CC趋化因子受体4及其抑制剂研究进展

CC趋化因子受体4（CCR4）是G蛋白偶联受体家族成员之一,由包含7次跨膜结构域的多肽链组成,表达于多种细胞或组织中。CCR4通过与其内源性配体CCL17、CCL22及CKLF1作用介导多种炎症反应,尤其在哮喘发生和发展的病理过程中起重要作用,因此可能是某些炎性疾病、特别是哮喘的潜在治疗靶点。本文对CCR4及其抑制剂的研究进展做一综述。     

异钩藤碱对哮喘小鼠气道炎症的影响

目的 探讨异钩藤碱（IRN）调节单核细胞趋化蛋白1(MCP-1)/CC趋化因子受体2(CCR2)信号通路对哮喘小鼠气道炎症的影响。方法 通过注射和吸入卵清蛋白的方法建立哮喘小鼠模型，将造模成功后的小鼠随机分为哮喘组、IRN低剂量组（IRN-L组，灌胃10 mg/kg IRN）、IRN高剂量组（IRN-H组，灌胃20 mg/kg IRN）、IRN-H+CCL2组[灌胃20 mg/kg IRN+腹腔注射7.5 ng CC趋化因子配体（CCL2）]、阳性对照组（腹腔注射2 mg/kg地塞米松），并以注射和吸入无菌磷酸盐缓冲液的小鼠为空白对照组，每组10只。各药物组小鼠每天给予相应药物1次，连续给药2周。检测各组小鼠气道高反应指标——呼吸间歇（Penh）值，血清中肿瘤坏死因子α(TNF-α)、白细胞介素13(IL-13)、IL-4水平，支气管肺泡灌洗液中嗜酸性粒细胞（EOS）、淋巴细胞（LYM）和中性粒细胞（NEU）数量，肺组织中MCP-1、CCR2蛋白表达水平；观察肺组织病理学变化并进行炎症细胞浸润评分。结果 与空白对照组比较，哮喘组小鼠肺组织炎症细胞浸润较明显，并有细胞肿胀、脱落现象发生；...     

CCR3的缺失导致阿尔茨海默病小鼠模型中β-淀粉样蛋白和过度磷酸化tau蛋白的减少

目的慢性神经炎症可能参与阿尔茨海默病(AD),其特征在于,神经胶质细胞活化和促炎性细胞因子和趋化因子的分泌。趋化因子CCL11已被证明是衰老过程中认知衰退的致病因素,但它是否参与AD的发病却很少被我们所知。在本研究中,我们拟在小鼠模型中回答CCL11及其受体CCR3是否参与AD发病过程的问题。方法我们采用了免疫组化、蛋白印迹和体视学细胞计数等方法来回答上述问题。结果 CCL11特异性受体CCR3的缺失使APP/PS1双转基因小鼠脑内tau蛋白磷酸化,Aβ沉积以及小胶质细胞及星形胶质细胞增生显著降低。结论 CCL11的增加可能是AD的危险因素,并且拮抗CCR3可能给AD带来治疗益处。     

风湿性二尖瓣狭窄瓣膜组织CCL19和CCR7的表达

目的研究趋化因子配体19(CCL19)及其受体趋化因子受体7(CCR7)在风湿性二尖瓣狭窄(RMS)患者瓣膜组织中的表达、分布特点和细胞定位。方法采用GeneChip Human Gene1.0ST基因芯片和免疫组织化学染色法检测RMS病变二尖瓣瓣膜(A组,16例)和正常瓣膜(B组,3例)中CCL19和CCR7的表达情况。结果 A组CCL19和CCR7均高表达;其中,CCL19主要分布在炎症细胞区域,CCR7主要在瓣膜间质细胞表达。而B组中CCL19和CCR7均无明显表达。结论 RMS患者二尖瓣瓣膜组织中CCL19主要表达于浸润的炎症细胞,CCR7表达于瓣膜间质细胞,两者相互作用参与瓣膜的病理过程。     

Analysis of CCL19 and CCR7 expressions in mitral valves in patients with rheumatic mitral stenosis

目的 研究趋化因子配体19(CCL19)及其受体趋化因子受体7(CCR7)在风湿性二尖瓣狭窄(RMS)患者瓣膜组织中的表达、分布特点和细胞定位.方法 采用GeneChip Human Gene 1.0 ST基因芯片和免疫组织化学染色法检测RMS病变二尖瓣瓣膜(A组,16例)和正常瓣膜(B组,3例)中CCL19和CCR7的表达情况.结果 A组CCL19和CCR7均高表达;其中,CCL19主要分布在炎症细胞区域,CCR7主要在瓣膜间质细胞表达.而B组中CCL19和CCR7均无明显表达.结论 RMS患者:尖瓣瓣膜组织中CCL19主要表达于浸润的炎症细胞,CCR7表达于瓣膜间质细胞,两者相互作用参与瓣膜的病理过程.     

MCP-1/CCR2信号轴与消化系统肿瘤发生发展的研究进展

单核细胞趋化蛋白1（MCP-1）/CC 趋化因子受体2（CCR2）信号轴是指由趋化因子MCP-1 与其特异性受体CCR2 相互作用构成的一个与细胞间信息传递和细胞迁移有密切关系的耦联分子对，在肿瘤细胞以及肿瘤微环境中的多种细胞中表达，对肿瘤的发生发展起重要作用。在消化系统肿瘤发生发展过程中，MCP-1/CCR2 信号轴的作用越来越受到国内外的关注，相关分子机制研究涉及肿瘤相关巨噬细胞的募集和极化，新生血管生成及异常免疫反应等，可为消化系统肿瘤防治提供新的思路。本文就近年来对MCP-1/CCR2 信号轴与消化系统肿瘤发生发展的研究进展进行综述。     

CCL20及其受体CCR6在非小细胞肺癌组织的表达及意义

<正>CCL20是近来发现的CC趋化因子家族的新成员,主要表达于肝脏、肺脏、淋巴结、胰腺及外周血细胞[1]。CCR6是CCL20的特异性趋化因子受体。目前关于CCL20及其受体CCR6的研究多集中在与乳腺癌、胰腺癌、肝癌的发生、转移的关系上,而与非小细胞肺癌相关的研究报道甚少。本文通过采用快捷免疫组织化学MaxVision两步法检测CCL20及其受体CCR6在肺癌组织、癌旁组织的表达,并以正常肺组     

新型P2Y样G蛋白偶联受体GPR17在脑缺血损伤中的作用

目的探讨新型P2Y样G蛋白偶联受体GPR17对脑缺血及缺氧缺糖(OGD)诱导皮层混合培养细胞中神经元损伤及小胶质细胞激活的影响。方法①以线栓法制备大鼠局灶性脑缺血模型,采用免疫组织化学、Western blotting、RT-PCR以及免疫荧光等方法观察脑内GPR17的时空表达及细胞分布特点。大鼠侧脑室埋管给予GPR17 siRNA靶向沉默脑内GPR17表达,观察其对脑缺血急、慢性期神经元损伤和小胶质细胞激活的影响。②以OGD诱导大鼠皮层混合培养细胞的缺血性损伤,以GPR17 siRNA靶向沉默GPR17的表达,观察其对OGD诱导的原代皮层混合培养细胞中神经元损伤和小胶质细胞激活的影响。结果①缺血中心区,GPR17 mRNA及蛋白水平在再灌注24 h和7,14 d表达上调;缺血周边区,再灌注7,14 d表达上调。在正常大鼠脑组织,GPR17主要表达于神经元、少突胶质细胞。在缺血中心区,再灌注24 h GPR17主要表达于损伤的神经元、小胶质细胞和少突胶质细胞,再灌注14 d主要表达于增生激活的小胶质细胞,部分表达于少突胶质细胞;而在缺血周边区,再灌注24 h以及14 d,GPR17主要表达于神经元、小胶质细胞和少突胶质细胞。星形胶质细胞不表达GPR17。大鼠侧脑室给予GPR17 siRNA成功抑制脑内GPR17表达,显著改善再灌注24 h神经症状、减少脑梗死体积以及神经元损伤;同样,也改善再灌注14 d的脑萎缩和周边区的神经元损伤,并显著抑制小胶质细胞的增生激活。②大鼠原代皮层混合培养细胞中,OGD 1 h恢复24 h(OGD/R)诱导细胞活性降低,LDH释放增加,PI染色结果显示细胞坏死增加,以神经元死亡为主。GPR17 siRNA处理后减轻OGD/R诱导的细胞活性下降以及LDH释放,并减轻细胞坏死,以减轻神经元死亡为主;GPR17siRNA处理后能够改善小胶质细胞激活的形态变化。结论大鼠局灶性脑缺血后,脑内GPR17表达上调,介导缺血后急性神经元损伤以及亚急性/慢性期的小胶质细胞激活。GPR17还介导OGD诱导的大鼠皮层混合培养细胞中的神经元损伤和小胶质细胞激活。     

丹酚酸A通过激活Nrf2抗氧化通路同时抑制MMP-9保护血脑屏障共同发挥抗脑缺血再灌注损伤作用

目的研究丹酚酸A减轻大鼠脑缺血再灌注损伤的机制。方法在整体动物水平建立大鼠脑缺血再灌注损伤模型,缺血1.5 h,再灌注24 h。结果丹酚酸A可以改善脑缺血再灌注导致的大鼠肢体偏瘫,降低神经行为学缺损评分,缩小脑梗死体积,降低脑水肿程度,改善病理损伤。并且,丹酚酸A能够减少受损脑组织中MDA水平,增加抗氧化酶SOD及GPx的活性,激活Nrf2/HO-1信号通路,促进Nrf2合成和核转位,进而促进抗氧化蛋白HO-1的表达,抑制缺血再灌注诱发的氧化应激。另外,丹酚酸A能够抑制受损脑区中小胶质细胞和星形胶质细胞的活化,下调脑内炎症因子TNF-α、IL-1β和IL-6的合成和分泌,降低受损脑区中IKK和IκBα的磷酸化水平,以及NF-κB的磷酸化程度,从而阻断NF-κB信号通路,抑制缺血再灌注引起的神经炎症。在血脑屏障保护方面,丹酚酸A能够通过减少受损脑区中MMP-9的表达和活化,抑制紧密连接蛋白ZO-1、Occludin和Claudin-5的降解,从而维持血脑屏障的完整性。结论丹酚酸A对脑缺血再灌注损伤大鼠具有明显的保护作用,一方面是通过激活PI3K/Akt/Nrf2/HO-1通路发挥抗氧化应激作用实现的;另一方面是通过抑制MMP-9活性,阻止MMP-9介导的紧密连接蛋白降解,抑制NF-κB活化,综合发挥抗脑缺血再灌注损伤作用。     

复方中药塞络通对多发性脑梗死大鼠星形胶质细胞功能及脂笼蛋白2蛋白表达的影响

目的脑卒中是一种常见的疾病,绝大多数脑卒中病例是由短暂性或永久性脑血管闭塞引起的缺血性脑血管病(缺血性中风)最终导致脑梗死。星形胶质细胞做为脑内大量存在的细胞,在缺血损伤后形态肥大,表现为突起延长和胞体肿胀。脂笼蛋白2(LCN2)是一种分泌蛋白,在脑缺血和神经退行性疾病中具有重要作用。塞络通胶囊(SLT)是由人参、银杏、藏红花三种中草药组成的治疗血管性痴呆的标准化制剂。虽然最近的临床试验已经证明SLT对血管性痴呆的有益作用,但其潜在的细胞机制尚未得到充分的探索。方法采用大鼠微球法致多发性脑梗死实验模型,通过Morris水迷宫实验评价SLT对恢复期大鼠空间记忆功能障碍的影响;随后,根据组织内及血清内炎性因子的表达,以及qPCR、免疫荧光、免疫印迹观察星形胶质细胞的活化、特异蛋白LCN2及其诱导的JAK2\STAT3信号通路的变化,以考察恢复期脑缺血损伤后星形胶质细胞的活化与炎性反应的关系及SLT对恢复期缺血损伤皮层区星形胶质细胞功能的影响;建立人星形胶质细胞糖氧诱导(OGD)损伤模型,并采用慢病毒转染的方法过表达目的基因LCN2,检测细胞分泌炎性因子含量变化,免疫荧光、蛋白免疫印迹观察星形胶质细胞的活化、特异蛋白LCN2及其诱导的JAK2/STAT3信号通路的变化,考察星形胶质细胞损伤后SLT有效成分对其的影响。结果 SLT可显著降低脑缺血引起的大鼠空间记忆认知功能障碍,减轻星形胶质细胞的活化及增殖,较为明显改善脑脑缺血损伤大鼠皮层缺血周边半暗带区神经元及突触超微结构损伤;SLT可抑制缺血侧皮层区及血清内炎性因子及趋化因子的表达,根据免疫荧光与免疫印迹的结果看出,SLT可能通过抑制LCN2诱导的JAK2/STAT3信号通路的表达来抑制炎性反应。结论 SLT介导神经炎症反应,通过LCN2-JAK2/STAT3通路抑制星形胶质细胞增生,抑制神经炎症反应,从而保护缺血性脑损伤,为缺血性脑卒中的治疗策略提供新的思路。     

Novel C-C chemokine receptor 2 antagonists in metabolic disease: a review of recent developments

Introduction: C-C chemokine ligand 2 (CCL2), also known as monocyte chemoattractant protein-1, and its receptor, C-C chemokine receptor 2 (CCR2), play important roles in various inflammatory diseases. Recently, it has been reported that the CCL2/CCR2 pathway also has an important role in the pathogenesis of metabolic syndrome through its association with obesity and related systemic complications.

Areas covered: This review focuses on the roles of CCR2 in the pathogenesis of adipose tissue inflammation and other organ damage associated with metabolic syndrome, which is still a matter of debate in many studies. It also covers the use of novel CCR2 antagonists as therapies in such conditions.

Expert opinion: There is abundant experimental evidence that the CCL2/CCR2 pathway may be involved in chronic low-grade inflammation of adipose tissue in obesity and related metabolic diseases. Although animal models of diabetes and obesity, as well as human trials, have produced controversial results, there is continued interest in the roles of CCR2 inhibition in metabolic disease. Further identification of the mechanisms for recruitment and activation of phagocytes and determination of the roles of other chemokines are needed. Future study of these fundamental questions will provide a clearer understanding of adipose tissue biology and potential therapeutic targets for treatment of obesity-related metabolic disease, including diabetic nephropathy.     

Novel C-C chemokine receptor 2 antagonists in metabolic disease: a review of recent developments

INTRODUCTION: C-C chemokine ligand 2 (CCL2), also known as monocyte chemoattractant protein-1, and its receptor, C-C chemokine receptor 2 (CCR2), play important roles in various inflammatory diseases. Recently, it has been reported that the CCL2/CCR2 pathway also has an important role in the pathogenesis of metabolic syndrome through its association with obesity and related systemic complications. AREAS COVERED: This review focuses on the roles of CCR2 in the pathogenesis of adipose tissue inflammation and other organ damage associated with metabolic syndrome, which is still a matter of debate in many studies. It also covers the use of novel CCR2 antagonists as therapies in such conditions. EXPERT OPINION: There is abundant experimental evidence that the CCL2/CCR2 pathway may be involved in chronic low-grade inflammation of adipose tissue in obesity and related metabolic diseases. Although animal models of diabetes and obesity, as well as human trials, have produced controversial results, there is continued interest in the roles of CCR2 inhibition in metabolic disease. Further identification of the mechanisms for recruitment and activation of phagocytes and determination of the roles of other chemokines are needed. Future study of these fundamental questions will provide a clearer understanding of adipose tissue biology and potential therapeutic targets for treatment of obesity-related metabolic disease, including diabetic nephropathy.     

CKLF1/CCR5 axis is involved in neutrophils migration of rats with transient cerebral ischemia

BackgroundChemokine-like factor 1 (CKLF1) is a chemokine increased significantly in ischemic brain poststroke. It shows chemotaxis effects on various immune cells, but the mechanisms of CKLF1 migrating neutrophils are poorly understood. Recent studies have provided evidence that CC chemokine receptor 5 (CCR5), a receptor of CKLF1, is involved in ischemic stroke.PurposesTo investigate the effects of HIF-1α guided AAV in ischemic brain, investigating the outcome of stroke, and examining the involvement of CKLF1/CCR5 axis in recruitment of neutrophils.ResultsHIF-1α guided AAV knocked down CKLF1 in ischemic area and alleviated brain damage of rats. CKLF1 migrated neutrophils through CCR5, worsening inflammatory responses. Akt/GSK-3β pathway may involve in CKLF1/CCR5 axis guided neutrophils chemotaxis.ConclusionsCKLF1/CCR5 axis is involved in neutrophils migration of rats with transient cerebral ischemia. CKLF1/CCR5 axis may be a useful target for stroke therapy.     

Functional analysis of chemically synthesized derivatives of the human CC chemokine CCL15/HCC‐2, a high affinity CCR1 ligand

Abstract: The CCL15 is a human CC chemokine that activates the receptors, CCR1 and CCR3. Unlike other chemokines, it contains an unusually long N‐terminal domain of 31 amino acids preceding the first cysteine residue and a third disulfide bond. To elucidate the functional role of distinct structural determinants, a series of sequential amino‐terminal truncated and point‐mutated CCL15 derivatives as well as mutants lacking the third disulfide bond and the carboxy‐terminal α‐helix were synthesized using 9‐fluorenylmethoxycarbonyl (Fmoc) chemistry. We demonstrate that a truncation of 24 amino acid residues (Δ24‐CCL15) converts the slightly active 92‐residue Δ0‐CCL15 into a potent agonist of CC chemokine receptor 1 (CCR1) and a weak agonist of CCR3 in cell‐based assays. The biological activity decreases from Δ24‐CCL15 to Δ29‐CCL15, and re‐increases from Δ29‐CCL15 to Δ30‐CCL15. Thus, an exocyclic N‐terminal region of only one amino acid residue is sufficient for efficient CCR1 activation. As none of the peptides investigated except for Δ24‐CCL15 activates CCR3, we suggest that CCR1 is the major receptor for CCL15 in vivo. Further we demonstrate that the third disulfide bond of CCL15 and an exchange of tyrosine in position 70 by a leucine residue, which is conserved in CXC chemokines, do not alter the interaction with CCR1. In contrast, a CCL15 derivative lacking the carboxy‐terminal α‐helix exhibits a complete loss of tertiary structure and hence loss of CCR1 agonistic and binding activity. This study demonstrates that specific protein residues in chemokines, which contribute to receptor–ligand interaction, vary significantly between chemokines and cannot be extrapolated using data from functionally related chemokines.     

Identification and characterization of a potent, selective nonpeptide agonist of the CC chemokine receptor CCR8

In this study, we report the first example of a nonpeptide chemokine receptor agonist, 2-{2-[4-(3-phenoxybenzyl)piperazin-1-yl]ethoxy}ethanol (ZK 756326), for the CC chemokine receptor CCR8. ZK 756326 inhibited the binding of the CCR8 ligand I-309 (CCL1), with an IC(50) value of 1.8 muM. Furthermore, ZK 756326 was a full agonist of CCR8, dose-responsively eliciting an increase in intracellular calcium and cross-desensitizing the response of the receptor to CCL1. In addition, ZK 756326 stimulated extracellular acidification in cells expressing human CCR8. The ability of ZK 756326 to induce a response was receptor-specific and mediated through Galpha(i), because it could be blocked by treatment with pertussis toxin. The CCR8 agonist activated cells expressing murine CCR8, eliciting their chemotaxis and inducing phosphorylation of extracellular signal-regulated kinase ERK1/2. Like CCL1, ZK 756326 inhibited human immunodeficiency virus (HIV) fusion of cells expressing CD4 and CCR8. Finally, unlike mCCL1, ZK 756326 bound to and activated a form of mCCR8 that was mutated to eliminate O-linked sulfation at tyrosines 14 and 15. Therefore, ZK 756326 is most probably not binding in the same manner as CCL1 but can activate the switch mechanism involved in transducing signaling events. In summary, we have identified a nonpeptide agonist of CCR8. This compound may be useful in evaluating the physiological role of CCR8 in HIV infection, as well as in the general study of CCR8 biology without the constraints inherent to the use of protein agonists such as its natural ligand.     

Analysis of second messenger pathways stimulated by different chemokines acting at the chemokine receptor CCR5

The chemokine receptor, CCR5, responds to several chemokines leading to changes in activity in several signalling pathways. Here, we investigated the ability of different chemokines to provide differential activation of pathways. The effects of five CC chemokines acting at CCR5 were investigated for their ability to inhibit forskolin-stimulated 3'-5'-cyclic adenosine monophosphate (cAMP) accumulation and to stimulate Ca(2+) mobilisation in Chinese hamster ovary (CHO) cells expressing CCR5. Macrophage inflammatory protein 1alpha (D26A) (MIP-1alpha (D26A), CCL3 (D26A)), regulated on activation, normal T-cell expressed and secreted (RANTES, CCL5), MIP-1beta (CCL4) and monocyte chemoattractant protein 2 (MCP-2, CCL8) were able to inhibit forskolin-stimulated cAMP accumulation, whilst MCP-4 (CCL13) could not elicit a response. CCL3 (D26A), CCL4, CCL5, CCL8 and CCL13 were able to stimulate Ca(2+) mobilisation through CCR5, although CCL3 (D26A) and CCL5 exhibited biphasic concentration-response curves. The Ca(2+) responses induced by CCL4, CCL5, CCL8 and CCL13 were abolished by pertussis toxin, whereas the response to CCL3 (D26A) was only partially inhibited by pertussis toxin, indicating G(i/o)-independent signalling induced by this chemokine. Although the rank order of potency of chemokines was similar between the two assays, certain chemokines displayed different pharmacological profiles in cAMP inhibition and Ca(2+) mobilisation assays. For instance, whilst CCL13 could not inhibit forskolin-stimulated cAMP accumulation, this chemokine was able to induce Ca(2+) mobilisation via CCR5. It is concluded that different chemokines acting at CCR5 can induce different pharmacological responses, which may account for the broad spectrum of chemokines that can act at CCR5.     

Chemokine CCL2 enhances NMDA receptor-mediated excitatory postsynaptic current in rat hippocampal slices-a potential mechanism for HIV-1-associated neuropathy?

Human immunodeficiency virus type 1 (HIV-1)-infected mononuclear phagocytes (brain macrophages and microglial cells) release proinflammatory cytokines and chemokines. Elevated levels of chemokine CC motif ligand 2 (CCL2, known previously as monocyte chemoattractant protein-1) have been detected in serum and cerebrospinal fluid (CSF) of HIV-1-infected individuals and the raised CCL2 in the CSF correlates with HIV-1-associated neurocognitive disorders. To understand how elevated CCL2 induces HIV-1-associated neuropathy, we studied effects of CCL2 on excitatory postsynaptic current (EPSCs) in the CA1 region of rat hippocampal brain slices using whole-cell patch recording techniques. The AMPA receptor (AMPAR)-mediated EPSC (EPSC_AMPAR) and N-Methyl-D-aspartate (NMDA) receptor (NMDAR)-mediated EPSCs (EPSC_NMDAR) were isolated pharmacologically. Bath application of CCL2 produced a significant enhancement of the amplitudes of EPSCs, EPSC_AMPAR and EPSC_NMDAR. Further studies revealed that CCL2 potentiated NMDAR subtype NR2A-mediated EPSC (EPSC_NR2AR) and NR2B-mediated EPSC (EPSC_NR2BR). To determine the site of action, we recorded spontaneous mini EPSCs (mEPSC) before and during bath application of CCL2. Our results showed that CCL2 decreased inter event interval (IEI) and increased the frequency of mEPSCs without change on the amplitude, suggesting a presynaptic site of CCL2 action. CCL2 was also found to injure primary rat hippocampal neuronal cultures and neuronal dendrites in the CA1 region of hippocampal slices. The CCL2-associated neuronal and dendritic injuries were blocked by a specific NMDAR antagonist or by a CCR2 receptor antagonist, indicating that CCL2-associated neural injury was mediated via NMDARs and/or CCR2 receptors. Taken together, these results suggest a potential role CCL2 may play in HIV-1-associated neuropathology.     

Investigational C-C chemokine receptor 2 antagonists for the treatment of autoimmune diseases

Background: C-C chemokine receptor 2 (CCR2) antagonists belong to a group of chemokine blockers, which represent a new strategy for inflammatory diseases treatment by interfering with the complex system of chemokines and their receptors. A number of CCR2 antagonists are being developed for treatment of autoimmune diseases by different pharmaceutical and biotechnological companies. Objective: In this article the dark and the bright side of therapeutic CCR2 antagonism is discussed, with a view to its potential efficacy in various autoimmune diseases, in which clinical trials are already in progress, such as multiple sclerosis and rheumatoid arthritis. We describe different modes of possible interactions with CCR2–chemokine CC motif ligand 2 (CCL2) axis, usefulness of experimental animal models, continuing clinical trials and future perspectives of CCR2 antagonists. Methods: Until now only a few peer-reviewed articles providing data on the progress of preclinical and clinical trials with CCR2 antagonists have been published; therefore, we also present data based on preliminary reports, obtained from a number of press releases, conference communications and from the PharmaProjects database. Results/Conclusion: Although there is growing evidence for a great therapeutic potential of CCR2 blockade in autoimmune diseases, especially well documented in experimental animal models, so far clinical trials with CCR2 antagonists in humans have been moderately encouraging or even disappointing, indicating a need to further elucidate the complex system of chemokine interactions.     

Cocaine-mediated Alteration in Tight Junction Protein Expression and Modulation of CCL2/CCR2 Axis Across the Blood-Brain Barrier: Implications for HIV-Dementia

One of the hallmark features underlying the pathogenesis of HIV encephalitis is the disruption of blood–brain barrier (BBB). Cocaine, often abused by HIV-infected patients, has been suggested to worsen the HIV-associated dementia (HAD) via unknown mechanisms. The objective of the present study was to explore the effects of cocaine on BBB permeability using human brain microvascular endothelial cells (HBMECs). Additionally, because the chemokine CCL2 and its receptor CCR2 play a crucial role in the recruitment of inflammatory cells into the central nervous system in HAD brains, we tested for the effect of cocaine in modulating the CCL2/CCR2 axis. Our findings suggest that exposure of HBMECs to cocaine correlated with the breakdown of ZO-1 tight junction protein and reorganization of the cytoskeleton resulting in stress fiber formation. Furthermore, cocaine also modulated upregulation of the CCL2/CCR2 axis in monocytes. These findings conform to the multifaceted effects of cocaine leading to accelerated progression of HIV-1 neuropathogenesis.     

Transgenic mouse expressing human CCR5 as a model for in vivo assessments of human selective CCR5 antagonists

The species selectivity of receptor antagonists often hinders their preclinical assessment in vivo. In order to evaluate human selective CC chemokine receptor type 5 (CCR5) antagonists in vivo, we generated human CCR5 transgenic mice that expressed the transgene on both peripheral blood leukocytes as well as thymocytes. The selective CCR5 ligand CC chemokine ligand 4 (CCL4)/macrophage inflammatory protein (MIP)-1beta induced the chemotaxis of thymocytes that had been derived from the transgenic mice, but not from littermate mice, suggesting that the human CCR5 expressed in the transgenic mice were functional. The binding of the human CCR5 specific antibody 45531 to peripheral blood granulocytes from the transgenic mice was inhibited by human selective CCR5 antagonist SCH-351125. Using this antibody, we developed an ex vivo assay system that is suitable for the evaluation of a test compound's ability to occupy the human CCR5 receptor on mouse peripheral blood leukocytes. This transgenic mouse model is useful for estimating the pharmacodynamics of human selective CCR5 antagonists in vivo.