Conway Institute, School of Medicine and Medical Science, University College Dublin, Dublin, United Kingdom;
INSERM U773, Université Paris 7 Denis Diderot, Sorbonne Paris Cité, Laboratoire d'Excellence Inflamex, Paris, France; and.
Blood. 2014 Jun 5;123(23):3635-45. doi: 10.1182/blood-2014-02-557843. Epub 2014 Apr 29.
Neutrophil responses are central to host protection and inflammation. Neutrophil activation follows a 2-step process in which priming amplifies responses to activating stimuli. Priming is essential for life span extension, chemotaxis, and respiratory burst activity. Here we show that the cytoskeletal organizer RhoA suppresses neutrophil priming via formins. Premature granule exocytosis in Rho-deficient neutrophils activated numerous signaling pathways and amplified superoxide generation. Deletion of Rho altered front-to-back coordination by simultaneously increasing uropod elongation, leading edge formation, and random migration. Concomitant negative and positive regulation of β2 integrin-independent and β2 integrin-dependent migration, respectively, reveal Rho as a key decision point in the neutrophil response to discrete chemotactic agents. Although even restricted influx of Rho-deficient hyperactive neutrophils exacerbated lipopolysaccharide-mediated lung injury, deleting Rho in innate immune cells was highly protective in influenza A virus infection. Hence, Rho is a key regulator of disease progression by maintaining neutrophil quiescence and suppressing hyperresponsiveness.
中性粒细胞反应是宿主保护和炎症的核心。中性粒细胞的激活遵循两步过程,其中,引发可放大对激活刺激的反应。引发对于寿命延长、趋化性和呼吸爆发活性是必不可少的。在这里,我们表明细胞骨架组织者 RhoA 通过formin 抑制中性粒细胞的引发。Rho 缺陷中性粒细胞中的过早颗粒胞吐激活了许多信号通路,并放大了超氧化物的产生。Rho 的缺失通过同时增加尾足伸长、前缘形成和随机迁移来改变前后协调。β2 整合素非依赖性和 β2 整合素依赖性迁移的协同负调节和正调节分别揭示了 Rho 作为中性粒细胞对离散趋化因子反应的关键决策点。尽管 Rho 缺陷的过度活跃中性粒细胞的甚至受限流入加剧了脂多糖介导的肺损伤,但在流感病毒感染中,先天免疫细胞中删除 Rho 具有高度保护作用。因此,Rho 通过维持中性粒细胞静止和抑制高反应性来调节疾病进展。