| First Author | Martin C | Year | 2016 |
| Journal | Am J Respir Cell Mol Biol | Volume | 54 |
| Issue | 5 | Pages | 740-50 |
| PubMed ID | 26517580 | Mgi Jnum | J:251349 |
| Mgi Id | MGI:6101361 | Doi | 10.1165/rcmb.2015-0047OC |
| Citation | Martin C, et al. (2016) Neutrophil-Expressed p21/waf1 Favors Inflammation Resolution in Pseudomonas aeruginosa Infection. Am J Respir Cell Mol Biol 54(5):740-50 |
| abstractText | 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-alpha, 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. |
