Monitoring and Cell-Specific Deletion of C5aR1 Using a Novel Floxed GFP-C5aR1 Reporter Knock-in Mouse
Monitoring and Cell-Specific Deletion of C5aR1 Using a Novel Floxed GFP-C5aR1 Reporter Knock-in Mouse
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DOI：
10.4049/jimmunol.1401401
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发表时间：
2015-02-15
影响因子：
4.4
通讯作者：
Koehl, Joerg
中科院分区：
文献类型：
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作者：
Karsten, Christian M.;Laumonnier, Yves;Koehl, Joerg
C5a的许多生物学特性是通过激活其受体(C5aR1)来实现的，其在中性粒细胞、单核细胞和巨噬细胞等髓系细胞上的表达已被证明是令人信服的。相反，关于C5aR1在树突状细胞(DC)和淋巴系细胞中的表达存在相互矛盾的结果。本文报道了一种绿色荧光蛋白C5aR1报告基因敲入小鼠的产生。使用该小鼠品系，我们证实了C5aR1在骨髓、血液、肺和脾中的中性粒细胞以及在腹膜巨噬细胞中有强烈的表达。此外，我们发现C5aR1在肺嗜酸性粒细胞、肺固有层和肺泡巨噬细胞、骨髓来源的DC、肺来源的CD11b(+)和单核细胞来源的DC中表达，而肠道和肺CD103(+)树突状细胞染色为阴性。部分脾NKT细胞表达GFP，而幼稚NK细胞和B2细胞缺乏GFP表达。最后，在体外和体内，我们没有观察到任何C5aR1在初始或激活的CD4(+)Th细胞中的表达。将GFP-C5aR1小鼠品系与LysMCre小鼠配对，我们能够特异性地删除中性粒细胞和巨噬细胞中的C5aR1，而C5aR1在DC中的表达保持不变。综上所述，我们的发现表明，C5aR1在小鼠中的表达在很大程度上限于髓系细胞。这种新型的C5aR1报告敲入小鼠将被证明有助于跟踪C5aR1在急性和慢性炎症实验模型中的表达，并有条件地删除免疫细胞中的C5aR1。
Many of the biological properties of C5a are mediated through activation of its receptor (C5aR1), the expression of which has been demonstrated convincingly on myeloid cells, such as neutrophils, monocytes, and macrophages. In contrast, conflicting results exist regarding C5aR1 expression in dendritic cells (DCs) and lymphoid lineage cells. In this article, we report the generation of a floxed GFP-C5aR1 reporter knock-in mouse. Using this mouse strain, we confirmed strong C5aR1 expression in neutrophils from bone marrow, blood, lung, and spleen, as well as in peritoneal macrophages. Further, we show C5aR1 expression in lung eosinophils, lung- and lamina propria-resident and alveolar macrophages, bone marrow-derived DCs, and lung-resident CD11b(+) and monocyte-derived DCs, whereas intestinal and pulmonary CD103(+) DCs stained negative. Also, some splenic NKT cells expressed GFP, whereas naive NK cells and B2 cells lacked GFP expression. Finally, we did not observe any C5aR1 expression in naive or activated CD4(+) Th cells in vitro or in vivo. Mating the floxed GFP-C5aR1 mouse strain with LysMCre mice, we were able to specifically delete C5aR1 in neutrophils and macrophages, whereas C5aR1 expression was retained in DCs. In summary, our findings suggest that C5aR1 expression in mice is largely restricted to cells of the myeloid lineage. The novel floxed C5aR1 reporter knock-in mouse will prove useful to track C5aR1 expression in experimental models of acute and chronic inflammation and to conditionally delete C5aR1 in immune cells.