Bai Ming, Grieshaber-Bouyer Ricardo, Wang Junxia, Schmider Angela B, Wilson Zachary S, Zeng Liling, Halyabar Olha, Godin Matthew D, Nguyen Hung N, Levescot Anaïs, Cunin Pierre, Lefort Craig T, Soberman Roy J, Nigrovic Peter A
Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA.
Division of Nephrology, Massachusetts General Hospital, Boston, MA.
Blood. 2017 Nov 9;130(19):2092-2100. doi: 10.1182/blood-2017-03-768507. Epub 2017 Aug 14.
CD177 is a glycosylphosphatidylinositol (GPI)-anchored protein expressed by a variable proportion of human neutrophils that mediates surface expression of the antineutrophil cytoplasmic antibody antigen proteinase 3. CD177 associates with β2 integrins and recognizes platelet endothelial cell adhesion molecule 1 (PECAM-1), suggesting a role in neutrophil migration. However, CD177 neutrophils exhibit no clear migratory advantage in vivo, despite interruption of in vitro transendothelial migration by CD177 ligation. We sought to understand this paradox. Using a PECAM-1-independent transwell system, we found that CD177 and CD177 neutrophils migrated comparably. CD177 ligation selectively impaired migration of CD177 neutrophils, an effect mediated through immobilization and cellular spreading on the transwell membrane. Correspondingly, CD177 ligation enhanced its interaction with β2 integrins, as revealed by fluorescence lifetime imaging microscopy, leading to integrin-mediated phosphorylation of Src and extracellular signal-regulated kinase (ERK). CD177-driven cell activation enhanced surface β2 integrin expression and affinity, impaired internalization of integrin attachments, and resulted in ERK-mediated attenuation of chemokine signaling. We conclude that CD177 signals in a β2 integrin-dependent manner to orchestrate a set of activation-mediated mechanisms that impair human neutrophil migration.
CD177是一种糖基磷脂酰肌醇（GPI）锚定蛋白，由可变比例的人类中性粒细胞表达，介导抗中性粒细胞胞浆抗体抗原蛋白酶3的表面表达。CD177与β2整合素相关联，并识别血小板内皮细胞黏附分子1（PECAM-1），提示其在中性粒细胞迁移中发挥作用。然而，尽管通过CD177连接可阻断体外跨内皮迁移，但CD177阳性中性粒细胞在体内并未表现出明显的迁移优势。我们试图理解这一矛盾现象。使用一种不依赖PECAM-1的Transwell系统，我们发现CD177阳性和阴性中性粒细胞的迁移情况相当。CD177连接选择性地损害了CD177阳性中性粒细胞的迁移，这一效应是通过在Transwell膜上的固定和细胞铺展介导的。相应地，荧光寿命成像显微镜显示，CD177连接增强了其与β2整合素的相互作用，导致整合素介导的Src和细胞外信号调节激酶（ERK）磷酸化。CD177驱动的细胞活化增强了表面β2整合素的表达和亲和力，损害了整合素附着的内化，并导致ERK介导的趋化因子信号减弱。我们得出结论，CD177以β2整合素依赖性方式发出信号，以协调一系列激活介导的机制，从而损害人类中性粒细胞的迁移。
