Increased severity of glomerulonephritis in C-C chemokine receptor 2 knockout mice
Increased severity of glomerulonephritis in C-C chemokine receptor 2 knockout mice
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DOI：
10.1046/j.1523-1755.2000.00848.x
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发表时间：
2000-01-01
影响因子：
19.6
通讯作者：
Durham, SK
中科院分区：
文献类型：
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作者：
Bird, JE;Giancarli, MR;Durham, SK
C-C趋化因子受体2（CCR2）表达于单核细胞上，促进单核细胞迁移。CCR2是单核细胞趋化蛋白-1（MCP-1）的主要受体。这种趋化因子将单核细胞募集到炎症部位。研究表明，CCR2及其配体MCP-1在肾小球肾炎的发病机制中起作用。本研究的目的是确定CCR2在加速性肾毒性肾炎小鼠模型中的作用。我们测量了CCR2野生型和基因敲除小鼠在给予抗肾小球基底膜抗体后肾脏疾病的发展程度。对8组动物进行治疗（每组N = 10）。IgG免疫后4天，CCR2野生型和敲除小鼠接受对照血清或肾毒性血清。在第1天和第3天测量尿蛋白/肌酐比值;在第4天和第7天收集血浆和肾脏。通过光学显微镜、免疫组织化学和免疫荧光对肾脏进行评价。通过组织分析确定小鼠的基因型。在第1天观察到CCR2敲除对尿蛋白/肌酐比的保护作用，因为该参数的值（35 +/-3.6）显著低于肾炎野生型小鼠（50 +/-6.8）。与溶剂处理的野生型动物相比，第1天肾炎野生型小鼠的蛋白尿显著增加（5 +/-1.0）。在第3天，未观察到CCR2敲除的改善作用;肾炎CCR2野生型（92 +/-11.2）和敲除小鼠（102 +/-9.2）中尿蛋白/肌酐比值的增加相似。在第4天和第7天评价疾病的血浆标志物。在这些时间点，CCR 2受体敲除对血浆尿素氮、肌酸酐、白蛋白或胆固醇水平没有有利影响。在第7天，肾病CCR2基因敲除小鼠的血尿素氮（248 +/-19.9 mg/dL）和血浆胆固醇高于接受肾毒性血清的野生型小鼠（142 +/-41.7 mg/dL）。在第4天（3.1 +/-0.3 vs. 2.0 +/-0.3）和第7天（3.6 +/-0.2 vs. 2.9 +/-0.3），肾炎CCR2敲除小鼠的组织学损伤比肾炎野生型小鼠更严重。0.3）。通过第4天的免疫组织化学分析，与肾炎野生型动物（3.9 +/-0.5）相比，肾炎CCR2敲除小鼠（2.1 +/-0.6）的肾小球中的mac-2阳性细胞（代表巨噬细胞）显著较少。通过间接免疫荧光法，在野生型和CCR2基因敲除的肾炎小鼠的肾小球中均存在中等程度的弥漫性线性IgG沉积。这些结果表明，我们的策略成功地减少了巨噬细胞浸润，但这种肾小球肾炎模型并不仅仅依赖于疾病进展的CCR 2的存在。在对蛋白尿有短暂的改善作用后，CCR2基因敲除导致肾炎小鼠更严重的损伤。这就提出了一个有趣的可能性，即CCR2基因产物改善了这种小鼠模型中的肾小球肾炎。虽然在趋化因子敲除小鼠中发生的效应不等同于长期使用趋化因子拮抗剂的预期效应，但本研究可能对考虑长期使用趋化因子拮抗剂治疗肾脏疾病具有意义。
Background The C-C chemokine receptor 2 (CCR2) is expressed on monocytes and facilitates monocyte migration. CCR2 is a prominent receptor for monocyte chemoattractant protein-1 (MCP-1). This chemokine recruits monocytes to sites of inflammation. It has been suggested that CCR2 and its ligand, MCP-1, play a role in the pathogenesis of glomerulonephritis. The goal of this study was to determine the contribution of CCR2 in a murine model of accelerated nephrotoxic nephritis. We measured the extent of development of renal disease in CCR2 wild-type and knockout mice after the administration of antiglomerular basement membrane antibody.Methods. Eight groups of animals were treated (N = 10 per group). Four days after IgG immunization, CCR2 wild-type and knockout mice received control serum or nephrotoxic serum. The urinary protein/creatinine ratio was measured on days 1 and 3; plasma and kidneys were collected on days 4 and 7. Kidneys were evaluated by light microscopy, immunohistochemistry, and immunofluorescence. The genotype of mice was confirmed by tissue analysis.Results. Protective effects of CCR2 knockout on the urinary protein/creatinine ratio were observed on day 1, as values for this parameter were significantly lower (35 +/- 3.6) than in nephritic wild-type mice (50 +/- 6.8). There was a marked increase in proteinuria in nephritic wild-type mice on day 1 compared with vehicle-treated, wild-type animals (5 +/- 1.0). On day 3, the ameliorative effects of CCR2 knockout were not observed; the increase in the urinary protein/creatinine ratio was similar in nephritic CCR2 wild-type (92 +/- 11.2) and knockout mice (102 +/- 9.2). Plasma markers of disease were evaluated on days 4 and 7. At these time points, there were no beneficial effects of CCR2 receptor knockout on plasma levels of urea nitrogen, creatinine, albumin, or cholesterol. On day 7, blood urea nitrogen (248 +/- 19.9 mg/dL) and plasma cholesterol were higher in nephritic CCR2 knockout mice than in wild-type mice (142 +/- 41.7 mg/dL) that received nephrotoxic serum. Histopathologic injury was more severe in nephritic CCR2 knockout mice than nephritic wild-type mice on day 4 (3.1 +/- 0.3 vs. 2.0 +/- 0.3) and day 7 (3.6 +/- 0.2 vs. 2.9 +/-. 0.3). By immunohistochemical analysis at day 4, there were significantly fewer mac-2-positive cells, representative of macrophages in the,glomeruli of nephritic CCR2 knockout (2.1 +/- 0.6) mice than nephritic wild-type (3.9 +/- 0.5) animals. By indirect immunofluorescence, there was a moderate, diffuse linear IgG deposition of equivalent severity present in glomeruli of both wild-type and CCR2 knockout nephritic mice.Conclusion. These results suggest that our strategy was successful in reducing macrophage infiltration, but this model of glomerulonephritis is not solely dependent on the presence of CCR2 for progression of disease. After a transient ameliorative effect on proteinuria, CCR2 knockout led to more severe injury in nephritic mice. This raises the intriguing possibility that a CCR2 gene product ameliorates glomerulonephritis in this murine model. Although effects that occur in chemokine knockout mice are not equivalent to those expected with prolonged use of a chemokine antagonist, this study may nevertheless have implications for consideration of long-term use of chemokine antagonists in renal disease.