Øynebråten Inger, Barois Nicolas, Bergeland Trygve, Küchler Axel M, Bakke Oddmund, Haraldsen Guttorm
1] Department of Pathology, Oslo University Hospital and University of Oslo, PO Box 4950 Nydalen, N-0424 Oslo, Norway [2] Centre for Immune Regulation, University of Oslo, RikshospitaletPO Box 4950 Nydalen, N-0424 Oslo, Norway.
The Department of Biosciences, University of Oslo, PO Box 1041 Blindern, 0316 N-Oslo, Norway.
Sci Rep. 2015 Mar 20;5:9261. doi: 10.1038/srep09261.
Vascular endothelial cells present luminal chemokines that arrest rolling leukocytes by activating integrins. It appears that several chemokines must form higher-order oligomers to elicit proper in vivo effects, as mutants restricted to forming dimers have lost the ability to recruit leukocytes to sites of inflammation. Here, we show for the first time that the chemokine RANTES/CCL5 binds to the surface of human endothelial cells in a regular filamentous pattern. Furthermore, the filaments bound to the surface in a heparan sulfate-dependent manner. By electron microscopy we observed labeling for RANTES on membrane projections as well as on the remaining plasma membrane. Mutant constructs of RANTES restricted either in binding to heparin, or in forming dimers or tetramers, appeared either in a granular, non-filamentous pattern or were not detectable on the cell surface. The RANTES filaments were also present after exposure to flow, suggesting that they can be present in vivo. Taken together with the lacking in vivo or in vitro effects of RANTES mutants, we suggest that the filamentous structures of RANTES may be of physiological importance in leukocyte recruitment.
血管内皮细胞呈现腔内趋化因子，这些趋化因子通过激活整合素来阻止滚动的白细胞。似乎几种趋化因子必须形成高阶寡聚体才能引发适当的体内效应，因为限于形成二聚体的突变体已失去将白细胞募集到炎症部位的能力。在这里，我们首次表明趋化因子RANTES/CCL5以规则的丝状模式结合到人类内皮细胞表面。此外，这些细丝以硫酸乙酰肝素依赖的方式结合到表面。通过电子显微镜，我们观察到RANTES在膜突起以及其余质膜上的标记。限制与肝素结合、或形成二聚体或四聚体的RANTES突变体构建体，要么呈现颗粒状、非丝状模式，要么在细胞表面无法检测到。在暴露于流动后，RANTES细丝也存在，这表明它们可能存在于体内。结合RANTES突变体在体内或体外缺乏效应的情况，我们认为RANTES的丝状结构在白细胞募集中可能具有生理重要性。
