Zarbock Alexander, Lowell Clifford A, Ley Klaus
Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA.
Immunity. 2007 Jun;26(6):773-83. doi: 10.1016/j.immuni.2007.04.011. Epub 2007 May 31.
Engagement of neutrophils by E-selectin results in integrin activation. Here, we investigated primary mouse neutrophils in whole blood by using intravital microscopy and autoperfused flow chambers. Slow rolling on E-selectin coimmobilized with intercellular adhesion molecule-1 (ICAM-1) required P-selectin glycoprotein ligand (PSGL)-1, was dependent on alpha(L)beta(2) integrin (LFA-1), and required continuous E-selectin engagement. Slow rolling was abolished by pharmacological blockade of spleen tyrosine kinase (Syk) and was absent in Syk(-/-) bone-marrow chimeric mice. Treatment with tumor necrosis factor-alpha lowered rolling velocity further and induced CXC chemokine ligand-1 (CXCL1) and CXC chemokine receptor-2 (CXCR2)-dependent leukocyte arrest on E-selectin and ICAM-1. Arrest but not rolling was blocked by an allosteric inhibitor of LFA-1 activation. Neutrophil recruitment in a thioglycollate-induced peritonitis model was almost completely inhibited in Selplg(-/-) mice or Syk(-/-) bone-marrow chimeras treated with pertussis toxin. This identifies a second neutrophil-activation pathway that is as important as activation through G protein-coupled receptors (GPCRs).
E-选择素与中性粒细胞的结合会导致整合素激活。在此，我们通过活体显微镜检查和自灌注流动腔室研究了全血中的原代小鼠中性粒细胞。在与细胞间黏附分子-1（ICAM-1）共固定的E-选择素上缓慢滚动需要P-选择素糖蛋白配体（PSGL）-1，依赖于α(L)β(2)整合素（淋巴细胞功能相关抗原-1，LFA-1），并且需要持续的E-选择素结合。脾酪氨酸激酶（Syk）的药理学阻断消除了缓慢滚动，并且在Syk基因敲除（Syk(-/-)）骨髓嵌合小鼠中不存在缓慢滚动现象。用肿瘤坏死因子-α处理可进一步降低滚动速度，并诱导CXC趋化因子配体-1（CXCL1）和CXC趋化因子受体-2（CXCR2）依赖性白细胞在E-选择素和ICAM-1上的停滞。LFA-1激活的变构抑制剂可阻断停滞但不能阻断滚动。在注射巯基乙酸诱导的腹膜炎模型中，Selplg基因敲除（Selplg(-/-)）小鼠或用百日咳毒素处理的Syk(-/-)骨髓嵌合体中的中性粒细胞募集几乎完全受到抑制。这确定了第二条中性粒细胞激活途径，其与通过G蛋白偶联受体（GPCRs）激活同样重要。
