title: Modulation of phagocytosis of apoptotic neutrophils by supernatant from dexamethasone-treated macrophages and annexin-derived peptide Ac(2-26).
abstract: Phagocytic clearance of apoptotic leukocytes plays an important role in the resolution of inflammation. The glucocorticoid-inducible protein annexin 1 and annexin 1-derived peptides show potent anti-inflammatory responses in acute and chronic inflammation. In this study, we report that the annexin 1-derived peptide (Ac(2-26)) significantly stimulates nonphlogistic phagocytosis of apoptotic polymorphonuclear leukocytes (PMNs) by human monocyte-derived macrophages (Mphi). Peptide Ac(2-26)-stimulated phagocytosis is accompanied by rearrangement of the Mphi actin cytoskeleton. To investigate the potential role of endogenous annexin on clearance of apoptotic cells, Mphi were cultured for 5 days in the presence of dexamethasone. Supernatants collected from dexamethasone-treated Mphi significantly enhanced the ability of naive Mphi to engulf apoptotic PMNs. This effect was blocked by an annexin blocking Ab, by immunodepletion of the supernatants, and by the formyl peptide receptor/lipoxin receptor antagonist Boc1. In addition, we show that bone marrow-derived Mphi from annexin 1-null mice present a 40% decreased phagocytosis of apoptotic PMNs compared with cells taken from littermate controls. In conclusion, these results emphasize the pivotal role of annexin 1 as mediator for clearance of apoptotic cells and expand its potential therapeutic role in controlling inflammatory diseases.
authors.affiliation: Department of Medicine and Therapeutics, The Conway Institute of Biomolecular and Biomedical Research, The Dublin Molecular Medicine Centre, University College Dublin, Dublin, Ireland. paola.maderna@ucd.ie
authors.forename: Paola
authors.initials: P
authors.lastname: Maderna
authors.forename: Simon
authors.initials: S
authors.lastname: Yona
authors.forename: Mauro
authors.initials: M
authors.lastname: Perretti
authors.forename: Catherine
authors.initials: C
authors.lastname: Godson
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D017305:Annexin A1 / Q000172:deficiency / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D017209:Apoptosis; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D016209:Interleukin-8 / Q000096:biosynthesis; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009504:Neutrophils / Q000166:cytology* / Q000276:immunology*; D010455:Peptides; D010587:Phagocytosis / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000096:biosynthesis
chemical_list: D000199:Actins; D017305:Annexin A1; D016209:Interleukin-8; D010455:Peptides; D016212:Transforming Growth Factor beta; C096153:annexin A1 peptide (2-26); D003907:Dexamethasone; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases