Mishra Amarjit, Guo Yujie, Zhang Li, More Sunil, Weng Tingting, Chintagari Narendranath Reddy, Huang Chaoqun, Liang Yurong, Pushparaj Samuel, Gou Deming, Breshears Melanie, Liu Lin
Lundberg-Kienlen Lung Biology and Toxicology Laboratory, Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078;
Lundberg-Kienlen Lung Biology and Toxicology Laboratory, Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078; Oklahoma Center for Respiratory and Infectious Diseases, Oklahoma State University, Stillwater, OK 74078;
J Immunol. 2016 Oct 1;197(7):2828-37. doi: 10.4049/jimmunol.1501041. Epub 2016 Aug 24.
Pulmonary neutrophils are the initial inflammatory cells that are recruited during lung injury and are crucial for innate immunity. However, pathological recruitment of neutrophils results in lung injury. The objective of this study is to determine whether the novel neutrophil chemoattractant, soluble VCAM-1 (sVCAM-1), recruits pathological levels of neutrophils to injury sites and amplifies lung inflammation during acute lung injury. The mice with P2X7 receptor deficiency, or treated with a P2X7 receptor inhibitor or anti-VCAM-1 Abs, were subjected to a clinically relevant two-hit LPS and mechanical ventilation-induced acute lung injury. Neutrophil infiltration and lung inflammation were measured. Neutrophil chemotactic activities were determined by a chemotaxis assay. VCAM-1 shedding and signaling pathways were assessed in isolated lung epithelial cells. Ab neutralization of sVCAM-1 or deficiency or antagonism of P2X7R reduced neutrophil infiltration and proinflammatory cytokine levels. The ligands for sVCAM-1 were increased during acute lung injury. sVCAM-1 had neutrophil chemotactic activities and activated alveolar macrophages. VCAM-1 is released into the alveolar airspace from alveolar epithelial type I cells through P2X7 receptor-mediated activation of the metalloproteinase ADAM-17. In conclusion, sVCAM-1 is a novel chemoattractant for neutrophils and an activator for alveolar macrophages. Targeting sVCAM-1 provides a therapeutic intervention that could block pathological neutrophil recruitment, without interfering with the physiological recruitment of neutrophils, thus avoiding the impairment of host defenses.
肺中性粒细胞是肺损伤时最初募集的炎症细胞,对固有免疫至关重要。然而,中性粒细胞的病理性募集会导致肺损伤。本研究的目的是确定新型中性粒细胞趋化因子可溶性血管细胞黏附分子-1(sVCAM-1)是否会将病理性水平的中性粒细胞募集到损伤部位,并在急性肺损伤期间加剧肺部炎症。对P2X7受体缺陷小鼠,或用P2X7受体抑制剂或抗VCAM-1抗体处理的小鼠,进行具有临床相关性的两次打击(脂多糖和机械通气)诱导的急性肺损伤。检测中性粒细胞浸润和肺部炎症情况。通过趋化试验测定中性粒细胞趋化活性。在分离的肺上皮细胞中评估VCAM-1的脱落和信号通路。sVCAM-1的抗体中和、P2X7R缺陷或拮抗作用均可减少中性粒细胞浸润和促炎细胞因子水平。急性肺损伤期间sVCAM-1的配体增加。sVCAM-1具有中性粒细胞趋化活性并激活肺泡巨噬细胞。VCAM-1通过P2X7受体介导的金属蛋白酶ADAM-17激活,从I型肺泡上皮细胞释放到肺泡腔中。总之,sVCAM-1是一种新型的中性粒细胞趋化因子和肺泡巨噬细胞激活剂。靶向sVCAM-1提供了一种治疗干预措施,可阻断病理性中性粒细胞募集,而不干扰中性粒细胞的生理性募集,从而避免宿主防御功能受损。