To efficiently cross the endothelial barrier during inflammation, neutrophils first firmly adhere to the endothelial surface using the endothelial adhesion molecule ICAM-1. Upon actual transmigration, the release from ICAM-1 is required. While Integrin LFA1/Mac1 de-activation is one described mechanism that leads to this, direct cleavage of ICAM-1 from the endothelium represents a second option. We found that a disintegrin and metalloprotease 10 (ADAM10) cleaves the extracellular domain of ICAM-1 from the endothelial surface. Silencing or inhibiting endothelial ADAM10 impaired the efficiency of neutrophils to cross the endothelium, suggesting that neutrophils use endothelial ADAM10 to dissociate from ICAM-1. Indeed, when measuring transmigration kinetics, neutrophils took almost twice as much time to finish the diapedesis step when ADAM10 was silenced. Importantly, we found increased levels of ICAM-1 on the transmigrating neutrophils when crossing an endothelial monolayer where such increased levels were not detected when neutrophils crossed bare filters. Using ICAM-1-GFP-expressing endothelial cells, we show that ICAM-1 presence on the neutrophils can also occur by membrane transfer from the endothelium to the neutrophil. Based on these findings, we conclude that endothelial ADAM10 contributes in part to neutrophil transendothelial migration by cleaving ICAM-1, thereby supporting the release of neutrophils from the endothelium during the final diapedesis step.

中文翻译：

---

ADAM10 介导的 ICAM-1 裂解参与中性粒细胞跨内皮迁移

为了在炎症期间有效地穿过内皮屏障，中性粒细胞首先使用内皮粘附分子 ICAM-1 牢固地粘附在内皮表面。在实际穿越时，需要从 ICAM-1 中释放。虽然整合素 LFA1/Mac1 失活是一种已描述的导致这种情况的机制，但从内皮直接裂解 ICAM-1 代表了第二种选择。我们发现去整合素和金属蛋白酶 10 (ADAM10) 从内皮表面切割 ICAM-1 的细胞外结构域。沉默或抑制内皮 ADAM10 会削弱中性粒细胞穿过内皮的效率，这表明中性粒细胞利用内皮 ADAM10 与 ICAM-1 分离。事实上，在测量轮回动力学时，当 ADAM10 被沉默时，中性粒细胞几乎需要两倍的时间来完成血尿步骤。重要的是，我们发现当穿过内皮单层时，轮回中性粒细胞上的 ICAM-1 水平增加，而当中性粒细胞穿过裸过滤器时，没有检测到这种增加的水平。使用表达 ICAM-1-GFP 的内皮细胞，我们表明 ICAM-1 在中性粒细胞上的存在也可以通过从内皮到中性粒细胞的膜转移发生。基于这些发现，我们得出结论，内皮 ADAM10 通过裂解 ICAM-1 部分促进中性粒细胞跨内皮迁移，从而支持在最后的血细胞渗出步骤期间从内皮释放中性粒细胞。我们发现，当穿过内皮单层时，轮回中性粒细胞上的 ICAM-1 水平增加，而当中性粒细胞穿过裸过滤器时，没有检测到这种增加的水平。使用表达 ICAM-1-GFP 的内皮细胞，我们表明 ICAM-1 在中性粒细胞上的存在也可以通过从内皮到中性粒细胞的膜转移发生。基于这些发现，我们得出结论，内皮 ADAM10 通过裂解 ICAM-1 部分促进中性粒细胞跨内皮迁移，从而支持在最后的血细胞渗出步骤期间从内皮释放中性粒细胞。我们发现，当穿过内皮单层时，轮回中性粒细胞上的 ICAM-1 水平增加，而当中性粒细胞穿过裸过滤器时，没有检测到这种增加的水平。使用表达 ICAM-1-GFP 的内皮细胞，我们表明 ICAM-1 在中性粒细胞上的存在也可以通过从内皮到中性粒细胞的膜转移发生。基于这些发现，我们得出结论，内皮 ADAM10 通过裂解 ICAM-1 部分促进中性粒细胞跨内皮迁移，从而支持在最后的血细胞渗出步骤期间从内皮释放中性粒细胞。