Martin Clémence, Ohayon Delphine, Alkan Manal, Mocek Julie, Pederzoli-Ribeil Magali, Candalh Céline, Thevenot Guiti, Millet Arnaud, Tamassia Nicola, Cassatella Marco A, Thieblemont Nathalie, Burgel Pierre-Régis, Witko-Sarsat Véronique
1 Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
2 Department of Pneumology, Cochin Hospital, France.
Am J Respir Cell Mol Biol. 2016 May;54(5):740-50. doi: 10.1165/rcmb.2015-0047OC.
Neutrophil-associated inflammation during Pseudomonas aeruginosa lung infection is a determinant of morbidity in cystic fibrosis (CF). Neutrophil apoptosis is a key factor in inflammation resolution and is controlled by cytosolic proliferating cell nuclear antigen (PCNA). p21/Waf1, a cyclin-dependent kinase inhibitor, is a partner of PCNA, and its mRNA is up-regulated in human neutrophils during LPS challenge. We show here that, after 7 days of persistent infection with P. aeruginosa, neutrophilic inflammation was more prominent in p21(-/-) compared with wild-type (WT) mice. Notably, no intrinsic defect in the phagocytosis of apoptotic cells by macrophages was found in p21(-/-) compared with WT mice. Inflammatory cell analysis in peritoneal lavages after zymosan-induced peritonitis showed a significantly increased number of neutrophils at 48 hours in p21(-/-) compared with WT mice. In vitro analysis was consistent with delayed neutrophil apoptosis in p21(-/-) compared with WT mice. Ectopic expression of p21/waf1 in neutrophil-differentiated PLB985 cells potentiated apoptosis and reversed the prosurvival effect of PCNA. In human neutrophils, p21 messenger RNA was induced by TNF-α, granulocyte colony-stimulating factor, and LPS. Neutrophils isolated from patients with CF showed enhanced survival, which was reduced after treatment with a carboxy-peptide derived from the sequence of p21/waf1. Notably, p21/waf1 was detected by immunohistochemistry in neutrophils within lungs from patients with CF. Our data reveal a novel role for p21/waf1 in the resolution of inflammation via its ability to control neutrophil apoptosis. This mechanism may be relevant in the neutrophil-dominated inflammation observed in CF and other chronic inflammatory lung conditions.
铜绿假单胞菌肺部感染期间的中性粒细胞相关炎症是囊性纤维化（CF）发病的一个决定因素。中性粒细胞凋亡是炎症消退的关键因素，受胞质增殖细胞核抗原（PCNA）控制。p21/Waf1是一种细胞周期蛋白依赖性激酶抑制剂，是PCNA的伙伴，其mRNA在人中性粒细胞受到LPS刺激时上调。我们在此表明，在持续感染铜绿假单胞菌7天后，与野生型（WT）小鼠相比，p21基因敲除小鼠的嗜中性粒细胞炎症更为突出。值得注意的是，与WT小鼠相比，在p21基因敲除小鼠中未发现巨噬细胞吞噬凋亡细胞存在内在缺陷。在酵母聚糖诱导的腹膜炎后进行的腹腔灌洗中的炎性细胞分析显示，与WT小鼠相比，p21基因敲除小鼠在48小时时中性粒细胞数量显著增加。体外分析结果与p21基因敲除小鼠中性粒细胞凋亡延迟一致。在中性粒细胞分化的PLB985细胞中异位表达p21/waf1可增强凋亡并逆转PCNA的促生存作用。在人中性粒细胞中，p21信使RNA由TNF-α、粒细胞集落刺激因子和LPS诱导。从CF患者分离的中性粒细胞显示存活增强，在用源自p21/waf1序列的羧基肽处理后存活率降低。值得注意的是，通过免疫组织化学在CF患者肺部的中性粒细胞中检测到了p21/waf1。我们的数据揭示了p21/waf1通过控制中性粒细胞凋亡在炎症消退中的新作用。这种机制可能与CF和其他慢性炎症性肺部疾病中观察到的以中性粒细胞为主的炎症有关。
