浸润。研究证明趋化因子CXCL16在多种临床疾病中扮演起重要作用。本文综述了CXCL16与临床疾病的关系及其研究进展。     

TGF-β 1 对人蜕膜基质细胞中趋化因子及其受体表达的影响

为探讨转化生长因子β1(TGF-β1)在蜕膜基质细胞中发挥免疫调节作用的机制,本研究以人妊娠初期的蜕膜基质细胞为研究对象,经0 ng/ml、1 ng/ml、5 ng/ml和10 ng/ml的TGF-β1处理后,运用RT-PCR方法检测趋化因子mRNA的表达,Western-blot检测趋化因子蛋白质的表达。结果表明:在mRNA水平和蛋白水平,高浓度的TGF-β1能够显著的下调蜕膜基质细胞中趋化因子配体CX3CL1、CXCL12和CXCL16的表达,有意义的上调趋化因子受体CXCR4和CXCR6的表达。研究结果提示,TGF-β1对趋化因子配体/受体有显著的调节作用,并通过趋化因子参与母胎界面的免疫调节。     

The Effect of TGF-β1 on Expression of Chemokine and Its Receptor in Human Decidual Stromal Cells

为探讨转化生长因子β1(TGF-β1)在蜕膜基质细胞中发挥免疫调节作用的机制,本研究以人妊娠初期的蜕膜基质细胞为研究对象,经0 ng/ml、1 ng/ml、5 ng/ml和10 ng/ml的TGF-β1处理后,运用RT-PCR方法检测趋化因子mRNA的表达,Western-blot检测趋化因子蛋白质的表达.结果表明:在mRNA水平和蛋白水平,高浓度的TGF-β1能够显著的下调蜕膜基质细胞中趋化因子配体CX3CL1、CXCL12和CXCL16的表达,有意义的上调趋化因子受体CXCR4和CXCR6的表达.研究结果提示,TGF-β1对趋化因子配体/受体有显著的调节作用,并通过趋化因子参与母胎界面的免疫调节.     

IL-31及其受体研究进展

IL-31是一种最近被发现的细胞因子,主要由活化的Th2细胞产生.其功能受体是由IL-31R和OSMR两个亚基组成的异源二聚体复合物.上皮细胞和角质化细胞能组成性地表达这两种受体亚基,而单核细胞只有在活化状态下才能表达.IL-31通过其受体可以激活JAK-STAT、MAPK和PI3K/Akt三条信号通路,在皮炎等疾病中发挥作用,同时还具有调节抗原递呈、造血作用、细胞增殖及迁移,诱导趋化因子表达等生物学活性.     

CXCR3及其配体介导的抗病毒免疫

CXCR3是ELR阴性的CXC亚家族趋化因子MIG、IP10及ITAC共用的受体,主要在活化的Th1细胞表达.MIG、IP10及ITAC作为CXCR3的配体,通过趋化及活化表达CXCR3的细胞而参与疾病的发生和发展.在病毒感染过程中CXCR3与其配体相互作用,介导抗病毒细胞免疫应答的同时,可能导致病毒感染的器官免疫病理性损伤.     

Roles of SLC/CCL21 and CCR7 in human kidney for mesangial proliferation, migration, apoptosis, and tissue homeostasis

The release of chemokines by intrinsic renal cells is an important mechanism for the regulation of leukocyte trafficking during renal inflammation. The expression of chemokine receptors by intrinsic renal cells such as mesangial cells (MC) suggests an expanded role for chemokine-chemokine receptor biology in local immunomodulation and potentially glomerular homeostasis. By immunohistochemistry we found the chemokine receptor CCR7 expressed in a mesangial pattern while the CCR7 ligand SLC/CCL21 showed a podocyte-specific expression. CCR7 expression was further characterized by RT-PCR, RNase protection assays, and FACS analysis of cultured human MC, and was found to be constitutively present. Real-time PCR of microdissected glomeruli confirmed the expression of SLC/CCL21. A functional role for CCR7 was demonstrated for human MC migration and proliferation. A protective effect of SLC/CCL21 was shown for MC survival in Fas Ab-induced apoptosis. Finally, "wound healing" was enhanced in the presence of SLC/CCL21 in an in vitro injury model. The constitutive glomerular expression of CCR7 and its ligand SLC/CCL21 in adjacent cell types of the human kidney suggests novel biological functions of this chemokine/chemokine receptor pair and a potential role in processes involved in glomerular homeostasis and regeneration.     

CXCL16 in kidney and cardiovascular injury

CXC chemokine ligand 16 (CXCL16) is a CXC soluble chemokine, an adhesion molecule and a cell surface scavenger receptor. CXCL16 regulates inflammation, tissue injury and fibrosis. Parenchymal renal cells, vascular wall cells, leukocytes and platelets express and/or release CXCL16 under the regulation of inflammatory mediators. CXCL16 expression is increased in experimental and human nephropathies. Targeting CXCL16 protected from experimental glomerular injury or interstitial fibrosis. Conflicting results were reported for experimental cardiovascular injury. High circulating CXCL16 levels are associated to human kidney and cardiovascular disease and urinary CXCL16 may increase in kidney injury. In conclusion, mounting evidence suggests a role of CXCL16 in kidney and cardiovascular disease. However, a better understanding is still required before exploring CXCL16 targeting in the clinic.     

Delayed blockade of the kinin B1 receptor reduces renal inflammation and fibrosis in obstructive nephropathy

Renal fibrosis is the common histological feature of advanced glomerular and tubulointerstitial disease leading to end-stage renal disease (ESRD). However, specific antifibrotic therapies to slow down the evolution to ESRD are still absent. Because persistent inflammation is a key event in the development of fibrosis, we hypothesized that the proinflammatory kinin B1 receptor (B1R) could be such a new target. Here we show that, in the unilateral ureteral obstruction model of renal fibrosis, the B1R is overexpressed and that delayed treatment with an orally active nonpeptide B1R antagonist blocks macrophage infiltration, leading to a reversal of the level of renal fibrosis. In vivo bone marrow transplantation studies as well as in vitro studies on renal cells show that part of this antifibrotic mechanism of B1R blockade involves a direct effect on resident renal cells by inhibiting chemokine CCL2 and CCL7 expression. These findings suggest that blocking the B1R is a promising antifibrotic therapy.     

Considering TWEAK as a target for therapy in renal and vascular injury

TWEAK is a cytokine of the TNF superfamily that activates the Fn14 receptor. TWEAK may regulate cell proliferation, cell death, cell differentiation, angiogenesis and inflammation. The expression of TWEAK and Fn14 is increased during vascular and renal injury. Inflammatory cytokines increase Fn14 receptor expression in tubular and vascular smooth muscle cells. Moreover, TWEAK induces tubular cell apoptosis under proinflammatory conditions. TWEAK itself contributes to renal and vascular inflammation by promoting chemokine and inflammatory cytokine secretion. Confirmation of its role in acute kidney injury and atherosclerotic lesions formation came from functional studies in experimental animal models. The available evidence suggests that TWEAK might be a target for therapeutic intervention in renal and vascular injury and its role in different forms of tissue damage should be further explored.     

Uropathogenic Escherichia coli as a model of host-parasite interaction

Resistance to mucosal infection varies greatly in the population, but the molecular basis of disease susceptibility is often unknown. Studies of host-pathogen infections are helpful to identify virulence factors, which characterise disease isolates, and successful defence strategies of hosts that resist infection. In the urinary tract infection (UTI) model, we have identified crucial steps in the pathogen-activated innate host response, and studied the genetic control of these activation steps. Furthermore, genetic variation in the innate host-response defence is investigated as a basis of disease susceptibility. The Toll-like receptor 4 (TLR4) controls initial mucosal response to uropathogenic Escherichia coli (UPEC). Bacterial TLR4 activation in epithelial cells leads to chemokine secretion and neutrophil recruitment and TLR4 mutant mice develop an asymptomatic carrier state. The chemokine receptor CXCR1 determines the efficiency of neutrophil migration and activation, and thus of bacterial clearance. CXCR1 mutant mice become bacteremic and develop renal scars and studies in UTI prone children have detected low CXCR1 expression, suggesting that CXCR1 is also essential for human disease susceptibility.     

Up-regulation of early growth response gene-1 via the CXCR3 receptor induces reactive oxygen species and inhibits Na+/K+-ATPase activity in an immortalized human proximal tubule cell line

The CXCR3 chemokine receptor, a member of the CXCR family, has been linked to a pathological role in autoimmune disease, inflammatory disease, allograft rejection, and ischemia. In the kidney, expression of the CXCR3 receptor and its ligands is up-regulated in states of glomerulonephritis and in allograft rejection, but little is known about the expression and functional role the CXCR3 receptor might play. Here, we study the function of the CXCR3 chemokine receptor in an immortalized human proximal tubular cell line (IHKE-1). Stimulation of the CXCR3 receptor by its selective agonist monokine induced by IFN-gamma leads via a Ca(2+)-dependent mechanism to an up-regulation of early growth response gene (EGR)-1. Overexpression of EGR-1 induces down-regulation of copper-zinc superoxide dismutase and manganese superoxide dismutase and stimulates the generation of reactive oxygen species (ROS) via the NADH/NADPH-oxidase system. EGR-1 overexpression or treatment with monokine induced by IFN-gamma resulted in a ROS-dependent inhibition of basolateral Na(+)/K(+)-ATPase activity, compromising sodium transport in these cells. Thus, activation of the CXCR3 receptor in proximal tubular cells might disturb natriuresis during inflammatory and ischemic kidney disease via EGR-1-mediated imbalance of ROS.     

CCR5 deficiency aggravates crescentic glomerulonephritis in mice

The chemokine receptor CCR5 is predominantly expressed on monocytes and Th1-polarized T cells, and plays an important role in T cell and monocyte recruitment in inflammatory diseases. To investigate the functional role of CCR5 in renal inflammation, we induced a T cell-dependent model of glomerulonephritis (nephrotoxic serum nephritis) in CCR5(-/-) mice. Induction of nephritis in wild-type mice resulted in up-regulation of renal mRNA expression of the three CCR5 chemokine ligands, CCL5 (15-fold), CCL3 (4.9-fold), and CCL4 (3.4-fold), in the autologous phase of the disease at day 10. The up-regulated chemokine expression was paralleled by infiltration of monocytes and T cells, followed by renal tissue injury, albuminuria, and loss of renal function. Nephritic CCR5(-/-) mice showed a 3- to 4-fold increased renal expression of CCL5 (61.6-fold vs controls) and CCL3 (14.1-fold vs controls), but not of CCL4, in comparison with nephritic wild-type mice, which was accompanied by augmented renal T cell and monocyte recruitment and increased lethality due to uremia. Furthermore, CCR5(-/-) mice showed an increased renal Th1 response, whereas their systemic humoral and cellular immune responses were unaltered. Because the CCR5 ligands CCL5 and CCL3 also act via CCR1, we investigated the effects of the pharmacological CCR1 antagonist BX471. CCR1 blockade in CCR5(-/-) mice significantly reduced renal chemokine expression, T cell infiltration, and glomerular crescent formation, indicating that increased renal leukocyte recruitment and consecutive tissue damage in nephritic CCR5(-/-) mice depended on functional CCR1. In conclusion, this study shows that CCR5 deficiency aggravates glomerulonephritis via enhanced CCL3/CCL5-CCR1-driven renal T cell recruitment.     

Chemokine amplification in mesangial cells.

Mesangial cells are specialized cells of the renal glomerulus that share some properties of vascular smooth muscle cells and macrophages. They are implicated in the pathogenesis of many forms of nephritis. The murine CXC-chemokines macrophage inflammatory protein-2 (MIP-2) and KC induce migration of mouse mesangial cells. Mesangial cells also exhibit a unique chemokine feedback mechanism. Treatment with nanomolar concentrations of MIP-2 or KC markedly up-regulates monocyte chemoattractant protein-1 and RANTES expression in mesangial cells. Autoinduction of MIP-2 and KC mRNA was also noted. Low levels of MIP-1alpha, MIP-1beta, and IFN-gamma-inducible protein-10 were induced following treatment with higher doses of MIP-2 or KC. These effects are specific to mesangial cells, as MIP-2 or KC treatment of renal cortical epithelial cells or peritoneal macrophages failed to induce chemokine production. This cascade of chemokine interactions may contribute to renal infiltration and leukocyte activation. The abilities of MIP-2 or KC to stimulate their own synthesis may also contribute to the maintenance and chronic course of glomerular inflammation. The mesangial cell receptor for MIP-2 and/or KC is unknown but is not CXC-chemokine receptor-2.     

The Multiple Chemokine–Binding Bovine Herpesvirus 1 Glycoprotein G (BHV1gG) Inhibits Polymorphonuclear Cell but Not Monocyte Migration into Inflammatory Sites

Chemokines facilitate the recruitment of inflammatory cells into tissues, contributing to target organ injury in a wide range of inflammatory and autoimmune diseases. Targeting either single chemokines or chemokine receptors alters the progression of disease in animal models of rheumatoid arthritis and lupus with varying degrees of efficacy, but clinical trials in humans have been less successful. Given the redundancy of chemokine–chemokine receptor interactions, targeting of more than one chemokine may be required to inhibit active inflammatory disease. To test the effects of multiple chemokine blockade in inflammation, we generated an adenovirus expressing bovine herpesvirus 1 glycoprotein G (BHV1gG), a viral chemokine antagonist that binds to a wide spectrum of murine and human chemokines, fused to the fragment crystallizable (Fc) portion of murine immunoglobulin (IgG)2a. Administration of the adenovirus significantly inhibited thioglycollate-induced migration of polymorphonuclear leukocytes into the peritoneal cavity of BALB/c mice and reduced both clinical severity and articular damage in K/BxN serum transfer-induced arthritis. However, treatment with BHV1gG-Ig fusion protein did not prevent monocyte infiltration into the peritoneum in the thioglycollate model and did not prevent renal monocyte infiltration or nephritis in lupus-prone NZB/W mice. These observations suggest that the simultaneous inhibition of multiple chemokines by BHV1gG has the potential to interfere with acute inflammatory responses mediated by polymorphonuclear leukocytes, but is less effective in chronic inflammatory disease mediated by macrophages.     

Cilia‐localized LKB1 regulates chemokine signaling,macrophage recruitment,and tissue homeostasis in the kidney

Polycystic kidney disease (PKD) and other renal ciliopathies are characterized by cysts, inflammation, and fibrosis. Cilia function as signaling centers, but a molecular link to inflammation in the kidney has not been established. Here, we show that cilia in renal epithelia activate chemokine signaling to recruit inflammatory cells. We identify a complex of the ciliary kinase LKB1 and several ciliopathy‐related proteins including NPHP1 and PKD1. At homeostasis, this ciliary module suppresses expression of the chemokine CCL2 in tubular epithelial cells. Deletion of LKB1 or PKD1 in mouse renal tubules elevates CCL2 expression in a cell‐autonomous manner and results in peritubular accumulation of CCR2⁺ mononuclear phagocytes, promoting a ciliopathy phenotype. Our findings establish an epithelial organelle, the cilium, as a gatekeeper of tissue immune cell numbers. This represents an unexpected disease mechanism for renal ciliopathies and establishes a new model for how epithelial cells regulate immune cells to affect tissue homeostasis.