Proteinase 3, the Wegener autoantigen, is externalized during neutrophil apoptosis: evidence for a functional association with phospholipid scramblase 1 and interference with macrophage phagocytosis.
Proteinase 3 (PR3), a serine proteinase contained in neutrophil azurophilic granules, is considered a risk factor for vasculitides and rheumatoid arthritis when expressed on the outer leaflet of neutrophil plasma membrane and is the preferred target of antineutrophil cytoplasm autoantibodies (ANCA) in Wegener granulomatosis. ANCA binding to PR3 expressed at the surface of neutrophils activates them. Evidence is provided that neutrophil apoptosis induced significantly more membrane PR3 expression without degranulation (but no enhanced membrane CD35, CD66b, CD63, myeloperoxidase, or elastase expression). This observation was confirmed on cytoplasts, a model of granule-free neutrophils. We hypothesized that PR3 could interact with proteins involved in membrane flip-flop (eg, phospholipid scramblase 1 [PLSCR1]). PR3-PLSCR1 interaction in neutrophils was demonstrated by confocal microscopy and coimmunoprecipitation. In the RBL-2H3 rat mast-cell line stably transfected with PR3 or its inactive mutant (PR3S203A), PR3 externalization depended on PLSCR1, as shown by less PR3 externalization in the presence of rPLSCR1 siRNA, but independently of its serine-proteinase activity. Finally, apoptosis-externalized PR3 decreased the human macrophage-phagocytosis rate of apoptotic PR3 transfectants. Therefore, in addition to ANCA binding in vasculitis, the proinflammatory role of membrane PR3 expression may involve interference with macrophage clearance of apoptotic neutrophils.
Kantari
Chahrazade
C
Institut National de la Santé et de la Recherche Médicale, U845, Paris, France
Pederzoli-Ribeil
Magali
M
Amir-Moazami
Omid
O
Gausson-Dorey
Valérie
V
Moura
Ivan Cruz
IC
Lecomte
Marie-Christine
MC
Benhamou
Marc
M
Witko-Sarsat
Véronique
V
D000818:Animals; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000276:immunology / Q000378:metabolism; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000201:enzymology / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology / Q000235:genetics / Q000276:immunology; D015971:Gene Expression Regulation, Enzymologic / Q000276:immunology; D014890:Granulomatosis with Polyangiitis / Q000201:enzymology / Q000235:genetics / Q000276:immunology; D006801:Humans; D008264:Macrophages / Q000201:enzymology* / Q000276:immunology; D008407:Mast Cells / Q000201:enzymology / Q000276:immunology; D009154:Mutation / Q000276:immunology; D053146:Myeloblastin / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018375:Neutrophil Activation / Q000235:genetics / Q000276:immunology; D009504:Neutrophils / Q000201:enzymology* / Q000276:immunology / Q000378:metabolism; D010196:Pancreatic Elastase / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D009195:Peroxidase / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D010587:Phagocytosis / Q000235:genetics / Q000276:immunology; D049294:Phospholipid Transfer Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D021381:Protein Transport / Q000235:genetics / Q000276:immunology; D034741:RNA, Small Interfering / Q000235:genetics / Q000276:immunology; D051381:Rats; D012307:Risk Factors; D022142:Secretory Vesicles / Q000201:enzymology / Q000235:genetics / Q000276:immunology; D014657:Vasculitis / Q000201:enzymology / Q000235:genetics / Q000276:immunology
D019268:Antibodies, Antineutrophil Cytoplasmic; D015703:Antigens, CD; C493422:PLSCR1 protein, human; D049294:Phospholipid Transfer Proteins; D034741:RNA, Small Interfering; D009195:Peroxidase; D010196:Pancreatic Elastase; D053146:Myeloblastin