Eltayeb Sana, Berg Anna-Lena, Lassmann Hans, Wallström Erik, Nilsson Maria, Olsson Tomas, Ericsson-Dahlstrand Anders, Sunnemark Dan
Department of Clinical Neuroscience, Center for Molecular Medicine, Neuroimmunology Unit, Karolinska Institute, Stockholm, Sweden.
J Neuroinflammation. 2007 May 7;4:14. doi: 10.1186/1742-2094-4-14.
The CC chemokine receptors CCR1, CCR2 and CCR5 are critical for the recruitment of mononuclear phagocytes to the central nervous system (CNS) in multiple sclerosis (MS) and other neuroinflammatory diseases. Mononuclear phagocytes are effector cells capable of phagocytosing myelin and damaging axons. In this study, we characterize the regional, temporal and cellular expression of CCR1, CCR2 and CCR5 mRNA in the spinal cord of rats with myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis (MOG-EAE). While resembling human MS, this animal model allows unique access to CNS-tissue from various time-points of relapsing neuroinflammation and from various lesional stages: early active, late active, and inactive completely demyelinated lesions.
The expression of CCR1, CCR2 and CCR5 mRNA was studied with in situ hybridization using radio labelled cRNA probes in combination with immunohistochemical staining for phenotypic cell markers. Spinal cord sections from healthy rats and rats with MOG-EAE (acute phase, remission phase, relapse phase) were analysed. In defined lesion stages, the number of cells expressing CCR1, CCR2 and CCR5 mRNA was determined. Data were statistically analysed by the nonparametric Mann-Whitney U test.
In MOG-EAE rats, extensive up-regulation of CCR1 and CCR5 mRNA, and moderate up-regulation of CCR2 mRNA, was found in the spinal cord during episodes of active inflammation and demyelination. Double staining with phenotypic cell markers identified the chemokine receptor mRNA-expressing cells as macrophages/microglia. Expression of all three receptors was substantially reduced during clinical remission, coinciding with diminished inflammation and demyelination in the spinal cord. Healthy control rats did not show any detectable expression of CCR1, CCR2 or CCR5 mRNA in the spinal cord.
Our results demonstrate that the acute and chronic-relapsing phases of MOG-EAE are associated with distinct expression of CCR1, CCR2, and CCR5 mRNA by cells of the macrophage/microglia lineage within the CNS lesions. These data support the notion that CCR1, CCR2 and CCR5 mediate recruitment of both infiltrating macrophages and resident microglia to sites of CNS inflammation. Detailed knowledge of expression patterns is crucial for the understanding of therapeutic modulation and the validation of CCR1, CCR2 and CCR5 as feasible targets for therapeutic intervention in MS.
CC趋化因子受体CCR1、CCR2和CCR5对于单核吞噬细胞在多发性硬化症（MS）和其他神经炎症性疾病中募集至中枢神经系统（CNS）至关重要。单核吞噬细胞是能够吞噬髓磷脂并损伤轴突的效应细胞。在本研究中，我们对髓鞘少突胶质细胞糖蛋白诱导的实验性自身免疫性脑脊髓炎（MOG-EAE）大鼠脊髓中CCR1、CCR2和CCR5 mRNA的区域、时间和细胞表达进行了表征。虽然该动物模型类似于人类MS，但它允许从复发性神经炎症的不同时间点以及不同病变阶段（早期活动期、晚期活动期和完全脱髓鞘的非活动期）独特地获取中枢神经系统组织。
使用放射性标记的cRNA探针通过原位杂交结合表型细胞标志物的免疫组织化学染色来研究CCR1、CCR2和CCR5 mRNA的表达。分析来自健康大鼠和MOG-EAE大鼠（急性期、缓解期、复发期）的脊髓切片。在确定的病变阶段，确定表达CCR1、CCR2和CCR5 mRNA的细胞数量。数据通过非参数曼-惠特尼U检验进行统计分析。
在MOG-EAE大鼠中，在活跃炎症和脱髓鞘发作期间，脊髓中CCR1和CCR5 mRNA广泛上调，CCR2 mRNA中度上调。用表型细胞标志物进行双重染色将表达趋化因子受体mRNA的细胞鉴定为巨噬细胞/小胶质细胞。在临床缓解期间，所有三种受体的表达均大幅降低，这与脊髓中炎症和脱髓鞘的减轻相一致。健康对照大鼠在脊髓中未显示出任何可检测到的CCR1、CCR2或CCR5 mRNA表达。
我们的结果表明，MOG-EAE的急性和慢性复发期与中枢神经系统病变内巨噬细胞/小胶质细胞谱系细胞中CCR1、CCR2和CCR5 mRNA的不同表达相关。这些数据支持CCR1、CCR2和CCR5介导浸润性巨噬细胞和常驻小胶质细胞募集至中枢神经系统炎症部位的观点。对表达模式的详细了解对于理解治疗调节以及验证CCR1、CCR2和CCR5作为MS治疗干预的可行靶点至关重要。
