title: Hypochlorous acid generated by neutrophils inactivates ADAMTS13: an oxidative mechanism for regulating ADAMTS13 proteolytic activity during inflammation.
abstract: ADAMTS13 is a plasma metalloproteinase that cleaves large multimeric forms of von Willebrand factor (VWF) to smaller, less adhesive forms. ADAMTS13 activity is reduced in systemic inflammatory syndromes, but the cause is unknown. Here, we examined whether neutrophil-derived oxidants can regulate ADAMTS13 activity. We exposed ADAMTS13 to hypochlorous acid (HOCl), produced by a myeloperoxidase-H2O2-Cl(-) system, and determined its residual proteolytic activity using both a VWF A2 peptide substrate and multimeric plasma VWF. Treatment with 25 nm myeloperoxidase plus 50 μm H2O2 reduced ADAMTS13 activity by >85%. Using mass spectrometry, we demonstrated that Met(249), Met(331), and Met(496) in important functional domains of ADAMTS13 were oxidized to methionine sulfoxide in an HOCl concentration-dependent manner. The loss of enzyme activity correlated with the extent of oxidation of these residues. These Met residues were also oxidized in ADAMTS13 exposed to activated human neutrophils, accompanied by reduced enzyme activity. ADAMTS13 treated with either neutrophil elastase or plasmin was inhibited to a lesser extent, especially in the presence of plasma. These observations suggest that oxidation could be an important mechanism for ADAMTS13 inactivation during inflammation and contribute to the prothrombotic tendency associated with inflammation.
authors.affiliation: From the Research Institute, Puget Sound Blood Center, Seattle, Washington 98104 and.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: From the Research Institute, Puget Sound Blood Center, Seattle, Washington 98104 and.
authors.forename: Junmei
authors.initials: J
authors.lastname: Chen
authors.affiliation: From the Research Institute, Puget Sound Blood Center, Seattle, Washington 98104 and.
authors.forename: Minhua
authors.initials: M
authors.lastname: Ling
authors.affiliation: From the Research Institute, Puget Sound Blood Center, Seattle, Washington 98104 and the Departments of Biochemistry and Medicine, University of Washington, Seattle, Washington 98195.
authors.forename: José A
authors.initials: JA
authors.lastname: López
authors.affiliation: From the Research Institute, Puget Sound Blood Center, Seattle, Washington 98104 and the Departments of Biochemistry and.
authors.forename: Dominic W
authors.initials: DW
authors.lastname: Chung
authors.affiliation: From the Research Institute, Puget Sound Blood Center, Seattle, Washington 98104 and Medicine, University of Washington, Seattle, Washington 98195 xiaoyunf@psbc.org.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Fu
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000071120:ADAMTS13 Protein; D002853:Chromatography, Liquid; D005341:Fibrinolysin / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D006997:Hypochlorous Acid / Q000737:chemistry*; D007249:Inflammation / Q000378:metabolism*; D019272:Leukocyte Elastase / Q000737:chemistry; D013058:Mass Spectrometry; D008715:Methionine / Q000737:chemistry; D009504:Neutrophils / Q000201:enzymology / Q000378:metabolism*; D016877:Oxidants / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D009195:Peroxidase / Q000378:metabolism; D017434:Protein Structure, Tertiary; D013927:Thrombosis / Q000378:metabolism; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D016877:Oxidants; D014841:von Willebrand Factor; D006997:Hypochlorous Acid; D008715:Methionine; D006861:Hydrogen Peroxide; D009195:Peroxidase; D019272:Leukocyte Elastase; D005341:Fibrinolysin; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human; D010100:Oxygen
keywords: ADAMTS13; HOCl; Inflammation; Methionine Oxidation; Myeloperoxidase; Neutrophil; Thrombosis