Crucial Involvement of the CCR2/CCL2 Interactions in Azoxymethane/Dextran Sodium Sulfate-induced Colon Carcinogenesis in Mice

Azoxymethane (AOM) administration followed by repetitive dextran sulfate sodium (DSS) ingestion causes chronic colonic inflammation with macrophage infiltration and enhanced expression of a macrophage-tropic chemokine, CCL2, in wild-type (WT) mice. These mice eventually develop multiple colon tumors. In contrast, mice deficient in CCR2, a specific receptor for CCL2, exhibited less macrophage infiltration and attenuated tumor formation. WT mice transplanted with CCR2-deficient bone marrow developed fewer tumors after AOM and DSS treatment than either WT or CCR2-deficient mice transplanted with WT bone marrow. Furthermore, when injected to WT mice with multiple colon tumors, a CCL2 antagonist expression vector attenuated macrophage and granulocyte infiltration, and eventually reduced the numbers and sizes of tumors. These results implied the crucial involvement of the CCL2-CCR2 interactions in the development and progression of colon carcinoma associated with chronic inflammation.

     

Immunomodulatory Effects of Withania Somnifera on Azoxymethane Induced Experimental Colon Cancer in Mice

The efficacy of Withania somnifera on immunomodulation was tested in experimental azoxymethane induced colon cancer in mice. Azoxymethane is a potential carcinogen to induce the colon cancer in Swiss albino mice. Azoxymethane 15 mg/kg body weight was injected intraperitoneally once a week for 28 days. The colon cancer was confirmed by the appearance of aberrant crypt foci (ACF) in the colons of the experimental mice. The progression in colon tumor development was correlated with the appearance of the histological biomarker and ACF. Azoxymethane induced colon cancer animals were treated with 400 mg/kg body weight of W. somnifera extract once a week for four weeks orally. After the experimental period, the animals were sacrificed and analyzed for immunocompetent cells, immune complexes and immunoglobulins. W. somnifera significantly altered the level of leucocytes, lymphocytes, neutrophils, immune complexes and immunoglobulins (Ig) A, G and M. The azoxymethane induced colon cancer and immune dysfunction was better controlled by W. somnifera. These results suggested that the immunomodulatory effects of W. somnifera could be useful in the treatment of colon cancer.     

Involvement of CC chemokines in gammadelta T lymphocyte trafficking during allergic inflammation: the role of CCL2/CCR2 pathway

In the present study, we show that the intra-thoracic injection of ovalbumin (OVA, 12.5 microg per cavity) into C57BL/10 mice induced a significant increase in gammadelta T lymphocyte numbers in the pleural cavity, blood and thoracic lymph node of challenged mice. Such increase was significant within 12 h, peaked within 48 h and returned to basal counts within 120 h. Levels of CC chemokine ligand (CCL)-2/monocyte chemotactic protein-1, CCL5/regulated upon activation, normal T cell expressed and secreted, CCL3/macrophage inflammatory protein-1 alpha and CCL25/thymus-expressed chemokine were above control values in pleural washes recovered 24 h after OVA challenge (OPW) and were likely produced by pleural macrophages and mesothelial cells. Antigenic challenge also induced an up-regulation in CC chemokine receptor (CCR)-2, CCR5 and CCR9 on gammadelta T cells from pleural cavities, blood and lymph nodes, suggesting that cells found in mice pleural cavity migrate from secondary lymphoid organs into the inflammatory site via blood stream. The in vitro neutralization of CCL2 (but not of CCL3, CCL5 or CCL25) abrogated OPW-induced gammadelta T lymphocyte transmigration. Confirming such results, the in vivo administration of alpha-CCL2 mAb inhibited gammadelta T lymphocyte accumulation in the pleural cavity of challenged mice, whereas the blockade of CCL3, CCL5 or CCL25 showed no effect on gammadelta T cell mobilization. In addition, OVA challenge failed to induce gammadelta T lymphocyte accumulation in the pleural cavity of C57BL/6 CCR2 knockout mice, which also showed decreased numbers of these cells in blood and lymph nodes when compared with wild-type mice. Overall, such results demonstrate that CCR2/CCL2 pathway is crucial for gammadelta T lymphocyte mobilization during the allergic response.     

Enoxaparin Improves the Course of Dextran Sodium Sulfate-Induced Colitis in Syndecan-1-Deficient Mice

Syndecan-1 (Sdc1) plays a major role in wound healing and modulates inflammatory responses. Sdc1 expression is reduced in lesions of patients with ulcerative colitis. The aim of this study was to investigate the role of Sdc1 in murine dextran sodium sulfate (DSS)-induced colitis. DSS colitis was induced in Sdc1-deficient (knockout (KO)) and wild-type mice by oral administration of 3% DSS. KO mice exhibited a significantly increased lethality as compared with wild-type controls (61 versus 5%, P < 0.05). Impaired mucosal healing and prolonged recruitment of inflammatory cells in KO mice were accompanied by significant up-regulation of tumor necrosis factor-α, CC chemokine ligand 3/macrophage inflammatory protein-1α, and vascular cell adhesion molecule-1, as determined by histological correlation between 0 and 15 days after colitis induction, TaqMan low-density array analysis, and quantitative real-time PCR. Treatment from days 7 through 14 with enoxaparin, a functional analogue of the Sdc1 heparan sulfate chains, significantly reduced lethality of KO mice due to DSS-induced colitis, which was correlated with improved mucosal healing. In vitro, Sdc1-deficient polymorphonuclear cells displayed increased adhesion to endothelial cells and intercellular adhesion molecule-1, and enoxaparin reverted adhesion to wild-type levels. Small interfering RNA-mediated knockdown of Sdc1 expression resulted in reduced basic fibroblast growth factor-mediated mitogen-activated protein kinase signaling and reduced Caco-2 cell proliferation. We conclude that Sdc1 has a protective effect during experimental colitis. The modification of missing Sdc1 function by heparin analogues may emerge as a promising anti-inflammatory approach.Syndecan-1 (Sdc1) is the most important representative of the heparan sulfate proteoglycans (HSPGs) covering epithelial cell surfaces.¹ It serves multiple biological roles, such as cell-matrix interactions, modulation of inflammatory responses, tumorigenesis, and wound healing.^2–4 The highly conserved cytoplasmic domains of Sdc1 interact with scaffolding proteins and participate in integrin-mediated signaling events, thus providing a physical and functional link to the cytoskeleton. In addition, most of the extracellular-binding interactions are mediated by the heparan sulfate chains, which are structurally and functionally related to heparin, an extensively sulfated and epimerized derivative of heparan sulfate.¹ Sdc1 serves as a coreceptor for several tyrosine kinase receptors. For example, it increases the activity of the complex of basic fibroblast growth factor (bFGF) and the FGF receptor and, therefore, contributes to improved wound healing via stimulation of keratinocyte proliferation.^1,5 A role for Sdc1 in wound repair in vivo has been demonstrated in Sdc1-deficient (Sdc1-knockout (KO)) mice, which show delayed skin and corneal wound healing⁵ and functionally adverse repair following experimental myocardial infarction due to dysregulation of chemokine expression and matrix metalloproteinase-mediated tissue remodeling.⁶ Sdc1 forms chemotactic gradients due to binding of chemokines on heparan sulfate chains of the molecule. Therefore, Sdc1 is able to act as coreceptor for chemokine signaling.^7,8 In addition, endothelial leukocyte recruitment and extravasation is modulated by Sdc1, possibly via interference with heparin-binding adhesion molecule function.^9–12Day et al¹³ described in 1999 a reduced expression of Sdc1 in patients with ulcerative colitis, which was linked to disrupted healing of colonic ulcers. In addition, this group demonstrated the benefit of the Sdc1 ectodomain for the FGF-induced proliferation of intestinal epithelial cell lines in vitro. The function of Sdc1 could be restored with heparin, representing a highly sulfated and epimerized form of heparan sulfate, the major functional constituent of the Sdc1 ectodomain.Heparin sees widespread use as anticoagulant drug based on its antithrombin III-activating properties. Enoxaparin, is a low molecular weight heparin with similar features in vitro and in vivo like heparin; however, it exhibits a more favorable pharmacological side effect profile. Both low molecular weight heparins (enoxaparin) as well as heparin were recently found to possess anti-inflammatory properties.¹⁴The hypothesis of Sdc1 being involved in the pathogenesis of ulcerative colitis is underlined by multiple clinical observations of patients who have been treated with heparins for different reasons.¹⁵ In a number of cases, this treatment has lead to an improved course of disease. A limited number of uncontrolled clinical trials with heparins in the treatment of low to medium active ulcerative colitis showed a variable outcome,^16–18 which may be explained by variations in treatment regimes that may have failed to include the optimal dose, class of heparin, and mode of delivery. For example, most studies have involved either i.v. or s.c. delivery of heparin, whereas a more appropriate mode of delivery for stimulating mucosal healing might be the topical application or microsphere-mediated delivery of heparin.^14,15 Furthermore, the outcome of heparin therapy may depend on the degree to which Sdc1 expression is reduced in inflammatory bowel disease (IBD) patients.¹⁹Moreover, the expression of Sdc1 and the proinflammatory cytokine tumor necrosis factor-α (TNF-α) are inversely correlated in the colonic mucosa of patients with Crohn''s disease,²⁰ and a reduction of Sdc1 expression has been shown to result in increased TNF-α signaling in an in vitro model of protein-losing enteropathy,^19,21 further suggesting a regulatory role for Sdc1 in proinflammatory cytokine signaling.In this study, our goal was to characterize the impact of a Sdc1 deficiency on the dextran sodium sulfate (DSS)-induced colitis of the mouse. Furthermore, the efficacy of low molecular weight heparin to restore altered wound healing was studied in vivo. In addition, in vitro trials were performed to study the role of Sdc1 deficiency in the adhesion and transmigration of leukocytes under inflammatory conditions.     

CCR2、 CCL5、 CCR5和CCL1基因多态性与中国汉族儿童结核病易感性的关联研究

目的 探讨CCR2、CCL5、CCR5和CCL1的基因多态性与中国汉族儿童结核病易感性的关系.方法 收集353例汉族儿童结核病患者,以同期查体的400名儿童作为对照,采用病例对照研究,应用高通量MassARRAY技术对于CCR2、CCL5、CCR5和CCL1基因的SNP位点进行基因分型研究.结果 CCR2、CCL5、CCR5和CCL1基因SNP位点的等位基因、基因型以及单体型在结核病组和对照组的分布差异均无统计学意义（P＞0.05）.结论 CCR2、CCL5、CCR5和CCL1的基因多态性与中国汉族儿童结核病易感不存在相关性.     

Role of CCL25/CCR9 in immune homeostasis and disease

Chemokines constitute a large family of low-molecular-weight proteins (～10 kDa in size), recognized primarily for their role in directing leukocyte migration under both homeostatic and inflammatory settings. The chemokine CCL25 displays a unique and highly restricted expression pattern compared with other chemokine family members. In the steady state, CCL25 is expressed at high levels primarily in the thymus and small intestine, while its sole functional receptor, CCR9, is expressed on subsets of developing thymocytes and intestinal lymphocytes. Mice that are deficient in CCR9 show relatively normal thymocyte development; however, in competitive transfer experiments, CCR9^-/- bone-marrow cells are severely disadvantaged in their ability to generate mature T cells compared with wildtype cells. Indeed, expression data and analysis of genetically modified mice suggest that CCL25/CCR9 may be involved in multiple stages of thymocyte development. Recent in vivo studies have demonstrated a role for CCL25/CCR9 in mediating lymphocyte recruitment to the small intestine and in the development of the small intestinal T-cell receptor-γδ T-cell compartment. Finally, CCL25 is expressed in the small intestine of Crohn’s disease patients and, in certain inflammatory conditions, outside the small intestine. Together, these results suggest an important role for CCL25/CCR9 in T-cell development and small intestinal immunity and suggest that targeting the CCL25/CCR9 pathway may provide a means to modulate small intestinal immune responses.     

Differential roles of CCL2 and CCR2 in host defense to coronavirus infection

The CC chemokine ligand 2 (CCL2, monocyte chemoattractant protein-1) is important in coordinating the immune response following microbial infection by regulating T cell polarization as well as leukocyte migration and accumulation within infected tissues. The present study examines the consequences of mouse hepatitis virus (MHV) infection in mice lacking CCL2 (CCL2(-/-)) in order to determine if signaling by this chemokine is relevant in host defense. Intracerebral infection of CCL2(-/-) mice with MHV did not result in increased morbidity or mortality as compared to either wild type or CCR2(-/-) mice and CCL2(-/-) mice cleared replicating virus from the brain. In contrast, CCR2(-/-) mice displayed an impaired ability to clear virus from the brain that was accompanied by a reduction in the numbers of antigen-specific T cells as compared to both CCL2(-/-) and wild-type mice. The paucity in T cell accumulation within the central nervous system (CNS) of MHV-infected CCR2(-/-) mice was not the result of either a deficiency in antigen-presenting cell (APC) accumulation within draining cervical lymph nodes (CLN) or the generation of virus-specific T cells within this compartment. A similar reduction in macrophage infiltration into the CNS was observed in both CCL2(-/-) and CCR2(-/-) mice when compared to wild-type mice, indicating that both CCL2 and CC chemokine receptor 2 (CCR2) contribute to macrophage migration and accumulation within the CNS following MHV infection. Together, these data demonstrate that CCR2, but not CCL2, is important in host defense following viral infection of the CNS, and CCR2 ligand(s), other than CCL2, participates in generating a protective response.     

Thymic Involution Correlates with Severe Ulcerative Colitis Induced by Oral Administration of Dextran Sulphate Sodium in C57BL/6 Mice but not in BALB/c Mice

There is accumulating evidence to support the interactions between psychological stress and inflammatory bowel disease (IBD). In order to elucidate the relationship between psycoimmunological stress and IBD, we examined the alteration of immune system during the disease course of experimental Ulcerative colitis(UC)-model induced by dextran sulfate sodium (DSS). When C57BL/6 mice were treated with 4.5% DSS, they developed progressive weight loss. In contrast, the same treatment applied to BALB/c mice led to a small weight loss from which they soon recovered. Surprisingly, we found significant involution of the thymus and a reduction in the number of double positive thymocytes in DSS-treated C57BL/6 mice but not in DSS-treated BALB/c mice. Double negative thymocytes, especially DN1 (CD25-CD44+) and DN2 (CD25+CD44+) thymocytes, were relatively upregulated. The weights of spleens were slightly increased in both C57BL/6 and BALB/c mice following oral administration of DSS. In C57BL/6 spleens, both CD4 and CD8 single positive T cells gradually decreased (day 3), then recovered (day 14) after treatment. Because oral administration causes starvation, we examined the effects of starvation on the thymus and spleen. Although involution of thymus was observed both in starvation and DSS-treatment, the weight of spleen was reduced only in starvation. Also, the population changes in thymocytes in starvation was different from DSS-treatment. The administration of the steroid inhibitor RU486 partially reversed the thymic involution in C57BL/6 mice, thus DSS-treated UC might induce psycoimmunological changes partly through hypothalamic-pituitary-adrenal axis.     

Chemokine CCL2 and its receptor CCR2 are increased in the hippocampus following pilocarpine-induced status epilepticus

Background  

Neuroinflammation occurs after seizures and is implicated in epileptogenesis. CCR2 is a chemokine receptor for CCL2 and their interaction mediates monocyte infiltration in the neuroinflammatory cascade triggered in different brain pathologies. In this work CCR2 and CCL2 expression were examined following status epilepticus (SE) induced by pilocarpine injection.     

CCL2 recruits T cells into the brain in a CCR2‐independent manner

CCL2 is a chemokine that can be induced during neuroinflammation to recruit immune cells, but its role in the central nervous system (CNS) is unclear. Our aim was to better understand its role. We induced CCL2 in CNS of naive CCL2‐deficient mice using intrathecally administered replication‐defective adenovirus and examined cell infiltration by flow cytometry. CCL2 expression induced pronounced and unexpected recruitment of regulatory and IFNγ‐producing T cells to CNS from blood, possibly related to defective egress of monocytes from CCL2‐deficient bone marrow. Infiltration also occurred in mice lacking CCR2, a receptor for CCL2. Expression of another receptor for CCL2, CCR4, and CXCR3, a receptor for CXCL10, which was also induced, were both increased in CCL2‐treated CNS. CCR4 was expressed by neurons and astrocytes as well as CD4 T cells, and CXCR3 was expressed by CD4 and CD8 T cells. Chemokine‐recruited T cells did not lead to CNS pathology. Our findings show a role for CCL2 in recruitment of CD4 T cells to the CNS and show that redundancy among chemokine receptors ensures optimal response.     

间充质干细胞通过CCL5／CCR5信号途径促进骨肉瘤Saos-2细胞迁移和生长

目的研究人间充质干细胞（hMSC）对骨肉瘤Saos-2细胞迁移与增殖的影响及其机制。 方法取传代培养的hMSC和Saos-2细胞,分别制备hMSC条件培养基（MSC-CM）和Saos-2细胞条件培养基（Saos-2-CM）。采用免疫荧光细胞化学方法和双抗体夹心ELISA方法分别检测bMSC CCL5趋化因子的表达及其表达水平,蛋白质免疫印迹方法检测Saos-2细胞CCR5因子的表达。按条件培养基的不同将Saos-2细胞分为4组：含10％胎牛血清的α-MEM培养基（阴性对照）、Saos-2-CM（阳性对照）、MSC-CM、含24ng／ml兔抗人CCL5抗体的MSC-CM（MSC-CM／anti-CCL5 Ab）,应用Transwell实验和噻唑蓝（MTT）法分别检测hMSC对Saos-2细胞迁移与增殖能力的影响。实验均重复3次。 结果免疫荧光细胞化学方法和双抗体夹心ELISA检测显示,hMSCC CL5因子表达阳性且其表达水平为3．68pg／ml。蛋白质免疫印迹检测显示,Saos-2细胞CCR5因子表达阳性。Transwell实验和MTT检测结果显示,MSC-CM能明显促进Saos-2细胞的迁移与增殖,而MSC-CM／anti-CCL5Ab组Saos-2细胞的迁移与增殖能力均明显下降,2组间差异均有统计学意义（分别为P〈0．01,P〈0．05）。结论CCL5／CCR5信号途径在hMSC促进Saos-2细胞迁移与增殖过程中发挥关键作用,抑制CCL5趋化因子的表达可明显降低Saos-2细胞的迁移与增殖能力。     

间充质干细胞通过CCL5/CCR5信号途径促进骨肉瘤Saos-2细胞迁移和生长

目的 研究人间充质干细胞(hMSC)对骨肉瘤Saos-2 细胞迁移与增殖的影响及其机制.方法 取传代培养的hMSC 和Saos-2 细胞,分别制备hMSC 条件培养基(MSC-CM)和Saos-2 细胞条件培养基(Saos-2-CM).采用免疫荧光细胞化学方法 和双抗体夹心ELISA 方法 分别检测hMSC CCL5 趋化因子的表达及其表达水平,蛋白质免疫印迹方法 检测Saos-2 细胞CCR5 因子的表达.按条件培养基的不同将Saos-2 细胞分为4 组:含10% 胎牛血清的α-MEM 培养基(阴性对照)、Saos-2-CM(阳性对照)、MSC-CM、含24 ng/ml 兔抗人CCL5 抗体的MSC-CM(MSC-CM/anti-CCL5 Ab),应用Transwell实验和噻唑蓝(MTT)法分别检测hMSC 对Saos-2 细胞迁移与增殖能力的影响.实验均重复3 次.结果 免疫荧光细胞化学方法 和双抗体夹心ELISA 检测显示,hMSC CCL5 因子表达阳性且其表达水平为3.68 pg/ml.蛋白质免疫印迹检测显示,Saos-2 细胞CCR5因子表达阳性.Transwell 实验和MTT 检测结果 显示,MSC-CM 能明显促进Saos-2 细胞的迁移与增殖,而MSC-CM/anti- CCL5 Ab 组Saos-2 细胞的迁移与增殖能力均明显下降,2 组间差异均有统计学意义(分别为P < 0.01,P < 0.05).结论CCL5/CCR5 信号途径在hMSC 促进Saos-2 细胞迁移与增殖过程中发挥关键作用,抑制CCL5 趋化因子的表达可明显降低Saos-2 细胞的迁移与增殖能力.     

Expression and role of CCR6/CCL20 chemokine axis in pulmonary sarcoidosis

We have shown previously that the chemokine receptors CXCR3 and CXCR6 are coexpressed by Th1 cells infiltrating the lung and the granuloma of patients with sarcoidosis. In this study, we evaluated the role of CCL20/CCR6 interaction in the pathogenesis of acute and chronic pulmonary sarcoidosis. By flow cytometry and molecular analyses, we have demonstrated that Th1 cells isolated from the bronchoalveolar lavage (BAL) of patients with sarcoidosis and T cell alveolitis are equipped with CCR6. Furthermore, CCR6(+) T cells coexpressed the chemokine receptors CXCR3 and CXCR6. Immunohistochemical analysis of lung specimens has shown that CCR6(+) T cells infiltrate lung interstitium and surround the central core of the granuloma. It is interesting that CCR6 was never detected on the alveolar macrophage (AM) surface, and it is observed in the cytoplasm of AMs from patients with sarcoidosis and alveolitis. The CCR6 ligand CCL20 was expressed by macrophages, multinucleated giant cells, and epithelioid cells infiltrating the granuloma. Furthermore, detectable levels of CCL20 protein are seen in the BAL fluid components of patients with active sarcoidosis, and sarcoid AMs release the CCR6 ligand in vitro. From a functional point of view, sarcoid Th1 cells were able to respond to CXCL10, CXCL16, and CCL20 in migratory assays. In vitro kinetic studies demonstrated that CCR6 is induced rapidly by IL-2, IL-18, and IFN-gamma. In conclusion, T cells expressing CCR6, CXCR3, and CXCR6 act coordinately with respective ligands and Th1 inflammatory cytokines in the alveolitic/granuloma phases of the disease.     

Involvement of the MAPK and RhoA/ROCK pathways in PGE2-mediated CCR7-dependent monocyte migration

Prostaglandin E(2) (PGE(2)) induces the expression of C-C chemokine receptor type 7 (CCR7) on human monocytes, thereby enabling their subsequent migration in response to CCL19 and CCL21, the natural ligands for CCR7. To date, important mediators of PGE(2)-mediated monocyte migration remain unknown. In this study, we explored the role of mitogen-activated protein kinases and the RhoA/Rho-associated protein kinase (ROCK) pathway in CCR7-dependent monocyte migration in the presence of PGE(2). Our results indicate that CCL19 binding to CCR7 promotes the activation of p38, extracellular signal-regulated kinase 1/2, and c-Jun N-terminal kinase and leads to monocyte migration. Moreover, the RhoA/ROCK pathway was essential for PGE(2)-mediated CCR7-dependent monocyte migration.     

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 CCL2-based fusokine as a novel biopharmaceutical for the treatment of CCR2-driven autoimmune diseases

Autoimmune diseases represent one of the most challenging clinical entities with unmet medical needs, so the continued development of novel therapeutics is well justified. Most autoimmune diseases are marked by the infiltration of lymphomyeloid cells in target tissues, leading to inflammation and tissue damage. This process is guided by chemokines that act as signaling bridges amidst a complex network of immune cells. For example, monocytes are believed to be the primary cell type responsible for pathology initiation and tissue damage, while T lymphocytes are thought to orchestrate the process by secreting more cytokines/chemokines to amplify leukocyte homing. Many studies have addressed the molecular basis of monocyte recruitment in different autoimmune diseases, and the conclusions pointed to a major role played by monocyte chemoattractant protein 1 (MCP-1), also known as CC chemokine ligand 2 (CCL2), and its cell-surface receptor, CC chemokine receptor (CCR) 2. These findings suggest that by interfering with CCL2 or its receptor, it is possible to inhibit the progression of CCR2-dependent diseases. Therefore, future therapy design targeting a maladapted immune response could target chemokine receptors starting with the CCL2-CCR2 axis.     

依那西普缓解腰椎间盘突出模型大鼠的痛觉过敏并减少趋化因子CCL2和受体的表达

目的观察鞘内注射肿瘤坏死因子(TNF-α)抑制剂依那西普(etanercept)对腰椎间盘突出模型大鼠痛觉过敏的影响及背根神经节(DRG)和脊髓中趋化因子CCL2和其受体CCR2的表达变化。方法将大鼠随机分为:正常组(control组);假手术组(sham组)、自身髓核植入组(NP组)、NP+vehicle(vehicle组)、NP+etanercept(10μg)(10μg组)和NP+etanercept(100μg)(100μg组)。测定术前1 d及术后不同时间点左后爪机械性缩爪阈值(MWT)。实时荧光定量PCR法检测TNF-α、CCL2/CCR2 mRNA表达;免疫组化检测DRG中ED-1和ATF3的表达。结果 1)与sham组相比,NP组MWT在术后1 d明显降低(P0.001),持续21 d以上(P0.001);2)鞘内注射依那西普(100μg),在2,3,4 d都能缓解NP诱导的机械触痛觉过敏(P0.001);3)术前鞘内注射依那西普(100μg),抑制了DRG和脊髓中CCL2和CCR2 mRNA的上调。结论鞘内注射依那西普能抑制自体髓核移植所致的神经病理性疼痛,其机制可能与抑制CCL2/CCR2的上调有关。     

CCL2/CCR2 and CX3CL1/CX3CR1 chemokine axes and their possible involvement in age-related macular degeneration

The causes of age-related macular degeneration (AMD) are not well understood. Due to demographic shifts in the industrialized world a growing number of people will develop AMD in the coming decades. To develop treatments it is essential to characterize the disease's pathogenic process. Over the past few years, numerous studies have focused on the role of chemotactic cytokines, also known as chemokines. Certain chemokines, such as CCL2 and CX3CL1, appear to be crucial in subretinal microglia and macrophage accumulation observed in AMD, and participate in the development of retinal degeneration as well as in choroidal neovascularization. This paper reviews the possible implications of CCL2 and CX3CL1 signaling in AMD. Expression patterns, single nucleotide polymorphisms (SNPs) association studies, chemokine and chemokine receptor knockout models are discussed. Future AMD treatments could target chemokines and/or their receptors.     

Dual Role of CCR2 in the Constitution and the Resolution of Liver Fibrosis in Mice

Inflammation has been shown to induce the progression of fibrosis in response to liver injury. Among inflammatory cells, macrophages and lymphocytes play major roles in both the constitution and resolution of liver fibrosis. The chemokine receptor CCR2 is involved in the recruitment of monocytes to injury sites, and it is known to be induced during the progression of fibrosis in humans. However, its specific role during this process has not yet been unveiled. We first demonstrated that, compared with wild-type mice, CCR2 knockout animals presented a delay in liver injury after acute CCl₄ injection, accompanied by a reduction in infiltrating macrophage populations. We then induced fibrosis using repeated injections of CCl₄ and observed a significantly lower level of fibrotic scars at the peak of fibrosis in mutant animals compared with control mice. This diminished fibrosis was associated with a reduction in F4/80⁺CD11b⁺ and CD11c⁺ populations at the sites of injury. Subsequent analysis of the kinetics of the resolution of fibrosis showed that fibrosis rapidly regressed in wild-type, but not in CCR2^−/− mice. The persistence of hepatic injury in mutant animals was correlated with sustained tissue inhibitor of metalloproteinase-1 mRNA expression levels and a reduction in matrix metalloproteinase-2 and matrix metalloproteinase-13 expression levels. In conclusion, these findings underline the role of the CCR2 signaling pathway in both the constitution and resolution of liver fibrotic scars.Liver fibrosis and its progression toward cirrhosis is the consequence of chronic liver aggressions provoked by various agents such as viruses, bile acids, or alcohol. It is characterized by an accumulation of extracellular matrix mainly secreted by activated myofibroblasts and hepatic stellate cells (HSCs).^1,2 Although originally considered as an irreversible process, cirrhosis has now been shown to be potentially reversible, provided that the causative agent is removed.³ Current evidence suggests that the process of hepatic fibrosis is driven primarily by the development of an inflammatory reaction in response to parenchymal injury. In agreement with this hypothesis, deletion of specific components of the inflammatory response modifies or attenuates the fibrotic scar in vivo. It has been demonstrated that Kupffer cell inactivation,⁴ B lymphocyte deficiency,⁵ or macrophage depletion⁶ result in lower scarring and reduced activation of HSCs.Molecular mechanisms responsible for reversibility of liver fibrosis are only now starting to be deciphered. Experimental depletion of macrophages at the onset of fibrosis resolution retards extracellular matrix degradation and the loss of activated hepatic stellate cells.⁶ Therefore, macrophages seem to be crucial in both processes: fibrogenesis and fibrosis resolution.Chemokines are known to be critical mediators of inflammatory cell trafficking into sites of injury. Monocyte chemoattractant proteins (MCPs) attract cells through activation of their cognate receptor. MCP-1 is expressed by hepatocytes, endothelial cells, Kupffer cells, and HSCs in response to injury. CC chemokine receptor 2 (CCR2), which is expressed on monocytes/macrophages and on a subpopulation of T lymphocytes, has been found progressively up-regulated during the progression of liver fibrosis in humans.⁷ Moreover, comparison of serial sections of liver biopsies from patients with various degrees of necroinflammatory activity showed that infiltration with monocytes/macrophages is directly correlated with the expression of MCP-1,⁸ for which CCR2 is the main receptor.We hypothesized that signaling through CCR2 is involved in inflammatory cell recruitment during fibrogenesis and/or regression of fibrosis. To test this hypothesis, we compared the establishment and resolution of fibrosis after chronic liver aggression in CCR2-deficient mice versus wild-type mice. Our data show that the absence of CCR2 has opposite consequences during the constitution and the resolution of fibrosis.     

Genetic variation at the chemokine receptors CCR5/CCR2 in myocardial infarction

Our objective was to examine the association between myocardial infarction (MI) and two DNA-polymorphisms at the proinflammatory chemokine receptors CCR2 (I64V) and CCR5 (32 bp deletion, (Delta)ccr5), defining if these polymorphisms influence the age for the onset of MI. A total of 214 patients with an age at the first MI episode <55 years, 96 patients that suffered the first MI episode when older than 60 years, and 360 population controls were polymerase chain reaction genotyped for the CCR2-V64I and CCR5-Delta32/wt polymorphisms. Patients and controls were male from the same Caucasian population (Asturias, northern Spain). The frequency of the Deltaccr5 allele was significantly higher in controls compared to patients <55 years (P = 0.004), or in patients >60 years compared to patients <55 years (P = 0.002). Taking the patients >60 years as the reference group, non-carriers of the (Delta)ccr5-allele would have a three-fold higher risk of suffering an episode of MI at <55 years of age (OR = 3.06; 95% CI = 1.46-6.42). Gene and genotype frequencies for the CCR2 polymorphism did not differ between patients <55 years and controls or patients >60 years. Our data suggest that the variation at the CCR5 gene could modulate the age at the onset of MI. Patients carrying the (Delta)ccr5-allele would be protected against an early episode of MI. CCR5 and the CCR5-ligands are expressed by cells in the arteriosclerotic plaque. Thus, the protective role of (Delta)ccr5 could be a consequence of an attenuated inflammatory response, that would determine a slower progression of the arteriosclerotic lesion among (Delta)ccr5-carriers. Our work suggests that the pharmacological blockade of CCR5 could be a valuable therapy in the treatment of MI.