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?-1 Antitrypsin regulates human neutrophil chemotaxis induced by soluble immune complexes and IL-8.

ABSTRACT: Hereditary deficiency of the protein ?-1 antitrypsin (AAT) causes a chronic lung disease in humans that is characterized by excessive mobilization of neutrophils into the lung. However, the reason for the increased neutrophil burden has not been fully elucidated. In this study we have demonstrated using human neutrophils that serum AAT coordinates both CXCR1- and soluble immune complex (sIC) receptor-mediated chemotaxis by divergent pathways. We demonstrated that glycosylated AAT can bind to IL-8 (a ligand for CXCR1) and that AAT-IL-8 complex formation prevented IL-8 interaction with CXCR1. Second, AAT modulated neutrophil chemotaxis in response to sIC by controlling membrane expression of the glycosylphosphatidylinositol-anchored (GPI-anchored) Fc receptor Fc?RIIIb. This process was mediated through inhibition of ADAM-17 enzymatic activity. Neutrophils isolated from clinically stable AAT-deficient patients were characterized by low membrane expression of Fc?RIIIb and increased chemotaxis in response to IL-8 and sIC. Treatment of AAT-deficient individuals with AAT augmentation therapy resulted in increased AAT binding to IL-8, increased AAT binding to the neutrophil membrane, decreased Fc?RIIIb release from the neutrophil membrane, and normalization of chemotaxis. These results provide new insight into the mechanism underlying the effect of AAT augmentation therapy in the pulmonary disease associated with AAT deficiency.

SUBMITTER: Bergin DA

PROVIDER: S-EPMC2993580 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature

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α-1 Antitrypsin regulates human neutrophil chemotaxis induced by soluble immune complexes and IL-8.

Bergin David A DA Reeves Emer P EP Meleady Paula P Henry Michael M McElvaney Oliver J OJ Carroll Tomás P TP Condron Claire C Chotirmall Sanjay H SH Clynes Martin M O'Neill Shane J SJ McElvaney Noel G NG

The Journal of clinical investigation 20101108 12

Hereditary deficiency of the protein α-1 antitrypsin (AAT) causes a chronic lung disease in humans that is characterized by excessive mobilization of neutrophils into the lung. However, the reason for the increased neutrophil burden has not been fully elucidated. In this study we have demonstrated using human neutrophils that serum AAT coordinates both CXCR1- and soluble immune complex (sIC) receptor-mediated chemotaxis by divergent pathways. We demonstrated that glycosylated AAT can bind to IL- ...[more]

PMID: 21060150

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Project description:Inactivation of the plasma serine-proteinase inhibitor alpha 1-antitrypsin (alpha 1-AT) by neutrophil metalloproteinases has been reported [Vissers, George, Bathurst, Brennan & Winterbourn (1987) Fed. Proc. Fed. Am. Soc. Exp. Biol. 46, 1390a; (1988) J. Clin. Invest. 82, 706-711; Desrochers & Weiss (1988) J. Clin. Invest. 81, 1646-1650]. To identify the enzyme responsible, supernatant from neutrophils stimulated with phorbol 12-myristate 13-acetate was subjected to preparative SDS/PAGE, both with and without activation of latent metalloproteinases with HgCl2. The lanes were subsequently sliced into pieces, the slices incubated with equimolar amounts of type I collagen and alpha 1-AT in the presence of HgCl2, and the reaction products separated by SDS/PAGE. With the latent supernatant, the characteristic collagen-cleavage products and cleaved alpha 1-AT were present in the same slices, corresponding to an Mr of 80,000-85,000. On treatment with HgCl2 both degradative activities underwent the same molecular-mass shift to a position corresponding to Mr 60,000-65,000. Western blots of neutrophil supernatants, using a polyclonal antibody to purified collagenase, showed Mr values of 83,000 for the latent enzyme and 63,000 for the HgCl2-activated enzyme. Neutrophil collagenase was purified to homogeneity and shown also to exist in a second latent form with Mr 70,000. When activated to the Mr-63,000 form by HgCl2 and incubated with equimolar amounts of collagen and alpha 1-AT, collagenase cleaved alpha 1-AT at almost twice the rate at which collagen was cleaved. alpha 1-AT cleavage was inhibited by 1,10-phenanthroline and by high concentrations of collagen. That the purified collagenase did not contain a contaminant proteinase such as stromelysin was indicated by inability of the preparation to cleave casein. Taken together these results lead us to conclude that neutrophil collagenase is capable of degrading alpha 1-AT. Neutrophil gelatinase also cleaved alpha 1-AT, but cleavage was slow when compared with its activity against gelatin.

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?-1 Antitrypsin regulates human neutrophil chemotaxis induced by soluble immune complexes and IL-8.

Publications

α-1 Antitrypsin regulates human neutrophil chemotaxis induced by soluble immune complexes and IL-8.

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