Oxidative cross-linking of calprotectin occurs in vivo, altering its structure and susceptibility to proteolysis
Calprotectin, the major neutrophil protein, is a critical alarmin that modulates inflammation and plays a role in host immunity by strongly binding trace metals essential for bacterial growth. It has two cysteine residues favourably positioned to act as a redox switch. Whether their oxidation occurs...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2019-06-01
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| Series: | Redox Biology |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2213231719302794 |
| _version_ | 1818325142159228928 |
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| author | Teagan S. Hoskin Jennifer M. Crowther Jeanette Cheung Michael J. Epton Peter D. Sly Peter A. Elder Renwick C.J. Dobson Anthony J. Kettle Nina Dickerhof |
| author_facet | Teagan S. Hoskin Jennifer M. Crowther Jeanette Cheung Michael J. Epton Peter D. Sly Peter A. Elder Renwick C.J. Dobson Anthony J. Kettle Nina Dickerhof |
| author_sort | Teagan S. Hoskin |
| collection | DOAJ |
| description | Calprotectin, the major neutrophil protein, is a critical alarmin that modulates inflammation and plays a role in host immunity by strongly binding trace metals essential for bacterial growth. It has two cysteine residues favourably positioned to act as a redox switch. Whether their oxidation occurs in vivo and affects the function of calprotectin has received little attention. Here we show that in saliva from healthy adults, and in lavage fluid from the lungs of patients with respiratory diseases, a substantial proportion of calprotectin was cross-linked via disulfide bonds between the cysteine residues on its S100A8 and S100A9 subunits. Stimulated human neutrophils released calprotectin and subsequently cross-linked it by myeloperoxidase-dependent production of hypochlorous acid. The myeloperoxidase-derived oxidants hypochlorous acid, taurine chloramine, hypobromous acid, and hypothiocyanous acid, all at 10 μM, cross-linked calprotectin (5 μM) via reversible disulfide bonds. Hypochlorous acid generated A9-A9 and A8-A9 cross links. Hydrogen peroxide (10 μM) did not cross-link the protein. Purified neutrophil calprotectin existed as a non-covalent heterodimer of A8/A9 which was converted to a heterotetramer - (A8/A9)2 - with excess calcium ions. Low level oxidation of calprotectin with hypochlorous acid produced substantial proportions of high order oligomers, whether oxidation occurred before or after addition of calcium ions. At high levels of oxidation the heterodimer could not form tetramers with calcium ions, but prior addition of calcium ions afforded some protection for the heterotetramer. Oxidation and formation of the A8-A9 disulfide cross link enhanced calprotectin's susceptibility to proteolysis by neutrophil proteases. We propose that reversible disulfide cross-linking of calprotectin occurs during inflammation and affects its structure and function. Its increased susceptibility to proteolysis will ultimately result in a loss of function. Keywords: S100A8, S100A9, Neutrophil, Myeloperoxidase, Hypochlorous acid, Hypothiocyanous acid |
| first_indexed | 2024-12-13T11:39:46Z |
| format | Article |
| id | doaj.art-f09c5a4e76404cb9bf348c333646e5cb |
| institution | Directory Open Access Journal |
| issn | 2213-2317 |
| language | English |
| last_indexed | 2024-12-13T11:39:46Z |
| publishDate | 2019-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Redox Biology |
| spelling | doaj.art-f09c5a4e76404cb9bf348c333646e5cb2022-12-21T23:47:41ZengElsevierRedox Biology2213-23172019-06-0124Oxidative cross-linking of calprotectin occurs in vivo, altering its structure and susceptibility to proteolysisTeagan S. Hoskin0Jennifer M. Crowther1Jeanette Cheung2Michael J. Epton3Peter D. Sly4Peter A. Elder5Renwick C.J. Dobson6Anthony J. Kettle7Nina Dickerhof8Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New Zealand; Corresponding author. Centre for Free Radical Research, University of Otago Christchurch, P.O. Box 4345, Christchurch, 8140, New Zealand.Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, New ZealandCanterbury Respiratory Research Group, Respiratory Services, Christchurch Hospital, Canterbury District Health Board, New ZealandCanterbury Respiratory Research Group, Respiratory Services, Christchurch Hospital, Canterbury District Health Board, New ZealandChild Health Research Centre, University of Queensland, Brisbane, AustraliaEndocrinology and Steroid Laboratory, Canterbury Health Laboratories, New ZealandBiomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand; Bio21 Molecular Science and Biotechnology Institute, Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, AustraliaCentre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New ZealandCentre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New ZealandCalprotectin, the major neutrophil protein, is a critical alarmin that modulates inflammation and plays a role in host immunity by strongly binding trace metals essential for bacterial growth. It has two cysteine residues favourably positioned to act as a redox switch. Whether their oxidation occurs in vivo and affects the function of calprotectin has received little attention. Here we show that in saliva from healthy adults, and in lavage fluid from the lungs of patients with respiratory diseases, a substantial proportion of calprotectin was cross-linked via disulfide bonds between the cysteine residues on its S100A8 and S100A9 subunits. Stimulated human neutrophils released calprotectin and subsequently cross-linked it by myeloperoxidase-dependent production of hypochlorous acid. The myeloperoxidase-derived oxidants hypochlorous acid, taurine chloramine, hypobromous acid, and hypothiocyanous acid, all at 10 μM, cross-linked calprotectin (5 μM) via reversible disulfide bonds. Hypochlorous acid generated A9-A9 and A8-A9 cross links. Hydrogen peroxide (10 μM) did not cross-link the protein. Purified neutrophil calprotectin existed as a non-covalent heterodimer of A8/A9 which was converted to a heterotetramer - (A8/A9)2 - with excess calcium ions. Low level oxidation of calprotectin with hypochlorous acid produced substantial proportions of high order oligomers, whether oxidation occurred before or after addition of calcium ions. At high levels of oxidation the heterodimer could not form tetramers with calcium ions, but prior addition of calcium ions afforded some protection for the heterotetramer. Oxidation and formation of the A8-A9 disulfide cross link enhanced calprotectin's susceptibility to proteolysis by neutrophil proteases. We propose that reversible disulfide cross-linking of calprotectin occurs during inflammation and affects its structure and function. Its increased susceptibility to proteolysis will ultimately result in a loss of function. Keywords: S100A8, S100A9, Neutrophil, Myeloperoxidase, Hypochlorous acid, Hypothiocyanous acidhttp://www.sciencedirect.com/science/article/pii/S2213231719302794 |
| spellingShingle | Teagan S. Hoskin Jennifer M. Crowther Jeanette Cheung Michael J. Epton Peter D. Sly Peter A. Elder Renwick C.J. Dobson Anthony J. Kettle Nina Dickerhof Oxidative cross-linking of calprotectin occurs in vivo, altering its structure and susceptibility to proteolysis Redox Biology |
| title | Oxidative cross-linking of calprotectin occurs in vivo, altering its structure and susceptibility to proteolysis |
| title_full | Oxidative cross-linking of calprotectin occurs in vivo, altering its structure and susceptibility to proteolysis |
| title_fullStr | Oxidative cross-linking of calprotectin occurs in vivo, altering its structure and susceptibility to proteolysis |
| title_full_unstemmed | Oxidative cross-linking of calprotectin occurs in vivo, altering its structure and susceptibility to proteolysis |
| title_short | Oxidative cross-linking of calprotectin occurs in vivo, altering its structure and susceptibility to proteolysis |
| title_sort | oxidative cross linking of calprotectin occurs in vivo altering its structure and susceptibility to proteolysis |
| url | http://www.sciencedirect.com/science/article/pii/S2213231719302794 |
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